The Pentagon forged a deal with defense contractor Lockheed Martin for F-35 fighter jets Monday amidst allegations it has not fulfilled maintenance needs for the existing fleet.

Lockheed Martin reportedly reached a handshake agreement to deliver 375 F-35 Joint Strike Fighters to the Pentagon Monday for an estimated $30 billion, Reuters reported. The deal comes after the Government Accountability Office (GAO) released a report Tuesday finding that the Department of Defense (DOD) has not developed a strategy to repair engines for the costly fighter jet.

“Challenges sustaining the F-35 engine may pose its greatest sustainment risk over the next 10 years,” the GAO said. “Inadequate maintenance depot capacity leading to a shortage of operating power modules have grounded F-35s more often and for longer time periods than expected.”

Up to 6% of the U.S. military’s F-35 warplanes remain grounded for an indefinite period of time, according to the GAO. That number for other aircraft is only 1%.

Supply chain issues have also led to a shortage of spare engines, according to the GAO. Pratt & Whitney, the company that produces the F-35 engine, has “continued to have problems with the quality of engines and the timeliness of deliveries.”

Contracts for F-35 lots 15 through 17 will be awarded in late summer or fall, a Lockheed spokesperson told Defense News, when more information about which countries will ultimately purchase the fighter becomes public. The final price and quantity have not yet been determined, and are dependent on Congress’s 2023 defense budget, according to Defense News.

Lockheed told Defense News it outpaced inflation and COVID-19 impacts in reducing the final cost for each F-35.

The most F-35 contract in 2019 reached the “lowest aircraft price during the history of the Program,” according to a press release. Costs ranged from $77.9 to $108 million per aircraft.

Lockheed posted quarterly earnings Tuesday well below expectations, noting that profit plummeted to $309 million in 2022 compared to $1.8 billion the same time in 2021, Defense News reported. Lockheed downgraded its forecast for earnings per share 19%.

The Pentagon’s F-35 fleet has over 400 aircraft, according to the GAO. It also plans to procure 2000 more by the mid-2040’s, requiring $1.3 trillion spent just on maintenance throughout the lifespan of the F-35s.

The Senate’s version of the 2023 National Defense Authorization Act authorizes $27,000 in additional funding for engine repair facility test modules for the Air Force and $13,500 for the Army, according to the bill report with an overall program increase.

The F-35 program, shared with seven partner nations and seven additional buyers, is “DOD’s most ambitious and costly weapon system in history,” the GAO said. Despite billions in Congressional funding allocations, cost and performance issues have plagued the program.

The Czech Republic announced its interest in the F-35. As the #F35 continues to grow as the foundation of NATO and European alliance’s next generation of air power, it will ensure national security for decades to come.

— F-35 Lightning II (@thef35) July 20, 2022

Lockheed is “changing gears” to adapt to increased U.S. defense spending, Taiclet said Tuesday, according to Defense News. Doing so will take years, he added.

The DOD, the Air Force, Pratt & Whitney and Lockheed Martin did not immediately respond to the Daily Caller News Foundation’s request for comment.