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Report to the Chairman, Subcommittee on Aviation, Committee on 
Transportation and Infrastructure, House of Representatives:

November 2004:

AIR TRAFFIC CONTROL:

FAA Needs to Ensure Better Coordination When Approving Air Traffic 
Control Systems:

[Hyperlink, http://www.gao.gov/cgi-bin/getrpt?GAO-05-11]:

GAO Highlights:

Highlights of GAO-05-11, a report to the Chairman, House Aviation 
Subcommittee, Committee on Transportation and Infrastructure: 

Why GAO Did This Study:

The Federal Aviation Administration’s (FAA) process for ensuring that 
air traffic control (ATC) systems will operate safely in the national 
airspace system is an integral part of the agency’s multibillion-dollar 
ATC modernization and safety effort. GAO was asked to review (1) FAA’s 
process for approving ATC systems for safe use in the national airspace 
system; (2) challenges FAA has faced approving ATC systems and how 
these challenges affected the cost, schedule, and performance estimates 
of the systems; and (3) actions FAA has taken to improve its process 
for approving ATC systems.

What GAO Found:

FAA has separate processes for approving ground systems and certifying 
aircraft equipment for safe use in the national airspace system. FAA’s 
process for approving ground systems, such as radar systems, is done in 
accordance with policies and procedures in FAA’s Acquisition Management 
System. Approving ground systems, which are usually developed, owned, 
and operated by FAA, typically involves FAA’s Air Traffic Organization 
determining whether a vendor is in compliance with contract 
requirements, followed by a rigorous test-and-evaluation process to 
ensure that the new system will operate safely in the national airspace 
system. The process for certifying aircraft equipment, which is usually 
developed by private companies, is done in accordance with Federal 
Aviation Regulations, with FAA serving as the regulator. If a system 
has both ground components and aircraft equipment components, then the 
system must go through both processes before it is approved for safe 
use in the national airspace system.

FAA has faced challenges approving systems for safe use in the national 
airspace system that contributed to cost growth, delays, and 
performance shortfalls in deploying these systems. We identified three 
specific challenges through the review of 5 ATC systems and our past 
work. These challenges are the need to (1) involve appropriate 
stakeholders, such as users and technical experts, throughout the 
approval process; (2) ensure that the FAA offices that have 
responsibility for approving ground systems and certifying aircraft 
equipment effectively coordinate their efforts for integrated systems; 
and (3) accurately estimate the amount of time needed to meet complex 
technical requirements at the beginning of the design and development 
phase.

FAA has taken some actions to address two of the three challenges we 
identified. However, FAA has not taken action to fully involve all 
stakeholders, such as air traffic controllers and technical experts, 
throughout the approval process. FAA officials believe that the 
agency’s new Safety Management System will help ensure that the ground 
system approval and aircraft certification processes are better 
coordinated. FAA stated that coordination would improve because, as 
part of the new Safety Management System, the agency plans to realign 
its organizational structure to create a formal link between the Air 
Traffic Organization and the Office of Regulation and Certification. 
FAA expects full implementation of this system to take 3 to 5 years. 
We are reserving judgment on whether this change will fully address 
the challenge because of the early state of this effort and FAA’s long-
standing problems with internal coordination when approving ATC 
systems. As such, we believe that FAA should, in the interim, develop 
specific plans that describe how both internal and external 
coordination will occur on a system-specific basis.

What GAO Recommends:

GAO is recommending that FAA develop ATC system-specific plans early in 
the approval process that specify how and when the approving and 
certifying offices within FAA and other stakeholders, including 
controllers, maintenance technicians, technical experts, and industry 
representatives, will meet to ensure coordination. FAA generally agreed 
with the findings and recommendation in this report

www.gao.gov/cgi-bin/getrpt?GAO-05-11.

To view the full product, including the scope and methodology, click on 
the link above. For more information, contact Katherine Siggerud at 
(202) 512-2834 or siggerudk@gao.gov.

[End of section]

Contents:

Letter:

Results in Brief:

Background:

FAA Has Separate Processes for Approving Ground Systems and Certifying 
Aircraft Equipment:

FAA Faced Challenges in Approving Several ATC Systems:

FAA Has Taken Action to Improve Its Process for Approving ATC Systems:

Conclusions:

Recommendation for Executive Action:

Agency Comments:

Appendixes:

Appendix I: Objectives, Scope, and Methodology:

Appendix II: Airport Surface Detection Equipment - Model X Case 
Illustration:

Background:

Status:

FAA Faced Fewer Challenges in Approving ASDE-X:

Appendix III: Controller-Pilot Data Link Communications Case 
Illustration:

Background:

Status:

Challenges in Approving CPDLC:

Appendix IV: Local Area Augmentation System Case Illustration:

Background:

Status:

FAA Faced Challenges in Approving LAAS:

Certification of LAAS Aircraft Equipment Has Been Affected by Delays in 
Ground System Approval:

FAA's Aircraft Certification Office Needs to Coordinate Better with 
Acquisition Offices:

Appendix V: Standard Terminal Automation Replacement System Case 
Illustration:

Background:

Status:

FAA Faced Challenges in Approving STARS:

Appendix VI: Wide Area Augmentation System Case Illustration:

Background:

Status:

FAA Faced Challenges in Approving WAAS:

FAA Did Not Experience Major Challenges in Certifying the Aircraft 
Equipment of WAAS:

Appendix VII: GAO Contacts and Staff Acknowledgments:

GAO Contacts:

Staff Acknowledgments:

Tables:

Table 1: FAA Systems Used as Case Illustrations:

Table 2: Cost and Schedule Estimate Changes to ASDE-X:

Table 3: ASDE-X Ground System Approval Timeline:

Table 4: Cost and Schedule Estimate Changes to CPDLC:

Table 5: CPDLC Ground System Approval Timeline (Build 1):

Table 6: CPDLC Ground System Approval Timeline (Build 1A):

Table 7: CPDLC Aircraft Equipment Certification Timeline:

Table 8: Cost and Schedule Estimate Changes to LAAS:

Table 9: LAAS Ground System Approval Timeline:

Table 10: LAAS Aircraft Equipment Certification Timeline:

Table 11: Cost and Schedule Estimate Changes to STARS:

Table 12: STARS Ground System Approval Timeline:

Table 13: Cost and Schedule Baseline Changes to WAAS:

Table 14: WAAS Ground System Approval Timeline:

Table 15: WAAS Aircraft Equipment Certification Timeline:

Figures:

Figure 1: Current FAA Offices with Responsibility for Approving Air 
Traffic Control Systems:

Figure 2: Airport Surface Detection Equipment - Model X:

Figure 3: Controller-Pilot Data Link Communications:

Figure 4: LAAS Infrastructure:

Figure 5: Standard Terminal Automation Replacement System:

Figure 6: WAAS Architecture:

Abbreviations: 

ASDE-X: Airport Surface Detection Equipment - Model X:

ATC: air traffic control:

CPDLC: Controller-Pilot Data Link Communications:

DOD: Department of Defense:

FAA: Federal Aviation Administration:

GPS: Global Positioning System:

LAAS: Local Area Augmentation System:

STARS: Standard Terminal Automation Replacement System:

WAAS: Wide Area Augmentation System:

Letter November 17, 2004:

The Honorable John L. Mica: 
Chairman, Subcommittee on Aviation: 
Committee on Transportation and Infrastructure: 
House of Representatives:

Dear Mr. Chairman:

The Federal Aviation Administration's (FAA) process for ensuring that 
air traffic control systems will operate safely in the national 
airspace system is an integral part of FAA's multibillion-dollar air 
traffic control modernization and safety effort. New air traffic 
control systems cannot be used in the national airspace system until 
FAA has determined that the systems will operate safely. Over the 
years, FAA has approved about 45,000 pieces of air traffic control 
equipment for safe use in the national airspace system. Some in the 
aviation industry and government contend that FAA's approval process 
for air traffic control systems is too lengthy and, therefore, 
contributes to cost growth, schedule delays, and performance problems 
that have plagued many of the systems that FAA has been trying to 
develop for years. In addition, some in the aviation industry have 
raised concerns about whether FAA's approval process has kept pace with 
changes in technology. For example, more of today's new air traffic 
control systems are integrated--that is, involving both ground 
systems[Footnote 1] and equipment used exclusively in aircraft 
(aircraft equipment) that must work together--than in the past.

In response to your request, we examined:

* FAA's process for approving air traffic control systems for safe use 
in the national airspace system;

* challenges FAA faces in approving air traffic control systems and how 
these challenges have affected the cost, schedule, and performance of 
the systems; and:

* actions FAA has taken to improve its process for approving air 
traffic control systems.

In this report, we use the word "approval" to describe the process of 
ensuring the safety of an air traffic control system when it has both a 
ground system and aircraft equipment. We also use the word "approval" 
to describe the process of ensuring the safety of ground systems 
exclusively. We use the word "certification" to describe the process of 
ensuring the safety of aircraft equipment for safe use in the national 
airspace system.

To identify FAA's process for approving air traffic control systems for 
safe use in the national airspace system, we reviewed FAA documents 
that describe the agency's process for approving such systems and 
equipment and RTCA's 1999 and 2001 reports that also address this 
process.[Footnote 2] To determine the challenges FAA has faced in 
approving air traffic control systems and how these challenges affected 
the cost, schedule, and performance of the systems, we (1) conducted 
case illustrations on 5 of FAA's 25 air traffic control systems 
currently receiving funding that were approved or in the process of 
being approved for safe use in the national airspace system and (2) 
reviewed reports prepared by GAO and the Department of Transportation's 
Inspector General. The 5 air traffic control systems are:

* Airport Surface Detection Equipment - Model X (ASDE-X),

* Controller-Pilot Data Link Communications (CPDLC),

* Local Area Augmentation System (LAAS),

* Standard Terminal Automation Replacement System (STARS), and:

* Wide Area Augmentation System (WAAS).

We selected these 5 systems because collectively they accounted for 
about 46 percent of FAA's air traffic control modernization costs in 
fiscal year 2002 and 3 of the 5 systems are integrated--that is, they 
require the approval of the ground systems as well as certification of 
aircraft equipment before they can be used in the national airspace 
system. In addition, we interviewed, among others, officials from FAA 
program offices; RTCA; aviation industry groups; manufacturers of 
aircraft equipment; ground system developers, including Honeywell, 
Raytheon, and Sensis Corporation; industry experts; Wide Area 
Augmentation System Integrity Performance Panel[Footnote 3] and Local 
Area Augmentation System Integrity Panel members;[Footnote 4] and 
unions representing air traffic controllers and maintenance 
technicians. We also reviewed reports on air traffic control systems 
prepared by GAO, the Department of Transportation's Inspector General, 
RTCA, and the Commission on the Future of the U.S. Aerospace Industry 
(Aerospace Commission). To identify what actions FAA has taken to 
improve its processes for approving air traffic control systems, we 
interviewed representatives from FAA, RTCA, the Aerospace Commission, 
and aviation industry groups. See appendix I for additional information 
on our objectives, scope, and methodology. We conducted our review from 
October 2003 through September 2004 in accordance with generally 
accepted government auditing standards.

Results in Brief:

FAA has separate processes for approving ground systems and certifying 
aircraft equipment for safe use in the national airspace system. FAA's 
process for approving ground systems, such as radar systems, is done in 
accordance with policies and procedures in FAA's Acquisition Management 
System. The process to approve ground systems, which are usually 
developed, owned, and operated by FAA, involves FAA's Air Traffic 
Organization determining whether a vendor is in compliance with 
contract requirements and/or FAA operational requirements, followed by 
a rigorous test-and-evaluation process to ensure that the new system 
will operate safely in the national airspace system. In contrast, 
federal aviation law requires that aircraft equipment, which is usually 
developed by private companies, be certified in accordance with Federal 
Aviation Regulations, with FAA serving as the regulator. Unlike the 
approval of ground systems, which FAA accomplishes with the help of a 
contractor, FAA is not typically involved in the development of the 
equipment. An applicant, such as a manufacturer of aircraft equipment, 
generally brings fully developed aircraft equipment to FAA for 
certification. If an air traffic control system has both a ground 
system and aircraft equipment, as was the case for 3 of the 5 systems 
we reviewed, then the system must go through both processes before it 
is approved for safe use in the national airspace system.

FAA has faced challenges in approving air traffic control systems for 
safe use in the national airspace system. This report focuses on three 
specific challenges we identified through our past work and our case 
illustrations of 5 air traffic control systems. Most of these 
challenges have made it more difficult for FAA to meet the systems' 
cost, schedule, or performance estimates. These challenges are as 
follows:

* Involving appropriate stakeholders, such as users and technical 
experts, throughout the ground system approval process. For example, 
during the design and development phase of the Standard Terminal 
Automation Replacement System, which is designed to replace air traffic 
controller workstations with new color displays, FAA did not involve 
users such as air traffic controllers and maintenance technicians in 
human factor evaluations, which examine how humans interact with 
machines, because the aggressive development schedule limited the 
amount of time available to involve them. Consequently, FAA and the 
contractor later had to restructure the contract to address the 
controllers' and technicians' concerns, such as the inconsistency of 
visual warning alarms and color codes, which contributed to the system 
being delayed by 3 years and a cost increase of $500 million.

