A new report from the Government Accountability Office (GAO) has exposed a personnel crisis within the United States Air Force (USAF). Although the USAF has some of the best aircraft and pilots in the world, it is struggling to train and retain enough enlisted personnel to maintain its fleets. Although in 2017, the USAF had a surplus of junior maintainers–known as Level 3 maintainers–it is still desperately short on more experienced hands. Those qualified at Levels 5 and 7 are necessary to train junior airmen and ensure aircraft are combat-mission ready.

Aircraft maintainers make up about 25% of the entire enlisted force, according to a report from Flight Global. Aircraft maintenance careers make up the largest group of enlisted Air Force Specialty Codes (AFSCs)–the equivalent of a Military Occupation Specialty (MOS) in the Army and Marine Corps. According to the GAO, the USAF has more than 100,000 airmen currently working in this job group spread among the active duty force, the reserves, and the Air National Guard. Still, in 2017, at least 745 additional Level 5 and 7 maintainer slots went unfilled. The service’s goal is to keep at least 80% of aircraft in the most necessary 204 squadrons on flight status, according to Flight Global.

“Over the past eight fiscal years, the Air Force has increasingly lost experienced aircraft maintainers, and it does not have goals and a strategy to help retain maintainers,” wrote the GAO in its report. “While overall maintainer loss rates have remained generally stable, loss rates of 5 levels increased from 9% in fiscal year 2010 to 12% in fiscal years 2016 and 2017.”

The issue of a lack of personnel compounds on itself. As commanders push hard to keep aircraft flight-worthy, maintainers are forced to work longer hours, even though the maintenance shops are understaffed. This increased stress often drives enlisted personnel away from reenlistment, which in turn, means the shops are now even more short-staffed. Although the USAF has increased its use of retention and recruitment incentives like bonuses, it cannot “buy” more experienced personnel.

Still, even with the use of “tactical” recruitment and retention measures, the USAF lacks a cohesive strategy when it comes to keeping experienced maintainers. It also currently has no metric retention goal, so commanders have no point of reference to measure the success of bonus programs. The GAO recommended the USAF develop both a strategy and a goal-set immediately.

The report concludes: “The Secretary of the Air Force should develop annual retention goals for aircraft maintainers by skill level—for both loss and reenlistment rates—in alignment with authorized levels.”