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NATCA President Patrick Forrey’s testimony on FAA Reauthorization Act 2009


The National Air Traffic Controllers Association (NATCA) is the exclusive representative of over 14,000 air traffic controllers serving the Federal Aviation Administration (FAA), the Department of Defense, and the private sector. In addition, NATCA represents approximately 1,200 FAA engineers, 600 traffic management coordinators, 500 aircraft certification professionals, agency operational support staff, regional personnel from FAA’s logistics, budget, finance, and computer specialist divisions, and agency occupational health specialists, nurses, and medical program specialists. NATCA’s mission is to preserve, promote, and improve the safety of air travel within the United States, and to serve as an advocate for air traffic controllers and other aviation safety professionals. NATCA has a long history of supporting new aviation technology, modernizing and enhancing our nation’s air traffic control system, and working to ensure that we are prepared to meet the growing demand for aviation services.

NATCA’s Recommendations for FAA Reauthorization

  1. Collective Bargaining: NATCA fully supports and endorses the provisions of the FAA Reauthorization Act of 2009, addressing the Federal Aviation Administration Personnel Management System. This section nullifies the imposed work rules (IWRs) and orders the FAA to return to the bargaining table to reach a mutually agreeable contract with NATCA. In order to prevent future disputes, the bill amends Title 49 to allow for, in the event of a bargaining impasse, the proposals to go through mediation and ultimately, binding arbitration.
  2. Realignment of Facilities and Services: NATCA supports the inclusion of comprehensive language in FAA Reauthorization that would ensure that all FAA realignment initiatives are considered in a collaborative environment and provide a specific operational benefit. NATCA supports the establishment of a workgroup of stakeholders, included in the FAA Reauthorization Act of 2009. This group must review all realignment proposals prior to the FAA beginning the realignment process and must include representatives of all of the affected bargaining units. Additionally, NATCA recommends that realignment be clearly defined.
  3. Staffing: NATCA fully supports and endorses the FAA Air Traffic Controller Staffing provision within the FAA Reauthorization Act of 2009, which authorizes a scientific study of the system’s needed level for air traffic controller staffing to be conducted by an objective third party. This language would allow the FAA, Congress, and NATCA to truly assess the current risk to the National Airspace System (NAS) and set benchmarks for resolving the staffing crisis.
  4. Modernization: NATCA supports the funding levels set aside in the FAA Reauthorization of 2009 to modernize the air traffic control system. The NextGen modernization project’s start was less than expected, as the plan lacked clearly defined goals, leadership, and had begun without including stakeholders in the process. NextGen’s success is highly dependent upon a cooperative environment for the development and implementation of new and pre-existing technology.
  5. Maintenance of Air Traffic Control (ATC) Infrastructure: It is imperative that the funding of NextGen does not come at the expense of the NowGen. During the previous administration, the FAA allowed existing facilities to fall into disrepair while focusing all its energy and budget on NextGen projects. While NATCA supports the modernization of the system, we also insist upon the maintenance of the system. FAA facilities and ATC infrastructure must be maintained in a manner that ensures the safety and security of FAA personnel and allows aviation safety professionals the tools they need to do their jobs to the high standard of excellence we expect and depend on.

The State of the Air Traffic Control Workforce

NATCA and the FAA began contract negotiations in July 2005 over a successor agreement to the 2003 extension to the parties’ 1998 collective bargaining agreement. The FAA unilaterally declared an impasse after only nine months of negotiations. In June of 2006, the FAA announced its unilateral imposition of work and pay rules on the air traffic controller workforce, which it ultimately implemented in September 2006. This action not only violated the FAA’s legal obligation to bargain in good faith, but it also violated fundamental principles of fairness. This action, in effect, eliminated collective bargaining rights for FAA employees.

The effects of the imposed work rules have been devastating, not only to the working lives of controllers, but to the safety and integrity of the National Airspace System. Prior to the imposed work rules, NATCA officials warned that imposing work rules would result in a mass exodus of controllers from the FAA workforce and would result in dangerously low staffing levels. NATCA’s predictions have proven accurate.

In the two fiscal years following the imposed work rules, 2,626 air traffic controllers left the FAA workforce through attrition. This excludes the estimated 730 controllers who left the workforce through promotions or transfers. Of those that left due to attrition, less than two percent had reached the mandatory retirement age of 56. Ninety-eight percent left the FAA before mandatory retirement.