* Ensuring that the FAA offices that have responsibility for approving 
ground systems and certifying aircraft equipment effectively coordinate 
their efforts for integrated systems. For example, although the Wide 
Area Augmentation System was being developed by an integrated product 
team that included representatives from various FAA offices, the team 
did not function effectively in resolving issues related to meeting an 
important functional requirement to alert the pilot in a timely manner 
when the system should not be used because of a possible error. 
According to FAA officials, the reason coordination was not effective 
was because the two offices had competing priorities that were not 
associated with development of the Wide Area Augmentation System. This 
ineffective coordination, combined with other factors, contributed to a 
6-year delay in commissioning the Wide Area Augmentation System and a 
$1.5 billion increase in its development costs.

* Accurately estimating the amount of time needed to meet complex 
requirements at the beginning of the design and development phase. For 
example, FAA accelerated the schedule for the Standard Terminal 
Automation Replacement System in 1995. This acceleration in schedule 
left only limited time for human factor evaluations and, according to 
FAA officials, added $500 million to the Standard Terminal Automation 
Replacement System's cost and 3 years to the schedule because the 
agency had to revise its strategy for acquiring and approving it.

FAA has taken actions to address two of the three challenges we 
identified. However, FAA has not taken action to fully involve all 
stakeholders, such as air traffic controllers, maintenance technicians, 
technical experts, and industry representatives, throughout the 
approval process. To ensure that the two offices effectively coordinate 
their ground system approval and aircraft equipment certification 
processes, FAA officials believe that the agency's new Safety 
Management System, which is designed to formalize and standardize the 
agency's safety process, will improve overall coordination among FAA 
stakeholders once the system is implemented. FAA stated that 
coordination would improve because, as part of the new Safety 
Management System, the agency plans to realign its organizational 
structure to create a formal link between the Air Traffic Organization, 
which currently approves ground systems, and the Office of Regulation 
and Certification. FAA expects full implementation of this system to 
take 3 to 5 years. We are reserving judgment on whether this change 
will fully address the challenge because of the early state of this 
effort and because FAA's problems with internal coordination when 
approving air traffic control systems are long-standing. In addition, 
because FAA has historically faced internal and external coordination 
challenges in approving air traffic control systems for safe use in the 
national airspace system, we believe that as FAA moves forward with 
implementing the agency's new Safety Management System, it should, in 
the interim, develop plans that describe:

how both internal and external coordination will occur on a system-
specific basis. In addition, plans to include external stakeholders are 
particularly important since the Safety Management System is not 
intended to address this challenge.

We are recommending that FAA develop early in the approval process air 
traffic control system-specific plans that specify how and when the 
approving and certifying offices within FAA and other stakeholders, 
including controllers, maintenance technicians, technical experts, and 
industry representatives, will meet to ensure coordination.

Background:

Several offices within FAA's Air Traffic Organization and Office of 
Regulation and Certification have responsibility for approving ground 
systems and certifying aircraft equipment, as shown in figure 1.

Figure 1: Current FAA Offices with Responsibility for Approving Air 
Traffic Control Systems:

[See PDF for image]

Note: The Office of Regulation and Certification's Air Traffic Safety 
Oversight Service oversees and collaborates with the Air Traffic 
Organization's Safety Services on the safety of air traffic control 
systems.

[End of figure]

Before the creation of the Air Traffic Organization in November 2003, 
FAA's Research and Acquisitions (acquisitions office) and Air Traffic 
Services were the primary offices responsible for approving ground 
systems for safe use in the national airspace system. The 5 systems 
that we reviewed began the approval process under that structure. 
Currently, these offices, although renamed, form the core of the Air 
Traffic Organization. The responsibilities of Air Traffic Services are 
now distributed among several offices, including System Operations 
Services and Terminal Services. The responsibilities of Research and 
Acquisitions are distributed among several offices, including Technical 
Operations Services and En Route and Oceanic Services. In addition, the 
Air Traffic Organization includes Safety Services, which is its focal 
point for safety, quality assurance, and quality control and is the 
primary interface with FAA's Office of Regulation and Certification.

FAA's Office of Regulation and Certification has responsibility for 
certifying and regulating aircraft and its equipment. The following 3 
offices within the Office of Regulation and Certification are involved 
in the certification of aircraft equipment:

* Aircraft Certification Service (aircraft certification office) is 
responsible for administering safety standards for aircraft and 
aircraft equipment that are manufactured in the United States.

* Flight Standards Service is responsible for granting operational 
approval to air carriers that plan to use equipment on their aircraft.

* Air Traffic Safety Oversight Service is responsible for monitoring 
the safety of air traffic operations through the establishment, 
approval, and acceptance of safety standards and the monitoring of 
safety performance and trends. It will also improve coordination 
between the Office of Regulation and Certification and the Air Traffic 
Organization.

In addition to the internal FAA stakeholders, the approval of air 
traffic control (ATC) systems can also involve a number of other 
external stakeholders. FAA generally makes the decision about which 
other stakeholders will be involved in approving ATC systems for safe 
use in the national airspace system. For example, stakeholders involved 
in approving ATC systems may include:

* technical experts;

* ground system developers;

* manufacturers of aircraft equipment;

* aviation industry groups;

* general aviation; and:

* users, such as controllers and maintenance technicians.

FAA also regularly requests RTCA, a private, not-for-profit 
corporation, to develop consensus-based performance standards for the 
aircraft equipment component of ATC systems. RTCA functions as a 
federal advisory committee that provides recommendations used by FAA as 
the basis for policy, program, and regulatory decisions and by the 
private sector as the basis for development, investment, and other 
business decisions.

In this report, we focus on the approval of the 5 ATC systems described 
in table 1 and further discussed in appendixes II through VI.

Table 1: FAA Systems Used as Case Illustrations:

System: Airport Surface Detection Equipment - Model X (ASDE-X); 
Description: ASDE-X is a traffic management system that air traffic 
controllers use to track aircraft and vehicle movement at an airport. 
ASDE-X was developed to prevent runway accidents. It also provides 
aircraft identification from an airport's surface. ASDE-X uses a 
combination of surface movement radar and sensors to display aircraft 
position on an ATC tower display. The integration of these sensors 
provides accurate, up-to-date, and reliable data to improve airport 
safety in all weather conditions.

System: Controller-Pilot Data Link Communications (CPDLC); 
Description: CPDLC allows pilots and controllers to transmit digital 
messages directly between an FAA ground automation system and suitably 
equipped aircraft. CPDLC is a new way for controllers and pilots to 
communicate that is analogous to e-mail. This system is meant to 
alleviate voice congestion problems and increase controller 
efficiency.

System: Local Area Augmentation System (LAAS); 
Description: LAAS is a precision approach and landing system that 
relies on the Global Positioning System (GPS) to broadcast highly 
accurate information to aircraft on the final phases of a flight. LAAS 
is being developed specifically to augment GPS satellites to support 
precision approaches and landing capability to aircraft operating 
within a 20-to 30-mile radius of the airport. LAAS approaches will be 
designed to avoid obstacles, restricted airspace, noise-sensitive 
areas, or congested airspace.

System: Standard Terminal Automation Replacement System (STARS); 
Description: STARS replaces controller workstations with new color 
displays, processors, and computer software at the FAA and the 
Department of Defense terminal ATC facilities. FAA's goal for STARS is 
to provide an open, expandable terminal automation platform that can 
accommodate future air traffic growth and allow for the introduction of 
new hardware-and software-based tools to promote safety, maximize 
operational efficiency, and improve controllers' productivity.

System: Wide Area Augmentation System (WAAS); 
Description: WAAS is a GPS-based navigation and landing system that is 
meant to improve safety by providing precision guidance to aircraft for 
all phases of flight at thousands of airports and landing strips where 
there is no ground-based landing capability. WAAS consists of 25 ground 
reference stations, 2 leased geostationary satellites, 2 master 
stations, and 4 uplink stations. The ground reference stations are 
strategically positioned across the United States to collect GPS 
satellite data. WAAS is designed to improve the accuracy, integrity, 
and availability of information coming from GPS satellites and to 
correct signal errors caused by solar storms, timing, and satellite 
errors. Unlike conventional ground-based navigation aids, WAAS provides 
curved precision approach paths in order to avoid obstacles, restricted 
airspace, noise-sensitive areas, and congested airspace.

Source: FAA.

[End of table]

FAA Has Separate Processes for Approving Ground Systems and Certifying 
Aircraft Equipment:

FAA has separate processes for approving ground systems and certifying 
aircraft equipment for safe use in the national airspace system. FAA's 
process for approving ground systems, such as radar systems, is done in 
accordance with policies and procedures in FAA's Acquisition Management 
System.[Footnote 5] This process involves a determination by FAA's Air 
Traffic Organization regarding whether a vendor is in compliance with 
contract requirements and/or FAA operational requirements, followed by 
a rigorous test-and-evaluation process to ensure that the new system 
will operate safely in the national airspace system. In contrast, the 
process for certifying aircraft equipment, which is usually developed 
by private companies, is done in accordance with Federal Aviation 
Regulations, with FAA serving as the regulator. If an ATC system has 
both a ground system and aircraft equipment, as was the case for 3 of 
the 5 systems we reviewed, then the system must go through both 
processes before it is approved for safe use in the national airspace 
system.

Ground System Approval Process:

The approval of a ground system focuses on safety and is done in 
accordance with FAA contract documents and policies and procedures that 
are part of the agency's Acquisition Management System. Most ground 
systems that provide air traffic services and air navigation services 
are developed, owned, and operated by FAA. Prior to November 2003, 
FAA's Research and Acquisitions and Air Traffic Service offices were 
responsible for the approval of ground systems. Currently, FAA's Air 
Traffic Organization has primary responsibility for the approval of 
ground systems. FAA's ground system approval process includes the 
following six phases--concept of operations, requirements setting, 
design and development, test and evaluation, operational readiness, 
commissioning--and involves various stakeholders, which are also noted 
below.

* Concept of operations: The ground system approval process begins with 
the concept of operations phase. If the system being developed has both 
a ground system and aircraft equipment, FAA's Office of Regulation and 
Certification, Air Traffic Services Office, and Acquisitions Office 
may work together to develop the concept of operations.[Footnote 6] 
During this phase, FAA generally identifies and defines a service or 
capability to meet a particular need in the national airspace system 
and may involve other stakeholders, such as air traffic 
controllers.[Footnote 7] FAA also defines the roles and 
responsibilities of key participants, such as controllers and 
maintenance technicians, and the key elements of the required 
capability. The concept of operations phase is not a static process. As 
FAA obtains more information about the system it develops, the concept 
is revised to reflect the new information even though the next phase of 
the process may have already begun. Potential stakeholders in this 
phase include FAA's Office of Regulation and Certification, FAA's Air 
Traffic Organization, aircraft manufacturers, aviation industry 
associations, airlines, air traffic controllers, maintenance 
technicians, manufacturers of aircraft equipment, ground system 
developers, and representatives of general aviation.

* Requirements setting: During the requirements-setting phase, FAA 
establishes a minimum set of requirements, including safety objectives, 
and specifies how well the new system must perform its intended 
functions. For example, it was during this phase that FAA established 
WAAS' and LAAS' integrity requirement--which is that the system cannot 
fail to warn pilots of misleading information that could potentially 
create hazardous situations more than once in 10 million approaches. 
After analyzing the initial requirements and comparing the cost, 
benefits, schedule, and risk of various solutions, FAA sets final 
requirements and presents them to the Joint Resources Council as part 
of the investment plan.[Footnote 8] After the council has approved the 
requirements for the new system, FAA will issue a request for 
proposals, evaluate the offers received, and select a contractor to 
design a system based on the requirements set by FAA. Potential 
stakeholders in this phase include FAA's Office of Regulation and 
Certification, FAA's Air Traffic Organization, aircraft manufacturers, 
aviation industry associations, airlines, air traffic controllers, 
maintenance technicians, manufacturers of aircraft equipment, ground 
system developers, and representatives of general aviation.

* Design and development: The design and development of ground systems 
is generally completed by a contractor and monitored by FAA. During 
this phase, the contractor conducts preliminary and critical design 
reviews, which include plans for how it will conduct the testing phase. 
FAA must approve these plans before the contractor can proceed to the 
next phase. Potential stakeholders in this phase include FAA, ground 
system developers, air traffic controllers, and maintenance 
technicians.

