F-35A Caught In Acquisition Dogfight Within U.S. Air Force

U.S. Air Force F-35A aircraft
F-35A deployments to the Middle East have exposed a durability issue for the engines, which has compounded a bottleneck at the repair depot.
Credit: U.S. Air Force

The Lockheed Martin F-35A is in trouble again. The U.S. Air Force is openly considering more affordable alternatives, including a clean-sheet design for a new fourth-generation fighter. A repair bottleneck, meanwhile, is choking the supply of engines, which threatens the operational fleet with groundings and restricted operations. And promised cost savings could still fall short of an ambitious target.

Hundreds of orders by the Air Force for F-35As far into the future could be at risk, starting with the size of the President Joe Biden’s first budget request to Congress for fiscal 2022.

  • Two Pentagon reviews reassessing TacAir portfolio
  • The initial focus is on the Air Force’s fiscal 2022 budget plan
  • A clean-sheet fighter is among the near-term options

The F-35A is one of three aircraft programs singled out for special review by new Deputy Defense Secretary Kathleen Hicks ahead of the fiscal 2022 budget submission this spring. For three consecutive years, the Air Force has sent annual requests for 48 F-35As to Congress along with an “unfunded priority” for 8-14 more, which lawmakers have approved (see table). The Hicks-directed review now casts the size of the baseline request into question, as well as any Defense Department tacit support for supplementary orders chipped in by lawmakers.

But the last-minute budget drill for fiscal 2022 is only a warm-up. Two separate studies are underway to reset the composition of the Defense Department’s tactical aircraft fleet plan for the first time in over a decade. The Pentagon’s Cost Analysis and Program Evaluation office will lead one study, and the Joint Staff another. Both studies will inform decisions for the fiscal 2023 budget request but could profoundly reshape U.S. tactical air procurement for several years to come.


“Development of an updated schedule that addresses all the previous causes of schedule overruns has got to be informed by a detailed understanding of the path ahead and associated timelines,” Pentagon spokesman John Kirby told reporters on March 9.

“We are continuing an analysis here, and we’ll deliver the proposed acquisition production baseline revision when it’s complete,” he said.

The uncertainty at home comes at a critical time for the F-35A abroad. With a limited pool of customers trusted and well-funded enough to acquire the U.S. defense industry’s premier export product, the F-35A now must overcome the atmosphere created by a rising chorus of domestic criticism to win competitive contracts for about 200 aircraft orders this year by Canada, Finland and Switzerland combined. The UK, meanwhile, is poised to reveal the results of the delayed Integrated Review of Security, Defence, Development and Foreign Policy, with the F-35B program vulnerable to deep cuts.

As foreign governments decide how much to invest in F-35s, they are hearing a clamor of confused messages about the aircraft’s value from U.S. Air Force leadership. With Congress’ approval, the Pentagon’s request in 2019 to buy the first eight of 144 Boeing F-15EXs broke the F-35A’s decade-long monopoly on the Air Force’s fighter procurement. But U.S. defense officials were careful to frame that decision as a one-off, expedient solution to an airframe longevity crisis that had erupted within the Boeing F-15C/D fleet.

U.S. Air Force F-35A aircraft
A looming replacement decision for Block 25/30/32 F-16s is considering a wide range of alternatives to the F-35A, due to affordability concerns. Credit: U.S. Air Force

The ongoing fleet reviews offer no such cover. Within the next few years, the Air Force plans to start replacing a fleet of so-called “pre-block” Lockheed F-16s, which includes 211 Block 30s, 37 Block 32s and 20 Block 25s, according to Aviation Week’s Military Fleet Discovery Database. Since 2001, the F-35A has stood officially as the service’s only replacement option for the pre-block F-16 fleet, but that is no longer the case.

As the internal Pentagon reviews progress, a wide range of alternatives to the F-35A are in consideration for replacing pre-block F-16s, including unmanned aircraft systems to perform a subset of the adversary air mission, new-build F-16s and a clean-sheet fighter that U.S. Air Force Chief of Staff Gen. Charles Q. Brown, Jr., has described loosely as either a “fourth-generation-plus” or “fifth-generation-minus platform.”