The FAA now insists that this exodus had been long anticipated and that it was the result of nothing more than an increase in retirement eligibility. This, however, is not the case. In FY2008 there were 947 retirements and 442 resignations, removals, and deaths. Three months prior to the implementation of the IWRs, the FAA predicted there would be 645 retirements and 84 resignations, removals, and deaths in FY2008, approximately half of the actual attrition level.

As NATCA has previously testified, the gap between the FAA’s prediction and the actual attrition can be attributed directly to the IWRs and the adverse work environment that those rules created. These rules removed career advancement opportunities, established new pay bands that decreased controller wages by an average of 30 percent, reduced the availability and duration of rest periods, instituted unpopular changes to the annual leave policy, and created an adverse work environment without a viable process to appeal or address managerial abuse of authority.

Veteran controllers who are eligible to retire have, because of the new pay bands, already worked their three highest salary years that will determine their pensions. Combined with the deterioration of working conditions and a more acute fear of errors due to increased workload, all incentives for experienced controllers to stay on board until their mandatory retirement age have been removed. On the other end of the spectrum, new hires are experiencing the stress and challenge of air traffic control, coupled with poor treatment from management and B-Scale wages, and are choosing to leave the FAA in favor of careers in the private sector.

One former controller summed up the sentiments of many in his resignation letter to the FAA:

Under the FAA’s new imposed work rules I cannot justify staying with the Agency… I do not feel I can continue to work in an environment that is so vindictive, or for an employer who is more worried about the bottom line rather than safety. I cannot justify staying when I can return to a company that knows how and makes it a point to take care of its employees. My take home pay will go up, my quality of life will improve and my workload will decrease.


The staffing shortage has created an environment conducive to high levels of fatigue among air traffic controllers, as controllers are required to work excessive amounts of overtime and work on short-staffed shifts.

At Orlando International Tower and TRACON, for example, controllers were required to work an average of 558 hours of overtime per pay period in CY2008. If divided evenly among the fully certified controllers, each controller would have to work more than 14 additional hours per pay period – cutting available rest and recovery time almost in half. While moderate amounts of overtime can be absorbed into the system without noticeable effects on performance, excessive overtime introduces fatigue into the system. In order to absorb the fatigue-inducing effects of overtime, an individual controller must have sufficient time for recovery following a long week, while the workforce must be made up of non-fatigued controllers who can provide support during the shifts themselves. With the staffing shortage such as it is, this is impossible. In addition, excessive overtime negatively affects controllers’ quality of life and interferes with home life issues such as childcare, lowering the morale of the workforce.

The alternative to excessive overtime is to work each shift without proper staffing levels.

A short-staffed shift often means controllers are afforded fewer opportunities for rest and recovery during the shift itself. They are being required to work longer on position and given shorter rest periods. Although the FAA had, until recently, limited time on position to two hours based on the results of a Civil Aeronautics Medical Institute (CAMI) study, this limitation was removed when the imposed work rules were instituted and is ignored throughout the system. At Atlanta tower (ATL), controllers report that they are given exactly 20 minutes of break time, regardless of the length of time on position or the intensity of the traffic.

Not only are controllers working longer on position, but the workload during that time has increased as well. On a short-handed shift, managers reduce the number of radar assistants (RAs), increasing the workload for the controller working radar. A controller working without an assistant is responsible not only for communication with aircraft but also coordination with other controller positions and facilities, as well as updating flight progress information. Additionally, managers may be forced to combine positions, creating greater complexity by requiring each controller to monitor greater numbers of confliction points and an increased volume of aircraft. One recent internal FAA document reported that as many as 56.3 percent of errors in Eastern En Route facilities occur when there are combined sectors, combined Radar/RA positions, or both.

Hiring Alone Is Not Enough: Inexperience and the Training Backlog

Rather than taking meaningful steps to stem the flow of experienced personnel, the FAA simply began a massive hiring effort. As a result, trainees now make up an extremely high percentage of the workforce. As of the end of FY2008, trainees (excluding CPC-ITS, previously certified controllers training on a new area or facility) accounted for nearly a quarter of the controller workforce (22 percent). This exceeds what the Inspector General of the Department of Transportation recently reported experts to consider the safe upper limit for the system. In many facilities the situation is even worse, with 48 facilities exceeding 35 percent trainees.