* Test and evaluation: After FAA has approved the design and 
development of the system, it is ready to be tested and evaluated. The 
testing and evaluation of ground systems typically includes three major 
tests: development tests, operational tests, and an independent 
operational test and evaluation. Development testing is performed by 
the contractor to verify compliance with contractual requirements and 
is overseen by FAA. Operational testing is performed by FAA and is 
designed to demonstrate that a new system is operationally effective 
and suitable for use in the national airspace system. An independent 
operational test and evaluation is a full system-level evaluation 
conducted by FAA in an operational environment to confirm the 
operational readiness of a system to be part of the national airspace 
system. Potential stakeholders in this phase include FAA, ground system 
developers, air traffic controllers, and maintenance technicians.

* Operational readiness: During the operational readiness phase, FAA 
personnel are trained to operate and maintain the new system, usually 
in conjunction with its predecessor system. Following operational 
readiness approval, the system is ready to be commissioned. Potential 
stakeholders in this phase include FAA, ground system developers, air 
traffic controllers, and maintenance technicians.

* Commissioning: The commissioning phase ensures that the new ground 
system as installed meets the intended mission and operational 
requirements and is fully supported by the national airspace system 
infrastructure. Potential stakeholders in this phase include FAA, 
ground system developers, air traffic controllers, and maintenance 
technicians.

Aircraft Equipment Certification Process:

In contrast to the ground system approval process, certification of 
aircraft equipment is done in accordance with procedures outlined in 
the Federal Aviation Regulations, Title 14, Code of Federal 
Regulations, Part 21. Under Title 49, Section 44704, of the U.S. Code, 
FAA has the authority to issue type certificates, supplemental type 
certificates, and production certificates, among others, for aircraft 
and equipment that will be used in the national airspace 
system.[Footnote 9] Unlike the approval of ground systems, which FAA 
accomplishes with the help of a contractor, FAA is the regulator of 
aircraft equipment and is not typically involved in the development of 
the equipment. An applicant, such as a manufacturer of aircraft 
equipment, generally brings fully developed aircraft equipment to FAA 
for certification. The aircraft equipment certification process 
includes the following five phases--concept of operations, requirements 
setting, design and production approval, installation approval, and 
operational approval--and involves several stakeholders, which are also 
noted below:

* Concept of operations: Like the ground system approval process, the 
aircraft equipment certification process generally begins with the 
concept of operations phase, when the aircraft equipment is part of an 
ATC system. If the aircraft equipment certification process is not 
associated with the approval of a new ground system, then the 
certification process may begin with an idea for better equipment. 
During this phase, FAA, sometimes with the help of industry, identifies 
and defines a service or capability to meet a particular need in the 
national airspace system.[Footnote 10] Potential stakeholders in this 
phase include FAA's Office of Regulation and Certification, FAA's Air 
Traffic Organization, aircraft manufacturers, aviation industry 
associations, airlines, air traffic controllers, maintenance 
technicians, manufacturers of aircraft equipment, ground system 
developers, and representatives of general aviation.

* Requirements setting: Once FAA has identified the need for a new 
system with aircraft equipment, FAA determines the requirements for:

the aircraft equipment.[Footnote 11] In some cases, the requirements 
for aircraft equipment may already exist in the Federal Aviation 
Regulations. In other cases, FAA may ask RTCA to develop the 
requirements, including safety requirements, which are referred to as 
minimum operating performance standards. RTCA typically takes 1 to 5 
years to develop the standards because of the need to reach consensus 
between FAA and the industry and the increasing complexity of systems 
being developed today. According to a RTCA official, the time required 
to develop recommended standards is a function of many variables, 
including urgency of the situation and the commitment and availability 
of government and industry volunteers to collaboratively develop the 
standards. For example, in the case of WAAS, RTCA began setting 
performance standards in 1994, completed the original version of the 
standards in January 1996, and completed the most recent version of 
WAAS performance standards in November 2001. Potential stakeholders in 
this phase include FAA's Office of Regulation and Certification, FAA's 
Air Traffic Organization, aircraft manufacturers, aviation industry 
associations, airlines, air traffic controllers, maintenance 
technicians, manufacturers of aircraft equipment, ground system 
developers, and representatives of general aviation.

* Design and production approval: The requirements/performance 
standards, most often developed by RTCA, typically form the basis for a 
technical standard order, which FAA uses to grant design and production 
approval for most new aircraft equipment developed in support of 
national airspace system modernization efforts. Technical standard 
orders are FAA's requirements for materials, parts, processes, and 
appliances used on civil aircraft.[Footnote 12] Most aircraft 
manufacturers want technical standard orders because they make 
installation approval simpler and less costly and allow for operation 
in any type of aircraft. Technical standard orders are issued for items 
ranging from safety belts to navigation equipment. If the applicant 
successfully completes the design and production approval phase, FAA 
provides the applicant with a technical standard order authorization 
letter, which states that the applicant has met a specific technical 
standard order and the product is now ready for the installation 
approval phase. Potential stakeholders in this phase include FAA's 
Aircraft Certification Service, manufacturers of aircraft equipment, 
and aircraft manufacturers.

* Installation approval: After receiving a technical standard order 
authorization for new aircraft equipment, the initial applicant must 
receive installation approval from FAA before the aircraft equipment 
may be used in the national airspace system. To receive installation 
approval, the applicant submits a certification plan and test plan to 
one of FAA's aircraft certification offices for review and approval. In 
addition, the applicant conducts ground and flight tests under FAA's 
supervision to ensure that the new equipment operates properly upon 
installation. Once the tests are completed to FAA's satisfaction, FAA 
issues a supplemental type certificate, which is evidence of FAA's 
approval to modify an aircraft from its original design. Potential 
stakeholders in this phase include FAA's Aircraft Certification 
Service, manufacturers of aircraft equipment, and aircraft 
manufacturers.

* Operational approval: Finally, for the aircraft equipment to become 
certified for use in the national airspace system by air carrier 
operators, operational approval is also needed from FAA. To obtain 
operational approval, the applicant must successfully demonstrate, 
among other things, that the pilots are properly trained to use the 
aircraft equipment and that maintenance personnel are properly trained 
to maintain the equipment. Potential stakeholders in this phase include 
FAA's Flight Standards Service, airlines, and representatives of 
general aviation.

FAA Faced Challenges in Approving Several ATC Systems:

FAA faced challenges in approving systems for safe use in the national 
airspace system that contributed to cost growth, delays, and 
performance shortfalls in deploying these systems. We identified three 
specific challenges through the review of 5 ATC systems and our past 
work.[Footnote 13] These challenges are the need to:

* involve appropriate stakeholders, such as users and technical 
experts, throughout the approval process;

* ensure that the FAA offices that have responsibility for approving 
ground systems and certifying aircraft equipment effectively coordinate 
their efforts for integrated systems; and:

* accurately estimate the amount of time needed to meet complex 
technical requirements at the beginning of the design and development 
phase.

Although most of the challenges we found relate to the ground system 
approval process, RTCA and the Aerospace Commission have identified 
challenges with FAA's aircraft equipment certification process. For 
example, RTCA found that there was a need for better internal FAA 
communication and coordination, including the establishment of an 
organizational focal point to provide coordinated responses to all 
matters related to ground systems and aircraft equipment. In addition, 
the Aerospace Commission found that FAA's regulatory process needs to 
be streamlined to enable the timely development of regulations needed 
to address new technologies.

FAA Did Not Always Adequately Involve Appropriate Stakeholders, Such as 
Users and Technical Experts, Throughout Its Approval Process:

FAA failed to adequately involve appropriate stakeholders, such as air 
traffic controllers and maintenance technicians, for 3 of the 5 systems 
we reviewed. For example, FAA did not adequately involve controllers 
and maintenance technicians throughout the approval process of STARS, 
which will replace controller workstations with new color displays, 
processors, and computer software. Although controllers and technicians 
were involved in developing requirements for STARS in 1994 prior to the 
1996 contract award to Raytheon, the original approved acquisition plan 
provided for only limited human factors evaluation by controllers and 
technicians during STARS' design and development because the aggressive 
development schedule limited the amount of time available to involve 
them.[Footnote 14] Consequently, FAA and Raytheon had to restructure 
the contract to address controllers' concerns that were identified 
later, such as the inconsistency of visual warning alarms and color 
codes with the new system. According to FAA officials, not involving 
controllers and maintenance technicians in the design phase caused the 
agency to revise its strategy for acquiring and approving STARS, which 
contributed to STARS' overall cost growth of $500 million and added 3 
years to the schedule.

FAA also did not always sufficiently involve technical experts early in 
its approval process for 2 additional systems that we reviewed. For 
example, FAA did not obtain technical expertise on how to resolve the 
integrity requirement of WAAS, a navigation system for aviation that 
augments the Global Positioning System (GPS), until late in the design 
and development phase.[Footnote 15] FAA acknowledges that the agency's 
in-house technical expertise was not sufficient to address the 
technical challenges of WAAS. Initially, FAA and the contractor 
believed they could meet the WAAS integrity requirement to alert the 
pilot in a timely manner when the system should not be used. However, 
although WAAS was being developed by an integrated product team that 
included representatives from several FAA offices, the team did not 
function effectively in resolving issues related to meeting an 
important functional requirement to alert the pilot in a timely manner 
when the system should not be used because of a possible error. 
According to FAA officials, the reason coordination did not occur was 
that the two offices had competing priorities that were not associated 
with WAAS' development. Consequently, in 2000, FAA convened the WAAS 
Integrity Performance Panel to help it meet the integrity requirement. 
The WAAS Integrity Panel worked for about 2-1/2 years before it came up 
with a solution to the integrity requirement. In addition, in August 
2000, the agency established an Independent Review Board, which is 
independent of the panel and included experts in satellite navigation 
and safety certification, to oversee the panel and evaluate the 
soundness of its efforts. According to a member of the WAAS Integrity 
Panel, if FAA had involved these technical groups immediately after the 
contract was awarded to Raytheon in 1996, these groups could have 
started devising a solution in 1996, rather than in 2000. This lack of 
technical expertise contributed to a 6-year delay in WAAS' 
commissioning and a $1.5 billion increase in its development costs from 
the 1994 baseline.[Footnote 16]

FAA also did not fully engage technical experts early in the approval 
process of LAAS, a precision approach and landing system that will 
augment GPS. According to FAA officials, meeting the LAAS integrity 
requirement to alert the pilot in a timely manner when the system 
should not be used is perhaps the most difficult part of approving this 
system for safe use in the national airspace system. According to the 
Department of Transportation's Inspector General, although FAA had a 
LAAS Integrity Panel in place since 1996 to assist with its research 
and development activities, the panel was not formally tasked with 
resolving LAAS' integrity issues. According to one satellite navigation 
expert and the Department of Transportation's Inspector General, 
focusing the LAAS Integrity Panel on resolving the integrity 
requirement early in the approval process may have enabled FAA to 
develop a quicker solution.[Footnote 17] In 2003, FAA focused the LAAS 
Integrity Panel on developing a solution to meet the integrity 
requirement. However, FAA and another satellite expert maintain that 
the technical complexity of this problem is the main reason that LAAS 
is not commissioned. According to FAA officials, the need to validate 
integrity requirements and further software development has resulted in 
FAA placing LAAS in its research and development program and suspending 
funding for fiscal year 2005.

In contrast, FAA faced fewer schedule and cost problems in approving 
ASDE-X for use in the national airspace system. This was, in part, 
because FAA included stakeholders early and throughout the approval 
process and because program managers had strong technical expertise. 
The ASDE-X program office brought in stakeholders, including 
maintenance technicians and air traffic controllers, during the concept 
of operations phase and continued to involve them during requirements 
setting, design and development, and test and evaluation. FAA also 
brought ASDE-X stakeholders together at technical meetings to provide 
input on ASDE-X design and development, which allowed the ASDE-X 
program office to design a system that met requirements and 
incorporated stakeholders' needs. By obtaining the input of controllers 
and technicians at the beginning of the approval process, FAA was able 
to ensure that ASDE-X requirements were set at appropriate levels and 
not overspecified or underspecified. Some stakeholders commented that 
the program managers' strong technical expertise was one reason that 
ASDE-X's requirements were set appropriately. As a result, this system 
was initially commissioned only 5 months behind schedule and its cost 
increased moderately from $424 million to $510 million.

FAA Did Not Always Effectively Coordinate Its Certification and 
Approval Processes:

FAA did not always effectively coordinate its certification and 
approval processes for CPDLC, WAAS, and LAAS. Coordination between 
FAA's offices responsible for approval of ground systems and 
certification of aircraft equipment is becoming increasingly important 
given that more and more ATC systems have both ground systems and 
aircraft equipment. However, we found that coordination was not 
effective on CPDLC Build 1A, which allows pilots and controllers to 
transmit digital data messages directly between FAA ground automation 
systems and suitably equipped aircraft.[Footnote 18] In the interest of 
meeting the original cost and schedule estimates, FAA awarded the 
contract before it had a full understanding of system requirements. 
Requirements that specify how the ground system and aircraft equipment 
would operate together were not yet completed prior to award of the 
Build 1A contract. Consequently, changes needed to be made after the 
contract was awarded. New hardware requirements, software requirements, 
and other system requirement changes were added, which increased 
CPDLC's costs by $41 million, almost 61 percent of the total cost 
increases associated with CPDLC.

