Different aviation industry employers have distinct workforce needs and may require workers with specific skillsets depending on the type of work performed. The aviation maintenance workforce includes FAA-certificated mechanics and repairmen, as well as non-certificated workers. FAA-certificated mechanics inspect, service, and repair aircraft bodies (airframe) and engines (powerplant), and only they can approve an aircraft for return to service. FAA-certificated mechanics can earn an airframe rating, a powerplant rating, or an airframe and powerplant (A&P) rating. It can take between 1 and 3 years to obtain the required education or training to become certificated. If an FAA- certificated mechanic changes employers, the certificate remains valid. FAA-certificated repairmen service aircraft components and must be recommended for certification by their employer to perform specific tasks such as welding or painting. It can take more than a year to obtain the required experience or training to become certificated. FAA-certificated repairmen are employed by entities such as repair stations that are authorized by FAA to perform specific tasks. A repairman certificate is only valid at the employer for which it was issued. Non-certificated aviation maintenance workers include individuals who are supervised by certificated mechanics or repairmen in performing repair work. FAA maintains data on certificated mechanics and repairmen, including data on characteristics such as age and sex. FAA also maintains some data on non-certificated workers, such as the number employed by FAA- certificated repair stations, but neither the federal government nor the aviation industry maintains data on the total number of non-certificated aviation maintenance workers. Career pathways consist of education, training, and support services that enable individuals to obtain industry-relevant certification and employment. There are three distinct pathways to become eligible to take the FAA mechanic tests—military training and experience, AMT School, and practical, or civil work experience (see fig. 1). FAA collects data on the use of the different pathways to becoming a certificated mechanic. Individuals must pass the FAA mechanic tests to become certificated, regardless of the pathway they take to become eligible to take the tests. There are three tests—written, oral, and practical. FAA publishes testing standards for the oral and practical skills tests. Military training and experience. The Community College of the Air Force administers an FAA-approved A&P training program which consists of on-the-job training and various courses for military service members with certain experience. When service members successfully complete the program, the Joint Services Aviation Maintenance Technician Certification Council issues them a certificate of eligibility to take the FAA mechanic tests (see side bar). Aviation Maintenance Technician School. Individuals may also attend an FAA-approved AMT School to become eligible to take the FAA mechanic tests. FAA approves and oversees AMT Schools and it maintains enrollment and mechanic test pass-rate data for each school. The minimum curriculum requirements for these schools are currently prescribed in regulation. The regulation includes the subjects the curriculum must cover and the number of training hours students must complete to become eligible to take the FAA mechanic tests. Given that AMT School curriculum requirements are in regulation, FAA has in the past attempted to amend the requirements through the federal rulemaking process. Practical work experience. People can also become eligible to take the FAA mechanic tests by demonstrating practical, or civil work experience. Individuals may work under the supervision of a certificated mechanic for 18 months for either an airframe or powerplant certificate, or 30 months for an A&P certificate. Practical work experience includes apprenticeships, which combine on-the-job training with classroom instruction. For certificated repairmen, there is no prescribed test, though repairmen must demonstrate their practical experience or have completed formal training to be certificated. Avionics technicians also have no prescribed test, but may seek certain related certifications. The Standard Occupational Classification (SOC) system is a federal statistical standard used to classify workers into occupational categories for purposes of collecting, calculating, or disseminating data such as employment levels and pay. The SOC structure forms the basis for the occupational coding system used by BLS’ Occupational Employment Statistics survey and Current Population Survey. Aviation maintenance workers generally fall into the avionics technicians or the aircraft mechanics and service technicians occupational group (see fig. 2). Both occupational groups include certificated and non-certificated individuals. The most recent revision to the SOC was for 2018. In addition to the Department of Transportation (DOT) and FAA, several other federal agencies play a role in developing and maintaining a qualified aviation professional workforce. For example, we previously reported on related efforts administered by DOD, DOL, VA, and Education. These agencies provide either financial assistance for education or training in aviation maintenance related fields or administer programs that support career pathways to becoming an FAA-certificated mechanic or repairman. As of December 2018, about 295,000 individuals