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What are the key factors driving F-35 maintenance costs?
Executive summary
Multiple government reviews and journalism identify several recurring drivers of high F‑35 maintenance and sustainment costs: complex stealth materials and advanced electronics that require specialised repairs and diagnostics, parts and repair supply‑chain delays that push buyers to purchase costly replacements, and rising lifecycle estimates as the fleet’s service life is extended—GAO cites sustainment estimates rising from $1.1 trillion to $1.58 trillion between 2018 and 2023 [1]. Industry and program office spokespeople say some unit‑level metrics (cost per tail, cost per flight hour) have improved and attribute part of the overall increase to a longer calculated service life [2].
1. Stealth coatings, advanced systems and “built‑in” complexity
A central technical cause of high sustainment costs is the F‑35’s fifth‑generation design: low‑observable (stealth) materials and very advanced sensors, avionics and thermal/power management systems produce different and more costly maintenance needs than fourth‑generation jets. The Congressional Budget Office notes that stealthy aircraft “have different maintenance requirements because of the materials used on the skin of the aircraft” [3]. The GAO and media reporting also point to engine and cooling‑system stresses that reduce component life and add projected maintenance bills [4].
2. Parts availability and repair logistics raise bills
GAO investigators and defense press reporting highlight that long repair turnaround times and limited government repair capacity have led the program office to buy new parts instead of waiting for repairs—an expedient that increases sustainment spending. The GAO found that the Joint Program Office “often buys new parts at a higher cost” rather than wait months for repaired components, driving up sustainment costs [5]. GAO recommends reassessing the balance of contractor vs. government sustainment roles to lower costs [5].
3. Scale, longevity and accounting choices expand headline totals
How costs are calculated matters. The F‑35 program office told reporters that part of the reported increase reflects an 11‑year extension of the fleet’s assumed end‑date (from 2077 to 2088), which inflates lifecycle sustainment totals because the program must report comprehensive costs over a longer period [2]. GAO, however, emphasizes that even with that extension, the sustainment estimate rose 44% (from $1.1 trillion to $1.58 trillion) between 2018 and 2023 [1].
4. Usage rates and availability interact with per‑unit costs
Lower planned flight hours and reduced fleet availability change per‑aircraft and per‑flight‑hour economics. GAO reports that services plan to fly F‑35s less than originally estimated and that fleetwide availability has been below program targets—factors that can raise average annual sustainment costs or obscure gains in unit efficiencies [1]. The CBO also reports fleetwide availability in the 50–60% range versus a target of 65% [3].
5. Differing claims: program improvements vs. watchdog concerns
The program office and industry point to measurable improvements in some unit metrics: the F‑35 Joint Program Office claims a 34% improvement in cost per tail per year and a 61% improvement in cost per flying hour from 2014–22 [2]. Lockheed Martin says it reduced its portion of sustainment costs dramatically and controls “about 40 percent” of factors affecting maintenance costs [6]. GAO and independent analysts counter that programwide sustainment estimates and structural sustainment practices (contractor dominance, spare repair networks) still leave total costs high and that buying parts to avoid long repairs is a costly workaround [1] [5].
6. Where targeted reforms could reduce costs — and where reporting omits detail
GAO recommends reconsidering whether the government should take on more sustainment responsibilities, improve technical data access, and build faster repair networks; DefenseNews and GAO reporting say doing so could save billions [5]. Program statements stress digital transformations, prognostics, and supply‑chain improvements as levers [7] [6]. Available sources do not mention specific dollar savings validated post‑implementation beyond Lockheed Martin’s internal claims and the program office’s percentage improvements [6] [2].
7. Bottom line and takeaways for readers
Independent watchdogs (GAO, CBO) present a consistent set of structural drivers—complex stealth systems, slow repair logistics, extended lifecycle accounting, and reduced flight rates—behind rising program sustainment totals [1] [3] [5]. The program office and industry counter with metrics showing per‑unit improvements and attribute part of the increase to longer service life assumptions [2] [6]. The disagreement is therefore less about single technical causes and more about which effects (longer service life versus repair practices and supply chains) explain the larger dollar totals; readers should weigh GAO’s program‑wide totals and critiques [1] [5] alongside program office and contractor statements about localized efficiency gains [2] [6].