The lack of effective coordination among FAA offices responsible for 
approving WAAS also contributed to delays and increased costs in 
commissioning WAAS. Although WAAS was being developed by an integrated 
product team that included representatives from various FAA offices, 
the team did not function effectively in resolving issues related to 
meeting an important functional requirement to alert the pilot in a 
timely manner when the system should not be used because of a possible 
error. According to FAA officials, the reason coordination was not 
effective was because the two offices had competing priorities that 
were not associated with development of WAAS. Consequently, it was not 
until September 1999, when the aircraft certification office became 
fully involved, that FAA recognized that its solution to meet WAAS' 
integrity requirement was not sufficient and that it did not have the 
technical expertise needed to develop a solution. This lack of 
coordination contributed to a 6-year delay in WAAS' commissioning and a 
$1.5 billion increase in its development costs.

LAAS is another example of how FAA did not effectively coordinate its 
efforts. For example, FAA's Office of Regulation and Certification 
completed the design and production approval of LAAS aircraft equipment 
without effectively coordinating with the offices responsible for 
acquisition to determine the consequences of certifying aircraft 
equipment before approval of the associated ground system. According to 
an FAA official, once the Office of Regulation and Certification has 
given design and production approval to the LAAS aircraft equipment, it 
is not possible to make a change to the requirements for the aircraft 
equipment so that they are better integrated with the associated LAAS 
ground system. Consequently, LAAS ground system developers may have to 
make more costly and time-consuming changes to the ground system than 
would have been necessary if the Office of Regulation and Certification 
and acquisitions offices had coordinated their efforts.

FAA Did Not Always Prepare Accurate Estimates of the Amount of Time 
Needed to Meet Complex Technical Requirements:

We have reported in the past that when FAA attempts to combine 
different phases of system development in an effort to more quickly 
implement the systems to meet milestones, it repeatedly experiences 
major performance shortfalls and rework, which leads to schedule delays 
and cost increases.[Footnote 19] We found that WAAS, STARS, and LAAS 
all experienced delays and cost increases in part because FAA did not 
prepare accurate estimates of the amount of time needed to meet complex 
technical requirements, leading to an accelerated schedule that 
sometimes failed to include activities such as human factors 
evaluations and technical expert consultations. For example, in 1994, 
in response to the concerns of government and aviation groups, FAA 
accelerated implementation of WAAS milestones from 2000 to 1997. FAA 
planned to develop, test, and deploy WAAS within 28 months, an 
unrealistic goal given that software development alone was expected to 
take 24 to 28 months. It was not until July 2003, over 6 years later, 
that FAA was able to commission WAAS for initial operating capability. 
The accelerated schedule contributed to the 6-year delay in the 
commissioning of the system because the schedule itself was unrealistic 
and additional design work needed to be completed. During that time, 
the cost to develop the system increased about $1.5 billion, and the 
system has yet to meet its original performance goal of providing 
pilots with the ability to navigate down to 200 feet during their 
approach to the runway.

FAA also accelerated the schedule for STARS in 1995. FAA's approach to 
commissioning STARS was oriented to rapid deployment to meet critical 
needs for new equipment. To meet these needs, FAA compressed its 
original development and testing schedule from 32 to 25 months. 
Consequently, this acceleration in schedule left only limited time for 
human factors evaluations and, according to FAA officials, contributed 
to STARS' overall cost growth of $500 million and added 3 years to the 
first deployment because the agency had to revise its strategy for 
acquiring and approving STARS.

Although FAA had not developed a solution for meeting the integrity 
requirement, FAA also accelerated the LAAS schedule in 1999 by setting 
system milestones before completely designing the system. FAA 
originally planned to deploy LAAS in 2002 but has since moved it to 
fiscal year 2009 because the system's software development is not 
complete and a solution for meeting LAAS' integrity requirements has 
yet to be developed.

RTCA and the Aerospace Commission Found Challenges with FAA's Process 
for Approving Ground Systems and Certifying Aircraft Equipment:

RTCA and the Aerospace Commission also identified challenges with FAA's 
process for approving ground systems and certifying aircraft equipment. 
In 1998, at the request of the FAA Administrator, RTCA reviewed FAA's 
certification/approval process to determine if it could be made more 
responsive to the changing state of aviation, including its more 
integrated technologies. RTCA found that FAA's ground system approval 
process and aircraft equipment certification process took too long and 
cost too much, and RTCA made several recommendations to improve the 
processes. For example, in 2001, RTCA recommended that FAA implement a 
coordinated approval process that, among other things, would ensure 
that all stakeholders, including those outside FAA's program offices, 
participate in all phases of the approval process. Specifically, 
similar to our finding that the FAA offices that had responsibility for 
approving ground systems and certifying aircraft equipment did not 
always effectively coordinate their efforts, RTCA found that there was 
a need for better internal FAA communication and coordination, 
including the establishment of an organizational focal point to provide 
coordinated responses to all matters related to ground systems and 
aircraft equipment. RTCA also found that there was a need for an 
earlier and better exchange of information between FAA and those 
involved in the approval and certification processes from outside FAA, 
such as manufacturers of aircraft equipment.[Footnote 20]

In 2000, Congress asked the Commission on the Future of the U.S. 
Aerospace Industry to study the health of the aerospace industry and 
identify actions that the United States needs to take to ensure the 
industry's health. As part of this study, the Aerospace Commission 
reviewed FAA's certification process for aircraft equipment and made 
recommendations. The Aerospace Commission found that FAA's 
certification of new aircraft technologies has become uncertain in 
terms of time and cost and recommended that FAA's regulatory process be 
streamlined to enable the timely development of regulations needed to 
address new technologies. According to the Aerospace Commission, 
instead of focusing on rules and regulations that dictate the design 
and approval of equipment, FAA should focus on certifying that 
manufacturing organizations have safety built into their processes for 
designing, testing, and ensuring the performance of an overall system. 
The commission believed that such an approach would allow FAA personnel 
to better keep up with technological progress by becoming less design-
specific and more safety-focused.

FAA Has Taken Action to Improve Its Process for Approving ATC Systems:

FAA has taken action to address two of the three management challenges 
that we identified. However, FAA has not taken action to ensure that 
all stakeholders, such as air traffic controllers, maintenance 
technicians, technical experts, and industry representatives, are 
involved throughout the ground system approval process. FAA has also 
taken some action to address recommendations made by RTCA and the 
Aerospace Commission. Examples of some of the actions FAA has taken 
that address the management challenges that we found as well as RTCA 
and Aerospace Commission recommendations are discussed below:

* Coordinating FAA's acquisitions offices and Office of Regulation and 
Certification efforts for approving systems with ground and aircraft 
components: FAA officials believe that the agency's new Safety 
Management System, which is designed to formalize the agency's safety 
process, will also improve coordination among FAA internal stakeholders 
once it is implemented. FAA stated that coordination would improve 
because as part of the new Safety Management System the agency plans to 
realign its organizational structure to create a formal link between 
the Air Traffic Organization and the Office of Regulation and 
Certification. Within the Office of Regulation and Certification, there 
is the newly created Air Traffic Safety Oversight Service, which 
oversees the safety operations of the Air Traffic Organization and 
collaborates with the Air Traffic Organization's Safety Services. In 
addition, according to FAA officials, both ground systems and aircraft 
equipment will be more consistently assessed for their effect on safety 
as safety terminology is standardized. FAA expects full implementation 
to take 3 to 5 years. We are reserving judgment on whether this change 
will fully address the challenge because of the early state of this 
effort and because FAA's problems with internal coordination when 
approving ATC systems are long-standing. In addition, because FAA has 
historically faced internal and external coordination challenges in 
approving ATC systems for safe use in the national airspace, we believe 
that as FAA moves forward with the agency's new Safety Management 
System, it should, in the interim, develop plans that describe how both 
internal and external coordination will occur on a system-specific 
basis. In addition, plans to include external stakeholders are 
particularly important since the Safety Management System is not 
intended to address this challenge.

* Estimating the amount of time needed to meet complex technical 
requirements: During the development of WAAS and STARS, FAA adopted an 
incremental approach to developing and testing these systems to get 
them back on track, which is referred to as the "build a little, test a 
little" or spiral development approach. For example, to get WAAS back 
on track, FAA decided to take a more incremental approach to 
implementing the new navigation system--focusing more on the successful 
completion of research and development before starting system approval. 
In particular, FAA allowed time for collecting and evaluating data on 
key system performance requirements like the WAAS integrity requirement 
before moving forward. FAA officials acknowledged that the manner in 
which FAA decided to implement WAAS development before implementing 
this incremental approach was a high-risk approach and was a primary 
issue underlying the system's problems. Some aviation stakeholders 
believe this approach is advantageous because, although it can increase 
costs initially, money can be saved in the long run because the 
approach may help to avoid mistakes that are very costly to fix once a 
system has been developed. This approach also helps to ensure that the 
necessary building blocks of a system are tested along the way through 
the early and ongoing involvement of key stakeholders, those who will 
use and maintain the system. These stakeholders are key to identifying 
critical omissions and issues that could prevent a system from 
operating as intended.[Footnote 21]

As previously discussed, RTCA and the Aerospace Commission reviewed 
FAA's approval process and made a number of recommendations to improve 
it. FAA has taken some action to address these recommendations. For 
example:

* In response to RTCA's recommendation to implement a process in which 
the regulators and applicants come to an early and clear agreement on 
their respective roles, responsibilities, expectations, schedules, and 
standards to be used in certification projects, FAA issued The FAA and 
Industry Guide to Avionics Approval in 2001, which is intended to help 
FAA reduce the time and cost for the certification of aircraft 
equipment. This guide describes how to plan, manage, and document an 
effective, efficient aircraft equipment certification process and how 
to develop a working relationship between FAA and the applicant. In 
addition, as part of the 1999 FAA and Industry Guide to Product 
Certification, FAA encourages the manufacturers of aircraft equipment 
to develop a Partnership for Safety Plan that defines roles and 
responsibilities, describes how the certification process will be 
conducted, and identifies the milestones for completing the 
certification. A WAAS aircraft equipment manufacturer said that the 
certification of the WAAS aircraft equipment it developed went 
smoothly, primarily because of this up-front agreement with FAA. 
Although FAA's actions address the aircraft equipment certification 
process, it does not have a similar process for its ground system 
approval process.

* In response to RTCA's recommendation to establish an organizational 
focal point to provide one-stop service to users, industry, and other 
governments in all matters related to advanced ground electronics and 
aircraft equipment, FAA has completed a Web site that provides a broad 
range of information on the certification process for aircraft 
equipment. However, there is still no focal point to which industry can 
address questions about the approval process and be assured of getting 
a fully coordinated FAA answer.

* In response to the Aerospace Commission's recommendation to 
streamline its aircraft equipment certification process to ensure 
timely development of regulations needed to address new technologies 
and to focus on certifying that manufacturing organizations have built 
safety into their processes for designing, testing, and ensuring the 
performance of an overall system, FAA proposed creating an 
Organizational Designation Authorization program in January 2004. The 
program would expand the approval functions of FAA organizational 
designees,[Footnote 22] standardize these functions to increase 
efficiency, and expand eligibility for organizational designees.

Conclusions:

FAA did not always include stakeholders throughout the process for 
approving ATC systems for safe use in the national airspace system. 
Including stakeholders is particularly important because the new ATC 
systems are more integrated today than in the past and thus require 
more coordination among all the stakeholders, particularly FAA's Office 
of Regulation and Certification and the recently created Air Traffic 
Organization, but also between FAA and other stakeholders, such as 
technical experts, controllers, and maintenance technicians. When 
decisions regarding integrated ATC systems are made in isolation, they 
may contribute to the ineffective use of resources and time. We found 
that 3 of the 5 ATC systems we reviewed experienced cost growth and 
schedule delays, in part, because FAA did not always involve all 
necessary stakeholders, such as controllers and technical experts, 
throughout the approval process. In 2001, RTCA recommended that FAA 
implement a coordinated approval process that, among other things, 
would ensure that all stakeholders, including those outside FAA's 
program offices, participate in all phases of the approval process. We 
agree with RTCA's recommendation, which FAA has not fully implemented, 
and believe that fully implementing it would help address some of the 
challenges we found with FAA's approval and certification processes.