Staffing shortages and high trainee ratios have a direct effect on the efficiency of training itself. With so many trainees, and a small and shrinking number of Certified Professional Controllers (CPCs), there are a limited number of controllers capable of providing training, creating a backlog of trainees. At Miami Center (ZMA), for example, trainees have had to wait up to sixteen months from to receive on the job training (OJT) due to the facility’s staffing shortage.

For the first time since the 1980s, trainees are being put directly into some of the most demanding and difficult terminal facilities after completing their classroom training at Oklahoma City. These facilities include Atlanta Hartsfield Jackson Tower (ATL), Atlanta TRACON (A80), Charlotte Tower (CLT), New York TRACON (N90), Dallas-Fort Worth Tower (DFW), San Francisco Tower (SFO), Southern California TRACON (SCT), and Northern California TRACON (NCT). These higher level facilities do not have training curricula designed to teach new hires aircraft types, airline identification and other basic fundamental air traffic control knowledge and skills. In the past, terminal trainees were placed in a lower-level tower to receive initial certification and would transfer to a higher-level facility as their careers and skills advanced. The imposed work rules, however, removed financial incentives for experienced controllers to transfer to more difficult facilities because many would actually take a pay cut with such a transfer. Because retirement eligible controllers are leaving in record numbers, staffing has become critical at these terminal facilities, forcing the agency to hire trainees with no previous air traffic control experience.

Even as these trainees certify, the air traffic control system is still left staffed by individuals with little to no experience. These new hires are the future of air traffic control and have tremendous potential, but they are denied the opportunity to learn from experienced controllers and are forced to shoulder too much of the air traffic control burden at this early stage of their careers.

Since the implementation of the imposed work rules, the FAA lost more than 46,000 years of air traffic control experience through retirements alone. Nearly one third (27 percent) of air traffic controllers in the FAA have less than five years experience, and 40 air traffic control facilities have more than half of its workforce composed of individuals with less than five years experience.

Implications for FAA Reauthorization: Fair Dispute Resolution

The human factors issues facing the FAA are caused largely by the imposed work rules of 2006. These imposed work rules have precipitated the high rate of attrition, which in turn has caused understaffing, fatigue, high trainee ratios, and inexperience. It is vital to stem this flow of experienced controllers so that the system may be allowed to recover. The critical steps in this process are removing the imposed work rules and ordering the FAA to return to the bargaining table under the terms and conditions of the 2003 collective bargaining agreement to reach a mutually agreeable contract with NATCA.

The FAA Reauthorization Act of 2009 would accomplish this task. It would nullify the imposed work rules and order the FAA to return to the bargaining table under the terms of the last mutually-agreed-upon contract. NATCA believes that this will reduce the rate of attrition for experienced controllers, allowing new hires the best possible opportunity to train with seasoned veterans and maintaining what is left of the experienced workforce to control air traffic while the workforce is replenished.

The FAA Reauthorization Act of 2009 also amends Title 49 to include a fair dispute resolution process for FAA contract negotiations. If, during future negotiations, the parties arrive at impasse, both parties’ proposals will be sent to mediation and ultimately binding arbitration. This time-tested and fair process is used for impartial dispute resolution in workplaces throughout the country. It will ensure that the air traffic control workforce will never again find itself working under an imposed set of working conditions and pay rules.

NATCA fully supports and endorses the dispute resolution section of the FAA Reauthorization Bill of 2009.

Realignment of Facilities and Services

Realignment – the consolidation, deconsolidation, or reorganization of FAA facilities and services – must be implemented only when such changes enhance operational services, provide continued or improved safety, support and facilitate modernization of the NAS, is cost affective, and the impact on stakeholders is addressed and mitigated. NATCA has supported realignment initiatives in the past because such plans served an operational need and were designed and implemented in a collaborative environment. During the past 20 years, the FAA has completed several successful realignments with NATCA’s full support, including the creation of combined TRACON facilities in Southern California, Northern California, and the Baltimore/Washington, D.C./Virginia (Potomac) area.

During the previous Administration, the FAA began to separate radar and tower air traffic services at several airports across the country without seeking input from stakeholders. The FAA continued to move forward on these initiatives despite serious outstanding concerns over the effect such changes would have on safety and doubts over the operational benefit. Of particular concern in these cases was the staffing shortage, loss of staffing flexibility, barriers to coordination, and the deterioration of controllers’ knowledge of operations.