held a mechanic certificate and about 35,000 held a repairman certificate. The median age of FAA-certificated mechanics and repairmen was 54 years old, according to our analysis of the FAA data. Specifically, 52 percent were between the ages of 50 and 70 years old; 19 percent were between 39 and 49; and 19 percent were between 18 and 38. The remaining 10 percent were between the ages of 71 and 89 years old (see fig. 3). In comparison, about 23 percent of the overall workforce was age 55 or over according to BLS data as of 2018. Our analysis of FAA data also found that 3 percent of all aviation maintenance certificate holders were women as of December 2018. This percentage has not changed since we last reported on this workforce in 2014. In comparison, BLS data as of 2018 show that women made-up 47 percent of the total workforce. We were not able to analyze other demographic characteristics for these certificate holders, such as race or ethnicity, because neither FAA nor BLS collects these data. FAA data for 2015 through 2018 also provide some information on the education and work experience of certificated mechanics. These data show that attending AMT School was the most common pathway certificated individuals used to qualify for the FAA tests to become mechanics (see fig. 4). In addition, FAA data provide information on the number of newly certificated individuals and indicate that FAA certificated about 8,600 mechanics and repairmen on average each year for 2014 through 2018 (see fig. 5). BLS data project an annual average of 11,800 job openings in the United States from 2018-2028 for the aircraft mechanics and service technicians occupation due to growth and replacement, which include job openings for both certificated and non-certificated workers. The supply of workers to fill any open or projected job openings in the aviation industry, however, not only depends on the number of people qualified to do the work, but also their availability and willingness to work at a certain wage and under particular working conditions. While FAA data provide information on the number of mechanic and repairman certificate holders who are qualified to perform certain work, less is known about the number of them who are available and willing to work in the aviation industry. FAA data show there were approximately 330,000 certificated mechanics and repairmen as of December 2018, but FAA officials said this number likely overestimates the number of individuals working in the aviation industry. BLS data indicate 136,900 were employed in the aircraft mechanics and service technicians occupation in 2018, but it is not clear how many of those jobs were filled by FAA- certificated workers. In addition, it is unknown how many of the approximately 330,000 certificate holders are retired, deceased, or working in other industries. Individuals who obtain a mechanic certificate from FAA may never work in the aviation industry, or may begin their career in the aviation industry and leave for a job in another industry. Several stakeholders we interviewed said FAA-certificated mechanics possess certain skills that are transferrable to other industries and leave the aviation industry to work for other employers, such as amusement parks. Furthermore, officials explained that once certificated, there is no certification renewal requirement for mechanics. BLS publishes some data on pay for aircraft mechanics and service technicians, such as average hourly and annual wages. However, the occupational classification system BLS and other federal statistical agencies use for aircraft mechanics and service technicians does not distinguish between FAA-certificated and non-certificated workers. This is in part because workers are classified by the work they perform and not necessarily by certification or education, according to SOC classification system principles. As a result, it is difficult to determine employment characteristics such as pay for certificated workers, specifically. BLS data as of May 2018 show that annual wages for aircraft mechanics and service technicians ranged from about $37,000 to about $98,000. According to BLS officials, it is not uncommon for there to be a wide salary range across an occupation, as wages may vary depending on factors such as experience, education, and skills. A DOD official we interviewed also said that employers have told him that they pay certificated aviation maintenance workers more than non-certificated workers. BLS officials said they collected wage and employment data for certificated workers separate from non-certificated workers in employer surveys conducted between 2000 and 2012. However, officials said they stopped collecting these data in part because employers inconsistently reported them. Data limitations at the federal and state levels also make it difficult to determine the demand for certificated aviation maintenance workers. BLS occupational data. On the federal level, BLS occupational outlook data provide some information on potential future demand nationwide for aviation maintenance workers, but the data do not distinguish between certificated and non-certificated workers. As a result, the data provide limited detail about the demand for certificated workers, specifically. According to BLS data, total employment for the aircraft mechanics and service technicians occupation is projected to grow about 3 percent over the 2018 to 2028 time frame, which is slower than the average for all occupations. As