In addition, although FAA's new Safety Management System and the 
planned alignment between FAA's Air Traffic Organization and Office of 
Regulation and Certification have the potential to improve FAA's 
internal coordination, FAA has just begun implementing these 
initiatives with full implementation 3 to 5 years away. FAA also has 
historically faced internal coordination challenges in approving ATC 
systems for safe use in the national airspace system as we found for 
each of the 3 integrated systems that we reviewed. We believe that the 
implementation of the Safety Management System, coupled with the new 
formal link between FAA's Air Traffic Organization and Office of 
Regulation and Certification, will give FAA the opportunity to improve 
its internal coordination among its offices that are responsible for 
ground system approval and aircraft equipment certification. However, 
the system will not be implemented until 3 to 5 years. Therefore, 
because of FAA's history of internal and external coordination 
challenges, such as the lack of effective coordination between FAA 
offices responsible for approving WAAS, which contributed to WAAS' cost 
increase of about $1.5 billion and schedule delays of 6 years, we 
believe that specific plans for improving coordination both internally 
and externally on a system-specific basis are needed now.

Recommendation for Executive Action:

To ensure that key stakeholders, such as air traffic controllers, 
maintenance technicians, and technical experts, outside FAA's 
acquisitions offices and Office of Regulation and Certification, are 
involved early and throughout FAA's ground system approval process and 
to ensure better internal coordination between FAA's offices 
responsible for approving ground systems and certifying aircraft 
equipment, we recommend that the Secretary of Transportation direct the 
Administrator of FAA to develop ATC system-specific plans early in the 
approval process that specify how and when the approving and certifying 
offices within FAA and other stakeholders, including controllers, 
maintenance technicians, technical experts, and industry 
representatives, will meet to ensure coordination.

Agency Comments:

We provided a draft of this report to the Secretary of Transportation 
for review and comment. FAA generally agreed with our findings and 
recommendation and provided technical corrections, which we 
incorporated as appropriate. FAA also commented that it has started to 
take actions to improve its coordination efforts for integrated ATC 
systems.

We are sending copies of this report to interested congressional 
committees, the Secretary of Transportation, and the FAA Administrator. 
We will also make copies available to others on request. In addition, 
the report will be available at no charge on the GAO Web site at 
[Hyperlink, http://www.gao.gov]. Should you or your staff have 
questions on matters discussed in this report, please contact me on 
(202) 512-2834 or at [Hyperlink, siggerudk@gao.gov]. GAO contacts and 
key contributors to this report are listed in appendix VII.

Sincerely yours,

Signed by: 

Katherine Siggerud: 
Director, Physical Infrastructure Issues:

[End of section]

Appendixes:

Appendix I: Objectives, Scope, and Methodology:

To complete our first objective, to describe FAA's process for 
approving air traffic control (ATC) systems for safe use in the 
national airspace system, we obtained and analyzed documents from the 
Federal Aviation Administration (FAA) and RTCA's[Footnote 23] 1999 
report that discussed FAA's process for certifying aircraft equipment 
and approving ground systems. We also interviewed FAA officials, 
contractors, industry experts, and unions representing air traffic 
controllers and maintenance technicians that are involved in approving 
ATC systems.

To complete our second objective, to describe the challenges FAA has 
faced approving ATC systems and how those challenges affected the cost, 
schedule, and performance estimates of the systems, we conducted case 
illustrations on 5 of FAA's 25 air traffic control systems that are 
currently receiving funding:

* Airport Surface Detection Equipment - Model X (ASDE-X),

* Controller-Pilot Data Link Communications (CPDLC),

* Local Area Augmentation System (LAAS),

* Standard Terminal Automation Replacement System (STARS), and:

* Wide Area Augmentation System (WAAS).

We selected these 5 systems because collectively they accounted for 
about 46 percent of FAA's ATC modernization costs in fiscal year 2002 
and 3 of the 5 systems are integrated--that is, they require the 
approval of the ground systems as well as aircraft equipment. To select 
the 5 case illustration systems, we used FAA's capital investment 
project data file. We met with knowledgeable FAA officials to discuss 
issues related to the accuracy and completeness of the data file, which 
was deemed adequate for the purpose of our work. We also met with 
knowledgeable FAA officials to determine the number of ATC systems from 
the data file that needed to be approved before entry into the national 
airspace system. For each of the case illustrations, we reviewed FAA 
documents, including acquisition program baseline reports, Joint 
Resource Council decisions, and briefing documents. We also reviewed 
GAO and Department of Transportation's Inspector General reports and 
testimonies. In addition, we interviewed officials from FAA program 
offices; RTCA; the General Aviation Manufacturers Association; the Air 
Transport Association; the Aircraft Owners and Pilots Association; 
NavCanada; Transport Canada; the MITRE Corporation; Boeing; Garmin; 
Rockwell Collins; contractors, including Honeywell, Raytheon, and the 
Sensis Corporation; industry experts; the WAAS Integrity Performance 
Panel; the LAAS Integrity Panel members; and unions representing air 
traffic controllers and maintenance technicians.

To compete our third objective, to describe actions FAA has taken to 
improve its processes for approving ATC systems, we interviewed 
representatives from FAA; RTCA; the Commission on the Future of the 
U.S. Aerospace Industry; aviation industry groups, including the 
General Aviation Manufacturers Association, the Air Transport 
Association, and the Aircraft Owners and Pilots Association; 
manufacturers of aircraft equipment, including Garmin and Rockwell 
Collins; Boeing; and contractors, including Honeywell, Raytheon, and 
the Sensis Corporation; industry experts; and unions representing air 
traffic controllers and maintenance technicians.

We conducted our review in Washington, D.C., from October 2003 through 
September 2004 in accordance with generally accepted government 
auditing standards.

[End of section]

Appendix II: Airport Surface Detection Equipment - Model X Case 
Illustration:

Background:

ASDE-X is an airport surface surveillance system that air traffic 
controllers use to track aircraft and vehicle surface movements. (See 
fig. 2.) ASDE-X uses a combination of surface movement primary radar 
and multilateration[Footnote 24] sensors to display aircraft position 
and vehicle position on an ATC tower display. According to FAA, the 
integration of these sensors provides accurate, up-to-date, and 
reliable data for improving airport safety in all weather conditions. 
ASDE-X was developed to prevent accidents resulting from runway 
incursions,[Footnote 25] which have increased since 1993. The number of 
reported runway incursions rose from 186 in 1993 to 383 in 2001. 
According to FAA, because air traffic in the United States is expected 
to double by 2010, runway incursions may pose a significant safety 
threat to U.S. aviation.

FAA expects that ASDE-X will increase the level of safety at airports 
and provide air traffic controllers with detailed information about 
aircraft locations and movement at night and in bad weather due to the 
(1) association of flight plan information with aircraft position on 
controller displays; (2) continuous surveillance coverage of the 
airport from arrival through departure; (3) elimination of blind spots 
and coverage gaps; and (4) availability of surveillance data with an 
accuracy and update rate suitable for, among other things, awareness in 
all weather conditions.

Figure 2: Airport Surface Detection Equipment - Model X:

[See PDF for image]

[End of figure]

Status:

In October 2003, FAA commissioned ASDE-X at Mitchell International 
Airport in Milwaukee, Wisconsin, for use in the national airspace 
system. ASDE-X came in close to its original schedule and cost 
baselines. The ASDE-X system was approximately 5 months over its 
original schedule baseline, but maintained its original performance 
baselines. In June 2002, FAA approved $80.9 million in additional 
funding to add ASDE-X at 7 additional sites. (See table 2.) FAA is 
currently scheduled to deploy ASDE-X at 25 U.S. airports over the next 
4 years and to update existing surface detection systems (i.e., ASDE-3) 
at 9 other facilities. FAA plans to introduce an upgraded ASDE-X system 
at T.F. Green Airport in Providence, Rhode Island, with deployment 
tentatively slated for the 4th quarter of 2004. FAA is also 
investigating whether to add ASDE-X at 25 airports that use ASDE-3 and 
Airport Movement Area Safety Systems.

Table 2: Cost and Schedule Estimate Changes to ASDE-X:

Dollars in millions; 

September 2001 (baseline); 
Estimated development costs: $424.3[A]; 
Initial operating capability: May 2003; 
Full operating capability: 2007.

June 2002 (upgrade); 
Estimated development costs: $80.9[B]; 
Initial operating capability: September 2004; 
Full operating capability: 2005.

October 2003 (in-service decision); 
Estimated development costs: $510.2[C]; 
Initial operating capability: October 2003; 
Full operating capability: 2007[D]. 

Source: GAO presentation of FAA data.

[A] Includes 25 operational ASDE-X sites, 4 support systems, and 1 
ASDE-3 upgrade.

[B] Includes 7 ASDE-3 site upgrades.

[C] The October 2003 cost estimate includes a $5 million congressional 
addition for Dulles Airport.

[D] Although the last approved baseline included the 2007 date for last 
deployment, internal and external reprogramming for other high-priority 
activities and budget decrements in fiscal years 2004 and 2005 will 
slip the last deployment to fiscal year 2009. The ASDE-X program office 
is preparing a baseline management notice to adjust the baseline.

[End of table]

FAA Faced Fewer Challenges in Approving ASDE-X:

Of the five systems we reviewed, FAA faced fewer schedule and cost 
challenges in approving ASDE-X for safe use in the national airspace 
system. This is partly because FAA included stakeholders early and 
throughout the approval process and because of the strong technical 
expertise of its managers. The ASDE-X program office brought in 
stakeholders, including maintenance technicians and air traffic 
controllers, beginning with the concept of operations phase and 
continued their stakeholder involvement through the requirements-
setting, design-and-development, and test-and-evaluation phases and 
then continued involvement throughout the deployment phase. For 
example, FAA obtained the input of controllers and technicians at the 
beginning of the approval process, which helped to ensure that ASDE-X 
requirements were set at appropriate levels and not overspecified or 
underspecified. Stakeholders pointed toward the strong technical 
expertise of the program's managers as a reason for the appropriate 
specification of ASDE-X's requirements. In addition, FAA brought ASDE-
X stakeholders together at technical meetings to provide input on ASDE-
X design and development, which allowed the ASDE-X program office to 
design a system that met requirements and incorporated stakeholders' 
needs.

However, FAA did experience some challenges in approving ASDE-X. In 
response to Congress' desire to deploy the system quickly, FAA 
attempted to accelerate ASDE-X's approval. However, FAA experienced 
problems in accelerating the approval when it awarded the contract 
before all requirements had been finalized.

Table 3 shows the major phases and time frames associated with the 
ASDE-X approval process.

Table 3: ASDE-X Ground System Approval Timeline:

Phase: Concept of operations; 
Date: May 1998.

Phase: Requirements setting: Final requirements document; 
Date: September 1999.

Phase: Requirements setting: Contract award (signed); 
Date: November 2000.

Phase: Design and development: Planned human factors requirements; 
Date: February 2001.

Phase: Design and development: Critical design review; 
Date: April 2001.

Phase: Design and development: Baseline change; 
Date: June 2002.

Phase: Design and development: Underdeveloped radars; 
Date: July 2002.

Phase: Test and evaluation: Development test; 
Date: March 2003.

Phase: Test and evaluation: Operational test and evaluation; 
Date: May 2003.

Phase: Test and evaluation: Independent operational test and 
evaluation; 
Date: August 2003.

Phase: Operational readiness; 
Date: October 2003.

Phase: Commissioning; 
Date: October 2003. 

Source: GAO presentation of FAA data.

[End of table]

[End of section]

Appendix III: Controller-Pilot Data Link Communications Case 
Illustration:

Background:

CPDLC will allow pilots and controllers to transmit digital data 
messages directly between FAA ground automation computers and suitably 
equipped aircraft. (See fig. 3.) CPDLC is a new way for controllers and 
pilots to communicate that is analogous to e-mail. The pilot can read 
the message displayed on a screen in the cockpit and respond to the 
message with the push of a key. In the future, this will alleviate 
frequency congestion problems and increase controller efficiency. One 
of the most important aspects of this technology is its intended 
reduction of operational errors from misunderstood instructions and 
readback errors. The initial phase (Build 1) consisted of four 
services: initial contact, altimeter[Footnote 26] setting, transfer of 
communication, and predefined instructions via menu text. The CPDLC 
program will ultimately develop additional capabilities in an 
incremental manner through further development stages. Originally, 
Build 1 was to be followed by Build 1A, which was designed to increase 
the CPDLC message set and include assignment of speeds, headings, and 
altitudes as well as a route clearance function.

Figure 3: Controller-Pilot Data Link Communications:

[See PDF for image]

[End of figure]

Status:

CPDLC was commissioned for initial daily use by controllers at Miami on 
October 7, 2002. This completed the stage called Build 1, which 
included four services. American Airlines is the CPDLC launch airline 
with about 25 aircraft operating in the Miami Center airspace. Further 
deployment of CPDLC has been deferred until about 2009 after the Joint 
Resources Council did not approve the program in April 2003. The 
council made this decision because it believed that the benefits of 
CPDLC did not outweigh the costs. A number of factors contributed to 
this decision. First, FAA had concerns about how quickly aircraft would 
install the new airborne equipment. Second, the approved program 
baseline was no longer valid as Build 1A investment costs had increased 
from $114.5 million to $181.7 million, while the number of locations 
decreased from 20 to 8 as shown in table 4. Third, CPDLC would add $83 
million to the operations account.