At Memphis International Airport (MEM), the FAA conducted a study which found that a stand-alone TRACON at MEM would need to be staffed with 43 certified professional controllers (CPCs), while the tower would require 37. A split facility would therefore require a total of 80 CPCs. However the combined facility currently employs only 47 CPCs, less than 60 percent of what is necessary to operate a split facility. In general, split facilities require additional staffing, as there is a reduction in flexibility when the workforce is split. At Orlando International Airport (MCO), the split has left the tower with dangerous levels of inexperience; more than 50 percent of MCO tower controllers have five years of experience or less. When the facility was combined this percentage was reduced to 35 percent, which, while still very high, was less dangerous.

Additionally, controllers at combined tower/TRACON facilities must learn all aspects of operations required for safe and efficient arrivals and departures. Controllers therefore understand how their actions at one position effect the operation of adjacent positions, enabling them to optimize their performance for both safety and efficiency. When facilities are split this knowledge is lost. Not only will new trainees be denied the opportunity to train on all aspects of the operation, they will not even have the opportunity to observe operations at other sectors.

For Miami and Philadelphia, NATCA offered an alternative configuration which enabled the facility to simultaneously maintain the advantages of a combined facility while reducing training time. After congressional and public pressure forced the FAA to review this alternative configuration the FAA ultimately agreed that the proposed configuration would resolve the issues at-hand without creating additional safety risks. This sudden course correction revealed the need for a thorough and open selection and review process for FAA facility realignment initiatives.

The FAA has an obligation to involve members of Congress, the public, airport operators, pilots, controllers, and other stakeholders in the decision-making, planning, and implementation process of any agency effort that could affect the safety and efficiency of the airspace. Regrettably, the agency has chosen to exclude stakeholders from the process, ignore their concerns, and inform the public only after its decision has been made. This go-it-alone method allows the FAA to remain ignorant of authentic and substantial inadequacies in the plans.

This is why NATCA supports the inclusion of comprehensive language in FAA Reauthorization that would ensure that all FAA realignment initiatives are considered in a collaborative environment and provide a specific operational benefit. We support the section in the Reauthorization Act of 2009 that requires the establishment of a workgroup of stakeholders to review all realignment proposals prior to the FAA beginning the realignment process. Representatives of all of the affected bargaining units must be included in this workgroup and realignment must be clearly defined.

Establishing Scientific Staffing Standards

In 1998 the FAA and NATCA agreed upon the optimal number of controllers for each facility based on a scientific study that factored in time-and-motion studies, sector complexity and workload, number of operations on the 90th percentile day, and relevant non-operational activities (i.e. training, annual/sick leave). Although the number of operations is similar to that of 1998 the FAA has abandoned these standards in favor of staffing ranges concocted to conceal the severity of the controller staffing shortage.

As part of its 2007 Controller Workforce Plan the FAA established staffing ranges for each air traffic control facility, which it modified slightly in 2008. Rather than basing its staffing goals on an accurate and precise scientific assessment of each facility’s requirements for safe operation, the FAA has designed these ranges in order to deliberately mislead stakeholders about the staffing crisis currently facing the air traffic control system in this country. They were also designed in order to meet specific budget goals, with regional directors identifying the number of air traffic control positions it could fund at each facility and remain within its fixed budgets. NATCA has reason to believe that the FAA’s official staffing ranges were engineered by the Air Traffic Organization (ATO) finance office, rather than the ATO safety office, based on a memo written by the workforce staffing manager, Jodi McCarthy.

The FAA attempts to justify this budget-based staffing standard by presenting a pseudo-scientific justification for its staffing numbers in its controller workforce plan. The FAA’s reasoning is based on an average of the following:

  1. Scientific Data – The FAA does not specify which study this refers to, who conducted it, or whether the study was conducted by an unbiased third party. It has thus far refused to provide NATCA with the details of the study parameters or the results.
  2. Current staffing at peer facilities – As the entire system is suffering the same staffing shortage, peer facilities will be equally understaffed. Therefore using these as a basis of comparison yields a dangerously low standard.
  3. Past staffing lows – The FAA misleadingly refers to this comparison as the past year of “highest productivity.” However, it goes on to define productivity as the highest number of operations per controller – or the year when the fewest controllers were relied upon to control the largest amount of traffic – without taking into account error rates, delays, or effect on the workforce. By using this definition of productivity the FAA is selecting a dangerously low staffing number as a standard again.
  4. Managers’ advice – The FAA misleadingly refers to this as “service unit input.” This input did not include input from NATCA and came entirely from within FAA management ranks who are under pressure to conceal the extent of the staffing shortage and assure Congress and the flying public that all is under control. Therefore this too is likely to yield a dangerously low and inaccurate estimate of needed staffing.