previously mentioned, these data project an annual average of 11,800 job openings for this occupation from 2018 to 2028 due to job growth and replacement. DOL certification data. On its public website for career planning and job search, CareerOneStop, DOL provides information on certifications that are frequently mentioned in online job postings and considered to be in-demand. DOL also indicates in its online resources which certifications may draw on training and experience gained in the military. However, DOL does not track or publish data on the demand for occupational licenses, including federal licenses such as FAA’s A&P certification. DOL officials said currently there are no plans to expand the agency’s data collection to include information on the demand for occupational licenses. DOL officials added that for certain jobs that require licenses, the demand for the required licenses mirrors occupational demand for those jobs so collecting those data may not be as meaningful. Workforce Innovation and Opportunity Act plans. On the state level, Workforce Innovation and Opportunity Act plans, intended in part to outline states’ use of federal funds to help workers meet employers’ needs, provide some geographically-specific information on the demand for workers in the aviation industry. Our review of states’ most recent Workforce Innovation and Opportunity Act plans found that 19 states identified the aerospace and aviation industry as a targeted sector for development. However, only certain plans specifically mention the need for certificated mechanics; others refer to the aviation industry more broadly. Employers we interviewed had differing perspectives on potential growth in demand for aviation maintenance workers; some said they were experiencing difficulty finding enough workers to meet their needs, while others said they were not experiencing difficulty. While some stakeholders voiced concerns about the potential for a labor shortage, the selected labor market indicators we reviewed for aircraft mechanics and service technicians (unemployment, wages, and employment) from 2013 through 2018 were not all consistent with the existence of hiring difficulties. See appendix I for our analysis. Officials we interviewed from a regional airline said the majority of the airline’s certificated mechanics come to them directly after completing AMT School and that the airline was having a difficult time finding enough mechanics to fill 60 open full-time positions. On the other hand, officials we interviewed from a major airline said the airline rarely hires certificated mechanics right out of AMT School and that their employees typically come to them with a number of years of experience. The officials from the major airline said that they were not experiencing difficulty recruiting and retaining aviation maintenance workers, but noted that regional airlines may experience hiring difficulties first if there is a shortage of these workers because certificated mechanics often start their careers at regional airlines to gain practical experience before moving on to work at a major airline. Registered Apprenticeship Program Serving Underrepresented Populations The Department of Labor awarded the Connecticut Department of Labor Office of Apprenticeship Training a $1,550,000 grant to fund the Connecticut Apprenticeship Expansion Rx project, which targets the aviation industry, among others. The project aims to serve over 1,600 apprentices and provide underrepresented populations, including women, dislocated, and under- employed individuals an opportunity to acquire industry required credentials. Key partners include industry, educational institutions, and labor unions. Registered Apprenticeship Program for Airframe and Powerplant Mechanics As part of the State Apprenticeship Expansion grant, the Alaska Department of Labor and Workforce Development (DOLWD) is implementing registered apprenticeships in aviation, a relatively new industry in using the apprenticeship model. With the help of the U.S. Department of Labor Office of Apprenticeship in Alaska, two aviation occupations have been approved: Airframe & Powerplant Mechanic and Air Transport Pilot. The Alaska state Apprenticeship Coordinator is working closely with the U.S. Department of Labor Office of Apprenticeship and individual air carriers across Alaska to develop and implement registered apprenticeships for these occupations. Alaska DOLWD has approximately 12 mechanic apprentices and 2 air transport pilot apprentices with various air carrier employers. support Registered Apprenticeship Programs— employer-driven training opportunities that combine on-the-job learning with related classroom instruction. The program facilitates coordination among different stakeholders such as industry, states, and educational institutions to support apprenticeships and employment opportunities. DOL awarded almost $3.8 million in grants and contracts from 2014 through 2018 to promote these apprenticeships for aviation maintenance workers. For example, one grantee is aiming to serve underrepresented populations in the aviation industry, including women, and another is coordinating with industry to develop a registered apprenticeship program for certificated mechanics (see side bars). In addition, the United Services Military Apprenticeship Program, a DOL registered program, provides service members an opportunity to improve skills and qualify for employment in a recognized civilian trade, including as an A&P