Table 4: Cost and Schedule Estimate Changes to CPDLC:

Dollars in millions; 

Baseline/Cost estimate year: 1999 (Build 1A); 
Estimated development costs[A]: $114.5; 
Initial operational capacity - Build 1: June 2002; 
Initial operational capacity - Build 1A: June 2005; 
Locations (after Build 1A-completion): 20.

Baseline/Cost estimate year: April 2003[B]; 
Estimated development costs[A]: $181.7; 
Initial operational capacity - Build 1: October 2002; 
Initial operational capacity - Build 1A: Undetermined; 
Locations (after Build 1A-completion): 8.

Source: GAO presentation of FAA data.

[A] CPDLC Build 1 costs were $52.2 million.

[B] FAA did not approve this cost estimate.

[End of table]

For fiscal year 2005, program officials requested $3 million for CPDLC. 
According to FAA, this amount would be suitable for shutdown of CPDLC 
at Miami, closeout of Build 1, and alternatives analysis for a follow-
on program. The contractor, ARINC, had been providing messaging service 
for Miami at no cost. However, the contract for this free service 
expired on June 30, 2004.

Challenges in Approving CPDLC:

Lack of full coordination between FAA's aircraft certification and 
acquisition offices, in which there would have been a full 
understanding of all requirements, compromised the schedule and cost of 
CPDLC. FAA's acquisitions office, in the interest of meeting the 
original cost and schedule estimates, awarded the contract before FAA 
had a full understanding of system requirements, including those of 
FAA's aircraft certification office. Requirements that specified in 
detail how the air and ground equipment would operate together were not 
yet completed prior to award of the Build 1A contract. The addition of 
CPDLC hardware and software requirements increased costs by $26 
million, 39 percent of CPDLC's Build 1A development cost growth. In 
addition, other system requirement changes after contract award 
increased CPDLC's baseline development cost estimate by another $15 
million. In total, these requirement additions increased costs by $41 
million, almost 61 percent of the total cost increases associated with 
CPDLC Build 1A. (See tables 5, 6, and 7 for timelines of CPDLC's ground 
system approval and aircraft equipment certification.)

Table 5: CPDLC Ground System Approval Timeline (Build 1):

Phase: Concept of operations (initial); 
Date: October 1991.

Phase: Requirements setting: Final requirements document; 
Date: October 1998; 
revised April 2003.

Phase: Requirements setting: Contract award; 
Date: January 1999.

Phase: Design and development: Critical design review; 
Date: September 2000.

Phase: Test and evaluation: Development test; 
Date: February 2002.

Phase: Test and evaluation: Operational test; 
Date: December 2001.

Phase: Test and evaluation: Independent operational test and 
evaluation; 
Date: Early assessment - March 2003.

Phase: Test and evaluation: Initial operating capability; 
Date: October 2002.

Phase: Operational readiness; 
Date: October 2002.

Phase: Commissioning (Build 1); 
Date: October 2002.

Source: GAO presentation of FAA data.

[End of table]

Table 6: CPDLC Ground System Approval Timeline (Build 1A):

Phase: Concept of operations (initial); 
Date: October 1991.

Phase: Requirements setting: Final requirements document; 
Date: November 2002.

Phase: Requirements setting: Investment analysis[A]; 
Date: July 2003.

Source: GAO presentation of FAA data.

[A] Program has been deferred since completion of the investment 
analysis.

[End of table]

Table 7: CPDLC Aircraft Equipment Certification Timeline:

Phase: Concept of operations (initial); 
Date: October 1991.

Phase: Requirements setting: Certification plan (American Airlines); 
Date: August 2000.

Phase: Design and production approval; 
Date: May 2001.

Phase: Installation approval; 
Date: May 2001.

Phase: Operational approval; 
Date: September 2002.

Source: GAO presentation of FAA data.

[End of table]

[End of section] 

Appendix IV: Local Area Augmentation System Case Illustration:

Background:

LAAS is a precision approach and landing system that will augment the 
Global Positioning System (GPS)[Footnote 27] to broadcast highly 
accurate information to aircraft on the final phases of a flight. LAAS 
is being developed specifically to provide augmentation to GPS 
satellites to support Category I, II, and III precision approach and 
landing capability[Footnote 28] to aircraft operating within a 20-to 
30-mile radius of an airport. LAAS approaches are to be designed to 
avoid obstacles, restricted airspace, noise-sensitive areas, or 
congested airspace. In addition, a single LAAS ground station is to be 
capable of providing precision approach capability to multiple runways. 
LAAS has both ground and air components. LAAS ground components include 
four or more GPS reference receivers, which monitor and track GPS 
signals; very high frequency transmitters for broadcasting the LAAS 
signal to aircraft; and ground station equipment, which generates 
precision approach data and is housed at or near an airport. (See fig. 
4.) LAAS users will have to purchase aircraft equipment to take 
advantage of the system's benefits.

Figure 4: LAAS Infrastructure:

[See PDF for image]

[End of figure]

Status:

FAA's fiscal year 2005 budget request eliminated funding for LAAS, 
which is being moved from the acquisition program into a research and 
development effort. LAAS was slated for a 2006 rollout, but the target 
has now been deferred until at least 2009. FAA officials said they will 
reconsider national deployment when more research results are 
completed.

Before FAA decided to suspend funding for LAAS in fiscal year 2005, the 
LAAS program office was negotiating with Honeywell to develop a plan 
for determining how to meet the integrity requirements for the LAAS 
Category I system. According to FAA officials, the LAAS program office 
will use the $18 million remaining in fiscal year 2004 to continue the 
LAAS Integrity Panel for developing the LAAS Category I system, to 
validate LAAS Category II/III requirements, and to solve radio 
frequency interference issues. The $18 million will last through 2005, 
and FAA's goal is to meet LAAS integrity requirement by September 2005. 
Because of the budget cuts in fiscal year 2005, the LAAS program office 
will not be developing a Category II/III prototype.

As shown in table 8, the LAAS Category I system was initially expected 
to be operational in 2002. However, FAA was unable to meet the 
milestone, primarily due to development and integrity requirement 
issues. According to FAA officials, the research needed to validate the 
integrity requirement of LAAS Category I is scheduled to be completed 
by September 2005. If funds are fully restored in fiscal year 2005, FAA 
officials said that a LAAS Category I system can be developed and 
deployed by fiscal year 2009.

Table 8: Cost and Schedule Estimate Changes to LAAS:

Dollars in millions; 

Baseline/Cost estimate year: January 1998 (baseline); 
Estimated development costs: $530.1; 
Initial operating capability: 2002; 
Full operating capability: To be determined.

Baseline/Cost estimate year: September 1999; 
Estimated development costs: $696.1; 
Initial operating capability: 2001; 
Full operating capability: To be determined.

Source: GAO presentation of FAA data.

[End of table]

FAA Faced Challenges in Approving LAAS:

FAA faced a number of challenges in approving LAAS for safe use in the 
national airspace system, including (1) its inability to meet LAAS' 
integrity requirement, (2) not always communicating with the contractor 
about what was required to satisfy LAAS ground system requirements, and 
(3) accelerating the LAAS schedule by setting milestones before 
designing the system.

According to Honeywell officials, meeting the integrity requirement has 
been perhaps the most difficult part of approving LAAS for safe use in 
the national airspace system. Under FAA's integrity requirement for 
LAAS, the system must alert the pilot with timely warnings when it 
should not be used. However, FAA has not been able to develop a 
solution to meet this requirement because it has not been able to prove 
that the system is safe during solar storms. According to FAA 
officials, one of the reasons that FAA has not been able to develop a 
solution to meet this requirement is that a solar storm's effect on the 
ionosphere has not been modeled. The modeling is scheduled for 
completion in September 2004, and it will be used to design a monitor 
for ionosphere anomalies that could be developed and deployed by fiscal 
year 2009.

FAA also did not always communicate with the contractor about what was 
required to satisfy LAAS ground system requirements. Initially, FAA was 
in a partnership with industry, including Honeywell and others, to 
develop a LAAS Category I precision approach and landing system, which 
has a 200-foot ceiling height and one-half mile visibility. FAA 
partnered with industry to develop LAAS because FAA would have to pay 
industry only if industry achieved preset milestones, such as an 
analysis of the LAAS system integrity requirement. However, the 
partnership was not able to develop a system that FAA believed would 
operate safely in the national airspace system. Consequently, FAA 
decided to acquire LAAS on its own. In April 2003, FAA awarded a 
contract to Honeywell to develop a LAAS Category I precision approach 
and landing system. At the time the contract was awarded, FAA believed 
that 80 percent of the LAAS was developed and met its ground system 
requirements based on a review of documents. However, 5 months later, 
after further review, FAA discovered that only about 20 percent of 
development was complete. Nevertheless, Honeywell believes it met 80 
percent of the LAAS requirements. Both parties attribute the 
disagreement to lack of communication about what was needed to satisfy 
the LAAS ground system requirements. In fiscal year 2005, FAA decided 
to suspend funding and placed LAAS into its research and development 
program due to a lack of software development and the inability of the 
system to meet the integrity requirement. According to FAA officials, 
the research needed to validate the integrity requirement of LAAS 
Category I is scheduled to be completed by September 2005. If funds are 
fully restored in fiscal year 2005, FAA believes that a LAAS Category I 
system can be developed and deployed by fiscal year 2009.

FAA also experienced challenges in approving LAAS because it 
accelerated the schedule in 1998 to meet system milestones before 
completely designing the system and developing a solution for meeting 
the LAAS integrity requirement. FAA originally planned to deploy LAAS 
in 2002 but had to subsequently delay deployment to 2006 because of 
additional development work, evolving requirements, and unresolved 
issues regarding how the system would be approved. Lack of a solution 
for verifying that its integrity requirement had been met and 
incomplete software development were significant approval issues facing 
the LAAS program.

Table 9 shows the major phases and time frames for approving the LAAS 
ground system.

Table 9: LAAS Ground System Approval Timeline:

Phase: Concept of operations (initial); 
Date: 1992.

Phase: Requirements setting: RTCA performance standards; 
Date: September 1998.

Phase: Requirements setting: Creation of LAAS Integrity Panel; 
Date: 1996.

Phase: Requirements setting: Establishment of LAAS government industry 
partnership; 
Date: 1999.

Phase: Requirements setting: Rebaseline #1; 
Date: September 1999.

Phase: Requirements setting: Integrity requirement concerns 
identified; 
Date: December 2001.

Phase: Requirements setting: Requirements document final; 
Date: June 2002.

Phase: Requirements setting: LAAS cost estimate change (Category I 
only); 
Date: April 2002.

Phase: Requirements setting: Contract award; 
Date: April 2003.

Phase: Design and development: Software development issues identified; 
Date: September 2003.

Phase: Design and development: Critical design review; 
Date: Not complete.

Phase: Test and evaluation: Development test; 
Date: Not complete.

Phase: Test and evaluation: Operational test and evaluation; 
Date: Not complete.

Phase: Test and evaluation: Independent operational test and 
evaluation; 
Date: Not complete.

Phase: Operational readiness; 
Date: Not complete.

Phase: Commissioning/Initial operating capability; 
Date: Not complete.

Source: GAO presentation of FAA and RTCA data.

[End of table]

Certification of LAAS Aircraft Equipment Has Been Affected by Delays in 
Ground System Approval:

LAAS aircraft equipment received design and production approval in 
August 2004. It still awaits installation approval. (See table 10.) 
Because LAAS' aircraft and ground components are linked, certification 
of LAAS aircraft equipment has been affected by delays occurring during 
ground system approval. For example, according to aviation industry 
officials, requirement additions on LAAS' ground system led to 
requirement additions on LAAS' aircraft equipment. According to 
aviation industry officials, the addition of requirements to the ground 
system increased the cost and time to develop aircraft equipment, which 
changed the calculation for industry about whether developing LAAS 
aircraft equipment was a worthwhile investment and discourages future 
investment in aircraft equipment that will modernize the national 
airspace system.

FAA's Aircraft Certification Office Needs to Coordinate Better with 
Acquisitions Offices:

FAA's aircraft certification office completed the design and production 
approval of LAAS aircraft equipment without coordinating with the 
offices responsible for acquisition to determine the consequences of 
certifying aircraft equipment before approval of the associated ground 
system. According to an FAA official, once the aircraft certification 
office has given design and production approval to the LAAS aircraft 
equipment, it is not possible to make a change to the requirements for 
the aircraft equipment so that they are better integrated with the 
associated LAAS ground system. Consequently, LAAS ground system 
developers may have to make more costly and time-consuming changes to 
the ground system than would have been necessary if the aircraft 
certification and acquisitions offices had coordinated their efforts.