In the summer of 2008 the FAA acted in a way that corroborated NATCA’s claims of the invalidity of these staffing ranges by offering significant relocation incentives to controllers to transfer to many facilities throughout the country. These incentives included increases to base pay, bonuses, relocation payments, and allowed controllers to remain above the new pay bands, contrary to transfer procedure outlined in the imposed work rules. Yet in every case where such incentives were offered, current controller staffing is within – or in some cases even above – the FAA staffing ranges (See table 1). If FAA’s staffing ranges were accepted as valid it would appear as if the agency is offering lucrative incentives to transfer controllers to well-staffed, even overstaffed, facilities. The truth however, is that the facilities are indeed severely understaffed.

NATCA fully supports and endorses the language in the FAA Reauthorization Act of 2009 that authorizes a scientific study of the system’s air traffic controller staffing to be conducted by an objective third party. This language allows the FAA, Congress, and NATCA to truly assess the current risk to the NAS and set benchmarks for resolving the staffing crisis.

Facilities with Transfer Incentives Summer 2008
Facility Name FAC
Total On
Atlanta TRACON A80 93 86-105 104
Atlanta ATCT ATL 50 42-52 55
Chicago TRACON C90 99 82-100 101
Charlotte ATCT CLT 79 68-84 74
Cincinnati ATCT CVG 78 59-73 86
Detroit TRACON D21 48 47-57 71
Spokane ATCT GEG 30 23-28 32
Green bay ATCT GRB 25 20-24 22
Greer ATCT GSP 21 16-20 18
Houston TRACON I90 77 69-85 76
Indianapolis ATCT IND 43 42-52 56
Los Angeles ATCT LAX 46 39-47 47
Milwaukee ATCT MKE 48 38-46 51
New York TRACON N90 223 176-215 270
O’Hare ATCT ORD 69 56-68 71
Norfolk ATCT ORF 42 34-42 UNK
Potomac TRACON PCT 168 151-185 211
Raleigh ATCT RDU 44 38-46 48
Roanoke ATCT ROA 26 20-24 30
South Bend IND SBN 24 20-24 24
Souther California
SCT 221 194-237 261
Syracuse ATCT SYR 22 20-24 30
Tampa ATCT TPA 70 55-67 67
Within FAA
Above FAA


NATCA supports the modernization of the NAS, and applauds the generous funding provided for FAA Facilities and Equipment in the FAA Reauthorization Act of 2009. Such funding will accelerate the implementation of the Next Generation Air Transportation System (NextGen).

Our support of NextGen is not without conditions, however. Thus far, NATCA, like much of the industry community, has been disappointed by the FAA’s lack of clear direction for NextGen plans as well as the FAA’s continued exclusion of stakeholders from the planning and implementation of new technologies. NextGen will only be successful if it is done with complete participation and agreement from government, labor and industry groups from development through implementation. For example the technological initiatives of NextGen require extensive testing and NATCA members, with their current front-line experience, would be able to provide valuable contributions and insight during the testing phase.

During the late 1990s and into the early part of this decade, the FAA completed more than 7,100 projects to install and integrate new facilities, systems and equipment into the NAS. In addition, more than 10,000 hardware and software upgrades were completed. NATCA had representatives on over 70 modernization and procedure development projects. Under the Bush Administration, the FAA routinely avoided collaboration with NATCA on key issues and initiatives related to modernization and ultimately terminated the successful Controller Liaison Program, under which controllers provided crucial insight and guidance for the development and implementation of some of the most effective technological and procedural advancements including: Advanced Technologies and Oceanic Procedures (ATOP), Display System Replacement (DSR), User Request Evaluation Tool (URET), Voice Switching, Control System (VSCS), Reduced Vertical Separation Minimum (DRVSM), and Standard Terminal Automation Replacement System (STARS).