mechanic, upon completion of military service. VA’s Post-9/11 GI Bill Program. The Post-9/11 Veterans Educational Assistance Act of 2008 (Post-9/11 GI Bill) provides funding for veterans to pursue an approved program of education, including undergraduate and graduate degrees, non-college degree programs, apprenticeships, and on-the-job training. VA data show approximately $42 million in Post-9/11 GI Bill funds were awarded in fiscal year 2018 to 4,200 veterans enrolled in aviation maintenance post-secondary programs, which include programs at FAA-approved AMT Schools. Education’s financial assistance. Education provides billions of dollars in federal assistance to support students pursuing higher education, which may include training in aviation-related fields. We previously reported that in academic year 2011-2012, Education disbursed $918 million in federal grants to 142,708 recipients and $1.3 billion in federal loans to 114,564 recipients pursuing aircraft mechanic and avionics programs. DOT’s workforce development grant program. DOT is also developing a process for administering a workforce development grant program for aviation maintenance workers. Specifically, the FAA Reauthorization Act of 2018 included a provision for DOT to establish an aviation maintenance workforce development grant program. Once established, eligible entities such as aircraft repair stations, unions, educational institutions, and state or local governments may apply for grants. The program may provide grants for projects such as establishing new educational programs or scholarships for individuals seeking employment in the aviation maintenance industry and supporting service members transitioning into aviation maintenance related careers. In addition, FAA has taken steps to engage other key stakeholders on aviation workforce development initiatives. In September 2018, FAA sponsored an Aviation Workforce Symposium that included participants from industry, AMT Schools, and federal agencies such as Education and DOL. Discussion topics included building the pipeline of workers, maximizing efficiency in training, and promoting productive partnerships. Subsequent to the 2018 symposium, FAA established an Aviation Workforce Steering Committee in February 2019, in part to coordinate efforts across FAA to address various workforce related provisions included in the FAA Reauthorization Act of 2018. The steering committee finalized its charter in April 2019, and the charter states FAA’s intentions of developing productive partnerships with industry, government, and educational institutions to expand the pipeline of aviation safety professionals. As of October 2019, FAA was finalizing a working group structure to carry out the steering committee’s work that will focus on: (1) marketing/communications, (2) educational outreach, (3) training, and (4) partnerships. FAA officials also told us they plan to collaborate with other federal agencies moving forward, including Education, DOL, and DOD. For example, FAA and DOD officials said they are currently discussing options for streamlining pathways for service members with aviation maintenance backgrounds to move into civilian careers in aviation maintenance. According to a DOD official, streamlining pathways could increase the number of service members who become FAA-certificated mechanics and leverage the skills of the over 250,000 current service members with aviation maintenance backgrounds. Additional examples of states, industry employers, and AMT Schools coordinating or partnering to support the aviation maintenance workforce include: Career grants. One state we visited developed a career grant to align students’ programs of study with in-demand occupations in the state. The grant provides tuition assistance to in-state residents working toward selected certificates or degrees at eligible in-state colleges or universities, including aviation maintenance programs. Military pathway program. Officials from a regional airline we interviewed said the airline developed a military transition program to assist service members in preparing for the FAA mechanic tests. The airline funds 100 percent of the program cost, which according to officials is about $11,000 per person. As part of the program, airline officials told us they provide about $5,000 worth of tools to each participant. Training equipment and funding. Officials we interviewed from one school said they strategically opened their AMT program next to a major cargo airline so that students could benefit from employment opportunities there. The officials said the airline also benefits from the close proximity of the school in that it is able to leverage local talent, and the airline provides AMT School students with scholarships, technical support, and surplus equipment to use for training. In another example, officials from a major commercial airline told us the airline partners with over 40 AMT Schools and provides them with funding to improve operations and recruitment. Officials said the goal of the program is to ensure the airline has a pipeline of workers to fill any future job openings. Despite FAA’s recent efforts to coordinate with other federal agencies on expanding and streamlining pathways for aviation maintenance careers, we found that FAA does not routinely analyze, collect, or coordinate with other stakeholders on certain related data. Such activities could assist FAA in measuring progress toward meeting its workforce related objectives and