Table 10: LAAS Aircraft Equipment Certification Timeline:

Phase: Concept of operations (initial); 
Date: 1992.

Phase: Requirements setting: LAAS minimum operating performance 
standards; 
Date: 1995 to 2001.

Phase: Requirements setting: LAAS technical standard order development; 
Date: March 2003.

Phase: Design and production approval; 
Date: August 2004.

Phase: Installation approval; 
Date: Not complete.

Phase: Operational approval; 
Date: Not required[A].

Source: GAO presentation of FAA data.

[A] FAA first approved the use of GPS for aviation navigation in 1993, 
so new aircraft equipment that uses GPS did not require a new 
operational approval.

[End of table]

[End of section]

Appendix V: Standard Terminal Automation Replacement System Case 
Illustration:

Background:

STARS is a joint Department of Transportation, FAA, and Department of 
Defense (DOD) program established under 31 U.S.C. 1535, the Economy 
Act, as amended, to replace aging FAA and DOD legacy terminal 
automation systems with state-of-the-art terminal ATC systems. The 
joint program is intended to avoid duplication of development and 
logistic costs while providing easier transition of controllers between 
the civil and military sectors. Civil and military air traffic 
controllers across the nation are using STARS to direct aircraft near 
major airports. FAA's goal for STARS is to provide an open, expandable 
terminal automation platform that can accommodate future air traffic 
growth and allow for the introduction of new hardware-and software-
based tools to promote safety, maximize operational efficiency, and 
improve controllers' productivity. FAA believes that STARS will 
facilitate efforts to optimally configure the terminal airspace around 
the country, exchange digital information between pilots and 
controllers, and introduce new position and surveillance capabilities 
for pilots. (See fig. 5.)

Figure 5: Standard Terminal Automation Replacement System:

[See PDF for image]

[End of figure]

Status:

In June 2003, FAA first commissioned STARS for use at the Philadelphia 
International Airport in Pennsylvania. Currently, STARS is fully 
operational at 25 FAA terminal radar control facilities and 17 DOD 
facilities. Under the Air Traffic Organization's new business model of 
breaking large and complex programs into smaller phases to control cost 
and schedule, STARS is a candidate for further deployment to about 120 
FAA terminal radar control facilities. As shown in table 11, in April 
2004, FAA changed STARS' cost and schedule estimates for the third time 
and now estimates that it will cost $1.46 billion to deploy STARS at 
the 50 most important terminal radar control facilities that provide 
air traffic control services to 20 of the nation's top 35 airports. The 
original baseline in February 1996 was $940 million for 172 systems. 
The April 2004 estimate is an increase of about $500 million for 122 
fewer systems (i.e., over 70 percent less) than originally planned.

Table 11: Cost and Schedule Estimate Changes to STARS:

Dollars in billions; 

Baseline/Cost estimate year: February 1996[B]; 
Estimated development costs[A]: $0.94; 
Projected date for first deployment of STARS: 1998; 
Projected date for last deployment of STARS: 2005; 
Number of FAA systems receiving STARS: 172.

Baseline/Cost estimate year: October 1999; 
Estimated development costs[A]: $1.40; 
Projected date for first deployment of STARS: 2002; 
Projected date for last deployment of STARS: 2008; 
Number of FAA systems receiving STARS: 188.

Baseline/Cost estimate year: March 2002; 
Estimated development costs[A]: $1.33; 
Projected date for first deployment of STARS: 2002; 
Projected date for last deployment of STARS: 2005; 
Number of FAA systems receiving STARS: 73.

Baseline/Cost estimate year: April 2004[C]; 
Estimated development costs[A]: $1.46; 
Projected date for first deployment of STARS: 2003; 
Projected date for last deployment of STARS: 2008; 
Number of FAA systems receiving STARS: 50.

Source: GAO presentation of FAA data.

[A] This estimate includes development costs only and does not include 
technology refresh and terminal automation enhancement.

[B] The February 1996 baseline included limited human factors 
evaluations and a basic commercial off-the-shelf configuration.

[C] The April 2004 baseline occurred after STARS' commissioning in 
June 2003 in Philadelphia, Pennsylvania.

[End of table]

FAA Faced Challenges in Approving STARS:

FAA faced challenges in approving STARS. Although controllers and 
technicians were involved in developing requirements for STARS prior to 
the 1996 contract award to Raytheon, the original approved acquisition 
plan provided only limited human factors evaluation from controllers 
and technicians during STARS' design and development phase. The 
acquisition approach was to employ a commercial off-the-shelf system 
with limited modifications, and the competition was limited to 
companies with already operational ATC systems. In 1997, FAA 
controllers, who were accustomed to using the older equipment, began to 
voice concerns about computer-human interface issues that could hamper 
their ability to monitor air traffic. For example, the controllers 
noted that many features of the old equipment could be operated with 
knobs, allowing controllers to focus on the screen. By contrast, the 
STARS commercial system was menu-driven and required the controllers to 
make several keystrokes and use a trackball, diverting their attention 
from the screen. The maintenance technicians also identified 
differences between STARS and its backup system that made monitoring 
the system less efficient. For example, the visual warning alarms and 
color codes identifying problems were not consistent between the two 
systems. In 1997, FAA, the National Air Traffic Controllers 
Association, the Professional Airways System Specialists, and Raytheon 
formed a team to deal with these computer-human interface issues. The 
team identified 98 air traffic and 52 airway facilities computer-human 
interface enhancements to address these issues.

FAA and Raytheon restructured the contract to address the technicians' 
and controllers' concerns. According to FAA, not involving controllers 
and maintenance technicians caused FAA to revise its strategy for 
approving STARS, which FAA estimates added $500 million and 3 years to 
the schedule. The original STARS cost estimate of $940 million included 
limited human factors evaluations and the use of a basic commercial 
off-the-shelf configuration. This acquisition strategy was replaced by 
an incremental development strategy that incorporated up front the 
majority of human factors considerations and additional functionality 
that were not included in the original cost estimate. This new 
acquisition strategy added years to the development schedule and 
significantly increased the system's requirements specifications. 
These additional requirements resulted in both cost and schedule 
growth. FAA's own guidance showed that limiting human factors 
evaluations will result in higher costs and schedule delays. Initially, 
it is more expensive (in terms of time and funding) to deal with human 
factors considerations than to ignore them. However, an initial human 
factors investment pays high dividends, in terms of costs and schedule, 
in later stages of acquisition when changes are more costly and 
difficult to make.

FAA also experienced challenges in approving STARS, partly, because of 
aggressive scheduling. FAA's approach to approving STARS was oriented 
to rapid deployment to meet critical needs. To meet these needs, FAA 
compressed its original development and testing schedule from 32 months 
to 25 months. This acceleration in schedule left only limited time for 
human factors evaluations and not enough time for involvement of 
controllers and maintenance technicians.

Table 12 shows the major phases and time frames associated with the 
STARS approval process.

Table 12: STARS Ground System Approval Timeline:

Phase: Concept of operations (initial); 
Date: 1993.

Phase: Requirements setting: Requirements setting occurred; 
Date: 1994.

Phase: Requirements setting: Contract award; 
Date: September 1996.

Phase: Design and development: System design review; 
Date: December 1996.

Phase: Design and development: Human factors issues identified; 
Date: 1997.

Phase: Design and development: STARS baseline change; 
Date: October 1999.

Phase: Test and evaluation: Development test (Philadelphia, Full Stars-
2 Plus); 
Date: January 2002.

Phase: Test and evaluation: Operational test and evaluation 
(Philadelphia); 
Date: August 2002.

Phase: Test and evaluation: Independent operational test and 
evaluation (Philadelphia); 
Date: January 2003.

Phase: Operational readiness/Commissioning (Philadelphia); 
Date: June 2003.

Source: GAO representation of FAA data.

[End of table]

[End of section]

Appendix VI: Wide Area Augmentation System Case Illustration:

Background:

WAAS is a GPS-based navigation and landing system. According to FAA, 
WAAS is to improve safety by providing precision guidance to aircraft 
in all phases of flight at thousands of airports and landing strips, 
including runways, where there is no ground-based landing capability. 
To use WAAS for navigation, an aircraft must be equipped with a 
certified WAAS receiver that is able to process the information carried 
by GPS and WAAS geostationary satellite signals. Pilots are able to use 
this information to determine their aircrafts' time and speed, and 
latitude, longitude, and altitude positions. WAAS currently consists of 
a network of 25 ground reference stations, 2 leased geostationary 
satellites, 2 master stations, and 4 uplink (ground earth) stations. 
The ground reference stations are strategically positioned across the 
United States to collect GPS satellite data. (See fig. 6.) WAAS is 
designed to improve the accuracy, integrity, and availability of 
information coming from GPS satellites and to correct signal errors 
caused by solar storms, among other things.

Figure 6: WAAS Architecture:

[See PDF for image]

[End of figure]

FAA expects that WAAS will improve the national airspace system by (1) 
increasing runway capability; (2) reducing separation standards that 
allow increased capacity in a given airspace without increased risk; 
(3) providing more direct en route flight paths; (4) providing new 
precision approach services; (5) reducing the amount of and simplifying 
equipment on board aircraft; (6) saving the government money due to the 
elimination of maintenance costs associated with older, more expensive 
ground-based navigation aids; and (7) providing vertical guidance in 
all phases of flight to improve safety.

Status:

In July 2003, FAA commissioned WAAS to provide initial operating 
capability for 95 percent of the United States. In July 2003, the first 
of the LPV[Footnote 29] approaches were provided whereby pilots could 
safely descend to a 250-foot decision height.[Footnote 30] As of August 
2004, there were about 20 LPV landing procedures published for WAAS. 
With over 4,000 runways needing them, much work still needs to be done 
to fully utilize the WAAS capability. FAA expects to have WAAS 
available in the rest of the country, with the exceptions of a few 
parts of Alaska, by the end of 2008 when it completes the addition of 
13 ground reference stations and 2 leased geostationary satellites. 
WAAS is not scheduled to achieve full (Category I) operating 
capability, the final phase of WAAS when pilots will be able to use it 
to navigate as low as 200 feet above the runway, until the 2013-2019 
time frame.[Footnote 31]

As shown in table 13, FAA changed WAAS' cost and schedule estimates for 
the third time in May 2004. According to FAA, the reasons for the May 
2004 rebaselining were that the system was not able to achieve full 
Category 1 capability and because of FAA internal and congressional 
budget cuts. Under the May 2004 baseline, FAA estimates that WAAS 
development costs will be about $2.0 billion, which is $1.5 billion 
higher than the 1994 estimated development costs. Also, FAA has not yet 
met some of its original performance goals, such as providing pilots 
with the ability to navigate as low as 200 feet above the runway. 
According to FAA, WAAS cannot easily achieve Category I as a single 
frequency system because the error sources caused by solar storms are 
difficult to correct without the use of a second civil aviation 
frequency in space, which is the responsibility of the Department of 
Defense. FAA, realizing the difficulty and risk associated with 
developing a single frequency Category I system, decided to wait and 
leverage the benefits of the White House policy to include the second 
civil frequency on the GPS satellite network. According to FAA, budget 
cuts and the decision to wait until the second civil frequency is 
placed on the GPS constellation have caused it to extend the timeline 
for reaching WAAS' full Category I operating capability to between 2013 
and 2019.

Table 13: Cost and Schedule Baseline Changes to WAAS:

Dollars in millions.

Baseline year: 1994; 
Estimated development costs: $509; 
Initial operating capability: June 1997; 
Full operating capability: December 2000.

Baseline year: January 1998; 
Estimated development costs: $1,007; 
Initial operating capability: August 1999; 
Full operating capability: December 2001.

Baseline year: September 1999; 
Estimated development costs: $1,683[A]; 
Initial operating capability: September 2000; 
Full operating capability: December 2006.

Baseline year: May 2004; 
Estimated development costs: $2,036[B]; 
Initial operating capability: July 2003; 
Full operating capability: 2013-2019.

Source: GAO presentation of FAA data.

[A] The September 1999 estimate for WAAS development does not include 
$1.3 billion in satellite service acquisition through 2020. In earlier 
estimates, satellite service acquisition costs were included in the 
cost of operating WAAS, not developing WAAS.

[B] The May 2004 estimate for WAAS development does not include $1.3 
billion in satellite service acquisition through 2028. In earlier 
estimates, satellite service acquisition costs were included in the 
cost of operating WAAS, not developing WAAS.