NATCA believes that the success of NextGen is dependent on this level of controller involvement. It is our hope that after the imposed work rules are removed and NATCA and the FAA reach a mutually agreeable collective bargaining agreement we can again return to an era of cooperation and collaboration that will best serve the needs of the NAS and the flying public.

Maintenance of Air Traffic Control Infrastructure

While NATCA supports the upgrade of air traffic control technology, it is imperative that the funding of NextGen not come at the expense of NowGen. During the previous administration, FAA facilities were allowed to fall into disrepair while the FAA pursued its ill-defined modernization goals.

According to a recent report by the Department of Transportation Inspector General, 59 percent of FAA facilities are beyond their 30-year design life. All en route centers are over 40 years old and falling into disrepair. Certain terminal facilities are also falling into unacceptable levels of disrepair – putting the health and safety of FAA employees at risk. For example, inspectors have confirmed the presence at Detroit Metropolitan Airport Tower and TRACON of stachybotrys, a toxic form of mold believed to be a contributory factor in health problems experienced by controllers at the facility (including cases of occupational asthma, as well as seven cancer diagnoses during the past six years.)

This level of deterioration is unacceptable. The FAA must repair and maintain existing air traffic control facilities in a manner that ensures the safety and security of FAA personnel and allows aviation safety professionals the tools they need to do their jobs to the high standard of excellence we expect and depend on.


NATCA commends the Aviation Subcommittee of the House Transportation and Infrastructure Committee for its demonstrated understanding of the important issues facing the nation’s aviation infrastructure as well as its efforts to quickly and thoroughly address these critical topics. NATCA is pleased with the bill’s approach to collective bargaining and dispute resolution at the FAA, as well as its attempts to ensure stakeholder inclusion in realignment efforts. We also fully support the authorization of a scientific staffing standard established by an unbiased third party. We are pleased with the level of funding for modernization, and urge the FAA not to neglect the maintenance of existing infrastructure while planning for the future. In NATCA’s view, the FAA Reauthorization Bill of 2009 is comprehensive and addresses many of the most important aviation issues, and we fully supports the bill’s swift passage.

[1] Based on payroll data provided to NATCA from the FAA.

[2] Based on the “A Plan for the Future 2006-2015: The Federal Aviation Administration’s 10-Year Strategy for the Air Traffic Control Workforce” June 2006.

[3] Employee resigned from Albuquerque ARTCC, in October 2006.

[4] According to NATCA records, there were 38 certified professional controllers (CPCs) at MCO.

[5] Weekly En Route (FY 08) Report May 30, 2008 Eastern Facilities, Federal Aviation Administration.

[6] Statement made by Calvin L. Scovel II, Inspector General, US Department of Transportation before the Senate Committee on Appropriations Subcommittee on Transportation, Housing and Urban Development and Related Agencies. April 17, 2008. “Key Safety and Modernization Challenges Facing the Federal Aviation Administration.”

[7] Interview with facility representative from ZMA.

[8] Calculation assumes 25 years experience for every retiree. Twenty-five years of services is the minimum for retirement eligibility for most air traffic controllers.

[9] FAA Document “Needs Comparison for 4 Splits: MTP Comparison for the 4 Splits”

[10] Based on Payroll data provided to NATCA from the FAA. This data is current as of the end of FY 2008.

[11] According to the FAA’s OPSNET database there were 45,394,027 instrument operations in FY2007 compared to 48,985,472 in FY1998 (93%).

[12] Letter from FAA Regional Administrator Christopher R. Blum, Central Region, to Congressman Dennis Moore. February 22, 2006.

[13] Untitled memo from Jodi S. McCarthy, ATO-T Finance, Manager, Workforce Staffing. Received February 28, 2007 on the topic of the staffing ranges featured in the 2007 Controller Workforce Plan.

[14] Transfer incentives identified on the FAA career opportunities website http://jobs.faa.gov/.

[15] Staffing based on payroll information provided to NATCA by the FAA. Total on-board staffing includes both CPCs and Trainees.

[16] Federal Aviation Administration “A Plan for the Future: The Federal Aviation Administration’s 10-year Strategy for the Air Traffic Control Workforce 2008-2017”

[17] National Air Traffic Controllers Association 2002 Air Traffic Modernization Tools.

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