inform strategic decisions for promoting the development of this workforce. For example, FAA’s strategic plan includes an objective on promoting the development of a robust aviation workforce. In addition, FAA’s Aviation Workforce Steering Committee charter emphasizes providing diverse populations, including youth, women, and minorities, with clear pathways into aviation careers to expand the talent pool from which both government and industry may recruit. However, neither the strategic plan nor the steering committee charter provides specific information on how FAA plans to select and measure any efforts it undertakes related to these objectives. Prior GAO work has emphasized that strategic workforce planning requires monitoring and evaluating progress toward goals, and federal internal control standards state that management should use quality information to achieve its objectives. We identified several areas in which improved data analysis, collection, or coordination could assist FAA in measuring progress and understanding how to target its resources in support of its workforce related objectives. Demographic data. FAA collects certain demographic data on its A&P certification application, such as the age and sex of individuals; however, FAA currently uses these data only to determine eligibility and issue certificates, according to FAA officials. These data could also be used to identify patterns or relationships, such as the trend in female certificate holders by pathway, which could be useful information as FAA aims to increase opportunities for women to pursue aviation maintenance careers. In addition, FAA does not currently collect data on the race and ethnicity of certificated individuals. Such data could provide additional information on the demographics of certificated individuals and help FAA or other stakeholders monitor the progress of any efforts to diversify this workforce. FAA could also leverage BLS data on the race and ethnicity of certificated and non-certificated aircraft mechanics and service technicians more broadly as it begins to develop and implement any activities related to expanding and diversifying the talent pool for recruiting workers into aviation maintenance careers. Pathway data. FAA also maintains mechanic pathway data, but these data do not provide a complete picture of certificated individuals’ education, training, and work experience due to certain data limitations. For example, FAA does not require AMT Schools to report program completion data. As a result, it does not have information such as how many students who enter FAA-approved AMT Schools complete the program. Moreover, FAA does not analyze nationwide trends for AMT Schools using existing data on these schools (such as enrollment or mechanic test pass-rate data) or aggregate information across AMT Schools to better understand the AMT School pathway as a whole. In addition, pathway data collected by FAA do not clearly differentiate between civil and military work experience. Specifically, FAA officials said practical, or civil, work experience pathway data may include information on individuals with both prior military and civil experience. Moreover, according to an FAA official, FAA’s military experience pathway data may include individuals who completed DOD’s FAA- approved A&P training program as well as individuals who met FAA’s on-the-job training requirements through relevant military experience. Combined pathway data may limit FAA’s and DOD’s understanding of DOD’s contributions to this workforce, including the number of individuals who completed DOD’s FAA-approved A&P training program and subsequently obtained mechanic certification from FAA. Supply and demand data. Other federal agencies, such as BLS and DOD, maintain data that relate to this workforce more broadly that could be useful to FAA. For example, FAA could leverage BLS data on the projected employment of certificated and non-certificated aircraft mechanics and service technicians in conjunction with its data on newly certificated workers each year to better understand worker supply and demand. DOD also maintains information on separating service members with aviation maintenance backgrounds, who may be attractive to the commercial aviation industry. For example, according to a DOD official, in fiscal year 2018 over 22,000 service members with aviation maintenance backgrounds separated from the Air Force and Navy. Additional data analysis and coordination could potentially yield useful information on worker supply and demand and areas for promoting the development of this workforce. Without routinely analyzing its existing data on certificated workers, collecting additional data, or leveraging existing workforce data maintained by other federal agencies, FAA will not have certain information it needs to measure progress and strategically target its resources toward its objective of promoting the development of a robust aviation workforce. A robust aviation workforce, including certificated mechanics and repairmen, is necessary for maintaining a safe aviation system. FAA’s recently developed Aviation Workforce Steering Committee presents the agency with an opportunity to engage other federal agencies in discussions on how to leverage data to expand and diversify this workforce. Even as FAA’s strategic plan states the agency’s focus on promoting the development of a skilled aviation maintenance workforce to integrate new technologies, the agency has acknowledged that