[End of table]

FAA Faced Challenges in Approving WAAS:

FAA faced challenges in approving WAAS ground and satellite components 
for use in the national airspace system, partly because of FAA's 
accelerated scheduling, lack of effective coordination between its 
aircraft certification office and acquisitions office, and technical 
challenges which resulted in a delay meeting the integrity requirement. 
FAA's challenges in approving WAAS began in 1994 when FAA accelerated 
the implementation of milestones, including moving up the commissioning 
of WAAS by 3 years. FAA originally planned to commission WAAS in 2000; 
however, at the urging of government and aviation industry groups in 
the 1990s, it decided to change WAAS' commissioning date to 1997. FAA 
tried to develop, test, and deploy WAAS within 28 months, despite the 
fact that software development alone was expected to take 24 to 28 
months. FAA also set system milestones before completing the research 
and development required to prove the system's capability. Although FAA 
attempted to accelerate the implementation of WAAS, it wasn't until 
July 2003, 6 years later, that it was able to commission WAAS with 
initial operating capability.

Lack of full involvement between FAA's aircraft certification members 
and the rest of the integrated product team contributed to delays in 
approving WAAS. For example, although an integrated product team, which 
included representatives from aircraft certification and acquisition 
offices, was developing WAAS, it was not until September 1999, when the 
aircraft certification office became fully involved, that FAA 
recognized (1) the difficulty of meeting the integrity requirement--
that WAAS must alert the pilot in a timely manner when the system 
should not be used--and (2) it did not have the technical expertise 
needed. According to FAA officials, the reason coordination did not 
occur was because the two offices had competing priorities, such as the 
day-to-day aircraft equipment certification activities not associated 
with the development of a new ATC system. This situation may have 
developed because FAA's aircraft certification organization is more 
accustomed to being involved after a project is developed, rather than 
actively participating throughout project development.

The need to meet WAAS' integrity requirement also hampered FAA's 
ability to approve WAAS for safe use in the national airspace system. 
In December 1999, FAA found that WAAS did not meet the agency's 
integrity requirement for precision approaches, and FAA recognized that 
it did not have the technical expertise required to resolve the issue. 
Therefore, in 2000, FAA established a team of satellite navigation 
experts, which was referred to as the WAAS Integrity Performance Panel 
and included representatives from the MITRE Corporation, Stanford 
University, Ohio University, and the Jet Propulsion Laboratory. 
Developing a solution to prove that the WAAS design met the integrity 
requirement added about 2 years and 4 months to the approval process 
and contributed to WAAS' cost growth. All of these challenges 
contributed to a 6-year delay in WAAS' commissioning and a $1.5 billion 
increase in its estimated total development costs through 2028, 
exclusive of operating and maintaining geostationary satellites, which 
were not part of WAAS' original 1994 baseline. Table 14 shows the major 
phases and time frames associated with approving WAAS' ground system.

Table 14: WAAS Ground System Approval Timeline:

Phase: Concept of operations; 
Date: June 1992.

Phase: Requirements setting: Operational requirements document; 
Date: June 1994.

Phase: Requirements setting: Original contract award; 
Date: August 1995.

Phase: Requirements setting: Current contract award; 
Date: May 1996.

Phase: Design and development: Critical design review; 
Date: December 1997.

Phase: Test and evaluation: Development test (failed); 
Date: December 1999.

Phase: Test and evaluation: WAAS Integrity Performance Panel formed; 
Date: January 2000.

Phase: Test and evaluation: Development test (passed); 
Date: September 2002.

Phase: Test and evaluation: Operational test and evaluation; 
Date: March 2003.

Phase: Operational readiness/Commissioning; 
Date: July 2003.

Source: GAO presentation of FAA and RTCA data.

[End of table]

FAA Did Not Experience Major Challenges in Certifying the Aircraft 
Equipment of WAAS:

In contrast to the challenges that it encountered during the approval 
of the WAAS ground system, FAA did not encounter major challenges with 
the certification of WAAS aircraft equipment, primarily because FAA had 
an up-front approval agreement with one of the first applicants, United 
Parcel Service Aviation Technology, through the creation and approval 
of a safety plan and a project-specific certification plan. Table 15 
shows the major phases and time frames associated with certifying the 
aircraft equipment of WAAS. Currently, WAAS GPS receivers have been 
certified and are available for use.

Table 15: WAAS Aircraft Equipment Certification Timeline:

Phase: Concept of operations; 
Date: June 1992.

Phase: Requirements setting: RTCA WAAS minimum operational performance 
standards (four major revisions); 
Date: 1994 to November 2001.

Phase: Requirements setting: WAAS technical standard orders (four major 
revisions); 
Date: May 1998 to September 2002.

Phase: Design and production approval: Data submitted for supplemental 
type certificate and technical standard order authorization; 
Date: June 2, 2003.

Phase: Design and production approval: Technical standard order 
authorization (United Parcel Service Aviation Technology); 
Date: June 13, 2003.

Phase: Installation approval - Type certificate/Supplemental type 
certificate (United Parcel Service Aviation Technology); 
Date: June 27, 2003.

Phase: Operational approval; 
Date: Not required[A].

Source: GAO presentation of FAA data.

[A] FAA first approved the use of GPS for aviation navigation in 1993; 
therefore, new aircraft equipment that use GPS did not require a new 
operational approval.

[End of table] 

[End of section]

Appendix VII: GAO Contacts and Staff Acknowledgments:

GAO Contacts:

Katherine Siggerud, (202) 512-2834 or [Hyperlink, siggerudk@gao.gov];  
Tammy Conquest, (202) 512-5234 or [Hyperlink, conquestt@gao.gov]. 
 
Staff Acknowledgments:

In addition to the individuals named above, other key contributors to 
this report were Geraldine Beard, Gerald Dillingham, Seth Dykes, David 
Hooper, Kevin Jackson, Gregg Justice III, Donna Leiss, and Kieran 
McCarthy.

(540057):

FOOTNOTES

[1] Ground systems are air navigation facilities that, among other 
things, aid in the guiding or controlling of flight, including the 
landing and takeoff of aircraft. For the purposes of this report, 
ground systems include the satellites that may be associated with them.

[2] Organized in 1935 and once called the Radio Technical Commission 
for Aeronautics, RTCA is today known just by its acronym. RTCA is a 
private, not-for-profit corporation that develops consensus-based 
performance standards for air traffic control systems. RTCA serves as a 
federal advisory committee and its recommendations are the basis for a 
number of FAA's policy, program, and regulatory decisions. In 1999, 
RTCA published its Final Report of the Task Force 4: Certification. In 
2001, RTCA published RTCA Task Force 4 - Certification Implementation 
Plans and Responsibilities.

[3] The Wide Area Augmentation System Integrity Performance Panel is a 
team of satellite navigation specialists formed in January 2000 to help 
FAA meet Wide Area Augmentation System's integrity requirement to alert 
the pilot in a timely manner when it should not be used. FAA's 
integrity requirement stipulates that the Wide Area Augmentation System 
cannot fail to warn pilots of misleading information that could 
potentially create hazardous situations more than once in 10 million 
approaches.

[4] The Local Area Augmentation System Integrity Panel is a team of 
satellite navigation specialists formed in 1996 but formally tasked in 
2003 to help FAA meet the Local Area Augmentation System's requirement 
to alert the pilot in a timely manner when it should not be used. FAA's 
integrity requirement stipulates that the Local Area Augmentation 
System cannot fail to warn pilots of misleading information that could 
potentially create hazardous situations more than once in 10 million 
approaches.

[5] FAA's Acquisition Management System was created in response to a 
statutory mandate in 1995 that required FAA to implement a new 
acquisition management system that is intended to provide for more 
timely and cost-effective acquisitions.

[6] FAA's Air Traffic Services and Acquisitions Offices have recently 
become part of FAA's newly created Air Traffic Organization.

[7] However, sometimes the need for a service or capability originates 
in the private sector.

[8] The Joint Resources Council consists of senior FAA executives who 
discuss and approve agency mission needs and investments in acquisition 
programs.

[9] A type certificate is issued when an aircraft design is certified 
to meet applicable airworthiness standards. A supplemental type 
certificate is issued when an applicant has received FAA's approval to 
modify an aircraft from its original design. A production certificate 
applies to a company's manufacturing process and states that company 
can produce products consistent with the approved design. 

[10] However, sometimes the need for a service or capability originates 
in the private sector.

[11] Requirements may include regulation-based requirements, 
performance standards in technical standard orders, and/or 
international requirements. 

[12] If a technical standard order does not exist for aircraft 
equipment, the applicant will be required to obtain design and 
installation approval under the type certificate or supplemental type 
certificate design approval process, which involves many of the same 
activities involved in the technical standard order authorization 
process. Upon completion of this phase, FAA issues a type certificate 
or supplemental type certificate for one type of aircraft. 

[13] GAO, Air Traffic Control: FAA's Modernization Efforts - Past, 
Present, and Future, GAO-04-227T (Washington, D.C.: Oct. 30, 2003); 
National Airspace System: Persistent Problems in FAA's New Navigation 
System Highlight Need for Periodic Reevaluation, GAO/RCED/AIMD-00-130 
(Washington, D.C.: June 12, 2000); and National Airspace System: Status 
of FAA's Standard Terminal Automation Replacement System, GAO-02-1071 
(Washington, D.C.: Sept. 17, 2002).

[14] Human factors evaluation examines how humans interact with 
machines and identifies ways to enhance operators' performance and 
minimize errors.

[15] GPS is a space-based, radio-navigation system consisting of a 
constellation of satellites and a network of ground stations used for 
monitoring and control. A minimum of 24 GPS satellites orbit the Earth 
at an altitude of approximately 11,000 miles, providing users with 
accurate information on position, velocity, and time of a GPS-equipped 
object, such as an aircraft, anywhere in the world and in all weather 
conditions.

[16] In addition, some development costs, such as required design 
changes discovered during early development, were not included in the 
1994 baseline. When these development costs were captured in the 1999 
baseline and then again in the 2004 baseline, there was a net increase 
in development costs of $1.5 billion through 2028. However, these costs 
do not include operating and maintaining geo satellites, which were not 
part of WAAS' original 1994 baseline and added an additional $1.3 
billion in development costs.

[17] Department of Transportation's Inspector General, FAA Needs to 
Reset Expectations for LAAS Because Considerable Work Is Required 
before It Can Be Deployed for Operational Use, AV-2003-006 (Dec. 16, 
2002). 

[18] Build 1A was the second CPDLC development stage, yet to be 
completed, that was designed to increase the CPDLC message set and 
include assignment of speeds, headings, and altitudes as well as a 
route clearance function. 

[19] GAO, National Airspace System: Problems Plaguing the Wide Area 
Augmentation System and FAA's Actions to Address Them, GAO/T-RCED-00-
229 (Washington, D.C.: June 29, 2000).

[20] RTCA, Final Report of the Task Force 4: Certification (1999) and 
RTCA Task Force 4 - Certification Implementation Plans and 
Responsibilities (2001).

[21] GAO-04-227T and National Airspace System: FAA Has Implemented Some 
Free Flight Initiatives, but Challenges Remain, GAO/RCED-98-246 
(Washington, D.C.: Sept. 28, 1998).

[22] Organizational designees perform functions for FAA to minimize 
FAA's administrative burden. 

[23] Organized in 1935 and once called the Radio Technical Commission 
for Aeronautics, RTCA is today known just by its acronym. RTCA is a 
private, not-for-profit corporation that develops consensus-based 
performance standards for ATC systems. RTCA serves as a federal 
advisory committee and its recommendations are the basis for a number 
of FAA's policy, program, and regulatory decisions. In 1999, RTCA 
published its Final Report of the Task Force 4: Certification. In 2001, 
RTCA published RTCA Task Force 4 - Certification Implementation Plans 
and Responsibilities.

[24] Multilateration is achieved through the strategic placement of 
sensors around the airport grounds to report the location of aircraft 
and vehicles. 

[25] A runway incursion is any occurrence in the airport runway 
involving an aircraft, vehicle, person, or object on the ground that 
creates a collision hazard or results in a loss of required separation 
between two aircraft during takeoff or landing. 

[26] An altimeter is an instrument for measuring altitude. 

[27] GPS is a space-based, radio-navigation system consisting of a 
constellation of satellites and a network of ground stations used for 
monitoring and control. A minimum of 24 GPS satellites orbit the Earth 
at an altitude of approximately 11,000 miles, providing users with 
accurate information on position, velocity, and time of a GPS-equipped 
object, such as an aircraft, anywhere in the world and in all weather 
conditions.

[28] Category I precision approach has a 200-foot ceiling/decision 
height and visibility of one-half mile. Category II precision approach 
has a 100-foot ceiling/decision height and visibility of one-quarter 
mile. Category III precision approach and landing has a decision height 
less than 100 feet down to the airport surface. 

[29] LPV is an acronym with no specific definition today but once stood 
for Lateral Precision Vertical.

[30] A ceiling or decision height is the height above the Earth's 
surface to the lowest layer of clouds or obscuring phenomena.

[31] Category I precision approach has a 200-foot ceiling/decision 
height and visibility of one-half mile. 

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