As the Air Force considers options, a major driver is a single metric: operating cost. In 2018, then-Chief of Staff Gen. David Goldfein warned that the F-35A’s operating costs made the service’s plans to ramp up production impossible. Lockheed and the Joint Program Office responded by committing to lowering the F-35A’s cost per flight hour to $25,000 by 2025, a significant reduction from about $35,000 last year.

The program office has reported further progress, including signing annual sustainment contracts in fiscal 2020, which lowered the cost per flight hour by $2,000. Another initiative is replacing the much-criticized Autonomic Logistics Information System (ALIS) with the Operational Data Integrated Network (ODIN). Moving the administration of maintenance tasks to a cloud-based network can, in theory, help the Air Force save significantly on personnel costs. An army of administrators distributed to each unit could be consolidated at ODIN support hubs, but only if Air Force leaders accept such streamlined organizational changes.

Some service officials remain skeptical that the operating costs of the F-35A will become competitive with the F-16 within four years.

“In terms of [my] confidence level of getting to $25,000 [cost per flight hour] by 2025, I’m not brimming with confidence,” Air Combat Command Chief Gen. Mark Kelly said at the Air Warfare Symposium in late February, adding: “I haven’t lost confidence.”

The F-35A’s operating cost problem is now impossible to ignore. With the first 12 lots of low-rate initial production delivered, the F-35A now counts as the second-most numerous fighter fleet in the Air Force inventory behind only the F-16C/D, with an hourly operating cost more than 50% higher.

The service faces another problem with the availability of the F-35A. Deployments to the Middle East resulted in heavy usage in the region’s sand-flecked atmosphere, exposing a durability problem with the original coating applied to the high-pressure turbine blades inside the Pratt & Whitney F55 engine.

“They’ve been deployed to different locations, and that extra time on the engines is causing them to fail a bit sooner,” Brown told journalists on Feb. 17.

Pratt & Whitney, however, says the overall number of unscheduled engine removals is still below the manufacturer’s expectations. A new coating for the turbine blades also is being developed to fix the durability problem, says Matthew Bromberg, president of Pratt & Whitney Military Engines.

The fleet availability problem is caused by a bottleneck at the F135 repair depot, Bromberg says. The depot has been overwhelmed by a surge of workload. Scheduled engine removals started on F135 engines for the first time this year. Unscheduled engine removals, including because of the coating problem, also are flowing into the depot. Routine, fleet-wide configuration updates have to be processed through the depot as well. The F135 employs a two-level maintenance concept, meaning interior repairs to the power modules must be handled by the depot rather than at the operational unit. Two-level maintenance is supposed to be more efficient, but only if the depot is ready to handle the workload.

U.S. Air Force F135 repair depot
The U.S. Air Force opened a repair depot for the F135 in 2014, but output at the site has fallen behind demand for heavy engine maintenance this year. Credit: U.S. Air Force

“All those things combined into a number of parallel engine removals,” Bromberg says. “The coating issue was actually just a small percentage of it.”

In response, Pratt & Whitney has doubled the amount of support equipment at the F135 depot at Tinker AFB, Oklahoma. The company also has halved the time required to publish technical data documents that are required to complete repairs on the shop floor, Bromberg says. Those changes should expedite the flow of engines through the depot over time, but Bromberg was unable to provide a timeline for resolving the bottleneck fully.

In the meantime, the Air Force is planning to limit normal operations by the F-35A in order to slow the pace of engines flowing into scheduled maintenance at the depot.

“I want to moderate how much we’re using those aircraft,” Brown said. “It’s like your Ferrari. You don’t drive your Ferrari to work every day. You only drive it on Sundays. This is all high-end. We want to make sure we don’t use it all for a low-end fight when we want to save it for the high-end fight.”

Low-end operations include air strikes on insurgents and countries that lack modern air defenses. The “high-end fight” refers to a war against China or Russia, which have surface and airborne weapons that can challenge the F-35. For the latter conflict, the F-35A remains the “cornerstone” of the Air Force’s tactical air power, Brown said.