the current curriculum requirements for AMT Schools and mechanic testing standards are outdated. Efforts to revise the curriculum requirements for AMT Schools are ongoing through the rulemaking process, and FAA is also currently updating the testing standards for mechanics. The curriculum requirements for AMT Schools have remained largely unchanged for several decades despite numerous attempts to update them as aviation technology has evolved. The minimum requirements are established in regulation and list the subjects that AMT Schools must include in their training curriculum for individuals to be eligible to take FAA’s mechanic tests. FAA officials, employers, and AMT School officials we interviewed said the current curriculum requirements do not emphasize commonly used modern aircraft technologies, such as avionics and composite materials. Because the curriculum requirements are established in federal regulation, FAA has attempted several times to revise them through the rulemaking process. Table 1 provides selected changes or actions relating to these requirements. FAA officials noted several challenges to updating the AMT School curriculum requirements, including competing demands at the department level, the extent of comments FAA has received from stakeholders in response to proposed changes, and the amount of time required to coordinate with internal stakeholders during the review process. We previously reported on factors that affect the amount of time needed to issue a rule for selected agencies, which included similar challenges such as the complexity of an issue, agency management priorities, and the amount of review required at different phases of the rulemaking process. In October 2015, FAA published a notice of proposed rulemaking (NPRM) with the stated goal of updating the existing AMT School curriculum and providing an efficient means of changing specific course items by including them in each school’s operations specifications (see fig. 6). This would eliminate the need to go through the federal rulemaking process to update the curriculum. As part of its ongoing efforts to revise the curriculum requirements for AMT Schools through the rulemaking process, FAA issued a supplemental NPRM in the April 2019 Federal Register that expanded the scope of the NPRM it issued in October 2015 (see fig. 6). Comments on the supplemental NPRM were due in June 2019. As of October 2019, FAA officials said they were in the process of reviewing the comments. In a separate effort outside of the rulemaking process, FAA is currently updating the testing standards for mechanics. The standards were last revised in 2015. FAA has acknowledged that current mechanic testing standards are also outdated. As a result, aviation stakeholders have stated that the mechanic tests include outdated or irrelevant questions. For example, the practical test may include projects on wood airframes and fabric coverings, which are not common to modern commercial aircraft. FAA has stated that the revised testing standards will provide a comprehensive framework for the mechanic tests and serve as a guide for reviewing and revising the oral and written test questions and the practical projects. FAA officials said two offices within the agency are responsible for updating AMT School training curriculum requirements and mechanic testing standards and that these offices have been coordinating efforts to align the two. FAA’s efforts to modernize the curriculum requirements for AMT Schools and its efforts to update the mechanic testing standards started on slightly different paths, in part due to differences in when the working groups were formed and recommendations to address these issues were made (see fig. 7). As of October 2019, FAA had not issued a final rule for modernizing AMT School curriculum requirements as required by the FAA Reauthorization Act of 2018, and it was still in the process of updating testing standards. FAA officials have indicated that they have informed the appropriate committees in Congress that the proposed schedule for issuance of a final rule is in October 2020 and said that the revised mechanic testing standards would likely be finalized after the publication of the final rule amending the curriculum requirements for AMT Schools. An FAA official noted that any delay in finalizing the rule would likely result in a corresponding delay to finalizing the testing standards. Delaying the release of the updated mechanic testing standards could result in the prolonged use of outdated or irrelevant questions on the mechanic tests. FAA officials said that once finalized and implemented, the updated curriculum requirements for AMT Schools and the mechanic testing standards for individuals should be mostly aligned. A sufficient supply of aviation maintenance workers is critical to maintaining a safe and robust aviation system and meeting the growing demand for air travel. Current training and skills requirements for these workers are also important because of changing flight technology. Both the federal government and other industries benefit from having a professional, trained, and qualified workforce, and addressing aviation workforce needs is a shared responsibility among these different stakeholders. As the federal agency responsible for certificating aircraft mechanics and repairmen, FAA maintains certain demographic information on these individuals that could shed light on the characteristics and employment of these personnel. However, without strategically using or analyzing the data it has along with data other stakeholders collect, FAA will not have certain information it needs to target its resources or measure and improve progress toward its aviation workforce goals. It may also miss the opportunity to provide other stakeholders with valuable information for supporting these workers. Other agencies and stakeholders may also assist FAA in understanding and promoting the development of the aviation maintenance workforce. FAA’s recently developed Aviation Workforce Steering Committee presents the agency with an opportunity to engage other federal agencies to explore potential data sources and their usefulness and discuss ways to expand, diversify, and strengthen career pathways for the aviation maintenance workforce. The Administrator of FAA should direct the Aviation Workforce Steering Committee, as part of its ongoing efforts, to take steps to use existing FAA data and coordinate with other federal agencies to identify and gather the information it needs to measure progress and target resources toward its goal of promoting a robust, qualified, and diverse aviation maintenance workforce. For example, FAA could task a committee working group with developing and implementing ways to improve data sharing among federal agencies to inform decision-making on how to strengthen career pathways and better understand the supply and demand of certificated workers. (Recommendation 1) We provided a draft of this report to DOT, DOL, Education, DOD, and VA for review and comment. DOT provided written comments, which are reprinted in appendix II. DOT concurred with our recommendation. Specifically, DOT agreed that using existing data could potentially contribute to its efforts to develop the aviation maintenance workforce. DOT said it will ask the Aviation Workforce Steering Committee to consider using existing FAA data and to coordinate with other federal agencies regarding other potential data sources to support the FAA’s aviation maintenance workforce goals. DOL provided technical comments, which we incorporated in the report as appropriate. We are sending copies of this report to the appropriate congressional committees, the Secretary of the Department of Transportation, the Secretary of the Department of Labor, the Secretary of the Department of Education, the Secretary of the Department of Defense, the Secretary of the Department of Veterans Affairs, and other interested parties. In addition, the report is available at no charge on the GAO website at https://www.gao.gov. If you or your staff have any questions about this report, please contact me at (202) 512-7215 or gurkinc@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made key contributions to this report are listed in appendix III. While no single metric can be used to determine whether a labor shortage exists, certain indicators in conjunction with views of stakeholders can provide insight on this issue. We previously found, based on our review of economic research, that an occupation experiencing a labor shortage would exhibit the following: (1) a low unemployment rate signaling limited availability of workers in that profession, (2) increases in wages offered to draw people into that profession, and (3) increases in employment due to increases in demand for that occupation. Table 2 shows these specific indicators from 2013 through 2018 for the aircraft mechanics and service technicians occupation, measured using Bureau of Labor Statistics (BLS) Current Population Survey data. According to our analysis of BLS data from 2013 through 2018, unemployment rate and change in median wage earnings for the aircraft mechanics and service technicians occupation, which includes both Federal Aviation Administration-certificated and non-certificated workers, were consistent with the existence of hiring difficulties, while the percent change in employment was not. Data on two of the three indicators (unemployment rate and wage earnings) were consistent with difficulties in hiring aircraft mechanics and service technicians. However, because these data combine information for certificated and non-certificated workers, it is difficult to know the extent to which any hiring difficulties represent demand for certificated workers, specifically. In addition, the indicators should be viewed with appropriate caveats. For example, while median wages increased for aircraft mechanics and service technicians in 2018 compared to 2013, they did not increase in every year—and they exhibited decreases of as much as 6.7 percent. The direction of change of the employment indicator was not consistent with hiring difficulties for this occupation. As shown in table 2, from 2013 through 2018, employment for aircraft mechanics and service technicians does not appear to have changed, while employment for all other occupations increased. However, employment for this occupation did not remain constant in every year over that time period and exhibited increases of as much as 12.5 percent and decreases of as much as 21.9 percent. Chelsa Kenney Gurkin at (202) 512-7215 or Gurkinc@gao.gov. In addition to the contact named above, Betty Ward-Zukerman (Assistant Director), Meredith Moore (Analyst-in-Charge), Ellie Klein, and Chris Woika made key contributions to this report. Additional assistance was provided by James Bennett, Lilia Chaidez, Holly Dye, Serena Lo, Sheila R. McCoy, John Mingus, Michael Naretta, James Rebbe, Almeta Spencer, and Andrew Von Ah.