Indeed, service planners continue to broaden the F-35A’s role in a future conflict. In addition to replacing the F-16’s ground-strike role with a stealthy platform, the F-35A also could be used as a forward-based, target-cueing system for missile defenses. Another mission could be as part of the Advanced Battle Management System, with the F-35 playing a role as a critical node in a distributed and automated command-and-control network. Even in low-end conflicts, supporters contend the F-35A still may be needed, as Russia has deployed S-400 air defense batteries to Syria and Libya, posing a tacit threat to nonstealthy aircraft.

An additonal argument in favor of the F-35A is a dire lack of immediately available alternatives. The Air Force has estimated that it needs to buy 72 fighters a year simply to keep pace with older aircraft being retired. Boeing delivered the first F-15EX to the service on March 10, but the fiscal 2021 budget plans support a production ramp-up to a steady state of 19 jets a year in 2024. An order for new F-16s, which was proposed by then-Air Force acquisition chief Will Roper in January, would not deliver any new F-16s until at least 2025, and only then if the service accepted the current international standard with no upgrades for range, electronic warfare or communications.

A clean-sheet design poses a new set of intriguing possibilities, but the timeline raises questions. The F-35 and Lockheed Martin F-22 spent 15 years in development before entering service. But the Air Force believes a new set of digital engineering tools can usher fresh, state-of-the-art aircraft into service in 5-7-year cycles. For proof, the Air Force points to the Boeing T-7A advanced jet trainer, which is scheduled to enter service six years after contract award in 2018. Air Force officials also cite the example of the secret flight demonstrator for the Next-Generation Air Dominance (NGAD) program, although they decline to provide any further details except that an aircraft is now flying.

A new jet, however, would only compound the Air Force’s complicated fighter inventory, which already includes the F-22, F-35A, F-15EX, F-15E, F-15C/D, F-16C/D and Fairchild Republic A-10. A small number of Lockheed F-117s also remain in flyable storage. And a long-range member of the NGAD family of systems also is in the early stages of development. Still, the possibility of adding a new, low-end jet with a design that originated in this century clearly intrigues Brown.

“If we’re going to do software-defined [systems] and we have the capability to do something even more capable for cheaper and faster, why not just buy something off the shelf?” Brown asked. “Let’s actually take a look [whether there is] something else out there that we can build.”

Some powerful lawmakers also are ready to move on from the F-35A as the service’s primary fighter for the future. “I want to stop throwing money down that particular rathole,” House Armed Services Committee Chairman Adam Smith (D-Wash.), said March 5 during a virtual Brookings Institution event.

“What I’m trying to figure out is how we can get a mix of fighter attack aircraft that’s the most cost-effective,” Smith added. “A big part of that is finding something that doesn’t make us rely on the F-35 for the next 35 years.”

Steve Trimble

Steve covers military aviation, missiles and space for the Aviation Week Network, based in Washington DC.


The latest F-16 versions are definitely much better as replacements for retiring old F-16's.

Remove the high end fighters from low end missions, and stand up via MROU appropriate aircraft from the boneyards or current inventory for low end missions.

The affordable Basler BT-67 can do a lot of the low end missions.
One would have thought, after 20 years of the "Global War on Terror", that decision makers would have finally realized that "low-end" wars do nothing except sap America's strength. Since the US has already spent over $6 trillion on GWoT, the Chinese will be delighted if America continues this folly.

Every fourth generation fighter purchased will mean fewer resources for deterring a near peer conflict. Which increases the probability that this undesired outcome becomes a reality.
You wrote:
"[...] exposing a durability problem with the original coating applied to the high-pressure turbine blades inside the Pratt & Whitney F55 engine."

That should probably be "F135 engine".

You also write:

"[...] the Air Force has sent annual requests for 48 F-35As to Congress along with an “unfunded priority” for 8-14 more, which lawmakers have approved (see table)."

Which table are you referring to? I can't find any table in this article!