Stealth and sophisticated sensor and data fusion make the F-35 the most advanced fighter aircraft in the world, and operators praised its performance on combat deployments for operations in Syria and Iraq. But high operational costs and shortages of parts and trained depot technicians continue to plague the program. Airman 1st Class Duncan Bevan
Photo Caption & Credits

Make-or-Break Time for the F-35

April 23, 2021

The Air Force’s most important program faces increased scrutiny as high costs, low availability, and other problems continue.

Despite solid combat performance, the F-35’s high maintenance costs and ongoing parts supply problems continue to be a drag on the fifth-generation fighter aircraft, giving critics ammunition as Congress readies to receive the Biden administration’s first budget.  

     Lockheed Martin is delivering F-35s at a rate of roughly 11 a month—about five of which go to the Air Force—and largely on schedule. Operators seem satisfied with its combat performance. But parts problems, engine support issues that will take years to correct, and an evolving performance-based logistics concept suggest a program overhaul may be coming, once the Biden Administration installs its new defense acquisition team.  

In early March, House Armed Services Committee Chairman (HASC) Adam Smith (D-Wash.) wondered aloud at a Brookings Institution event if there was any way to “cut our losses” on the F-35. He called sustainment costs “brutal” and characterized the program as a “rathole.” Mid-month, at a hearing of the HASC’s Readiness subcommittee, Chairman Rep. John Garamendi complained “the entire F-35 system is of enormous concern.” 

“We buy more planes,” Garamendi said, but “we’re not able to maintain the older ones. So the more we buy, the worse overall performance has been. That is going to stop.”

He said Congress would direct the Air Force to provide an “integrated maintenance plan” in the next few months showing that it can smartly manage both new and classified systems, including the F-35. The service must prove that the maintenance needs of new systems are understood and will be properly funded, Garamendi stated. If it can’t, it needs to identify which systems it can do without.

The more  we buy, the worse overall performance has been. That is going to stop

Rep. John Garamendi, Chairman HASC readiness subcommitee

Kelly’s Get-Well Tour

Gen. Mark D. Kelly, head of Air Combat Command, toured F-35 manufacturing and support facilities in March, hoping to see evidence that F-35 availability is improving and that its $36,000 cost per flying hour is  coming down. But Kelly said he’s unconvinced.

“The takeaway is that the Air Force is committed to the F-35 and its capabilities to meet our national security requirements,” Kelly said in an email response to questions. Echoing Chief of Staff Gen Charles Q. Brown Jr., he called the F-35 the “cornerstone” of the combat air forces.

“But like any cornerstone, it must be strong enough to hold up the rest of the Air Force’s fighter house,” Kelly added. 

The question is whether the F-35 program can reach its stated goal of reducing its cost per flying hour by 2025 to $25,000, based on fiscal 2012 dollars. Adjusted for inflation, that’s the equivalent of $28,867 in 2021 and, assuming 3 percent inflation, $32,233 in 2025. 

“Rational parties can disagree without being disagreeable,” Kelly said. “Lockheed Martin is still confident that $25K by 2025 is achievable, and I’m still not brimming with confidence.” Assuming a 3 percent inflation rate on current costs, maintenance would have to come down more than 35 percent to meet that target. 

The stakes couldn’t be higher: The Air Force needs “a capable, available, and affordable F-35 as part of a deliberate fighter force design to outpace any competitors,” he said.

The F-35 has performed well in deployments and proved its mettle, Kelly added.  

“We operated the F-35 for 18 consecutive months in/around the Russian integrated air defense network in Syria, and the Marines and [U.K.] Royal Navy are operating the F-35B in global operations,” he said. “To that end, I’d say it’s been ‘shaken out,’ and it’s performed very well in the contested environment.” 

During three six-month deployments from Hill AFB, Utah, from April 2019 to October 2020, 42 F-35s flew more than 1,300 sorties—averaging five hours each—dropping 350 weapons and firing 3,700 cannon rounds, all while maintaining an average mission capable rate of 70 percent. The jets were supported by 1,100 Airmen.

The Air Force wants to step it up, though, Kelly said, aiming to “progress from [performing] ‘very well in contested environments’ to ‘outstanding in highly contested environments,’” and that requires the Technical Refresh 3 upgrade, which “unlocks” the jet’s Block 4 improvements.

Tech Refresh 3—or TR3 for short—comprises a new core processor, a radar upgrade and a new cockpit display, as well as numerous software improvements, including enhanced electronic warfare capabilities. Block 4 is the Air Force’s preferred model.

Brown suggested at the Air Force Association’s Aerospace Warfare Symposium in February that accelerating F-35 purchases is one way to more rapidly modernize its fighter force, but Kelly said that’s unlikely. “I’ll defer to the [Headquarters, Air Force] for programmatics, but I don’t see the current budget environment supporting robust ‘accelerations’ of many programs,” he said. The Air Force’s program of record remains unchanged at 1,763 F-35As. But at the current rate of 60 per year, it will be the early 2040s before that objective is attained.  

We’ll Wait for the Next One

Getting to the right version has been one factor slowing down the program. A Joint Program Office (JPO) spokeswoman said in March that some services have “had to rephase” their F-35 buying plans or “decided that they’d rather buy later and hold on for the Block 4 capability.” 

The next three F-35 production lots, now in negotiation, will collectively include 100 fewer aircraft than the prior three lots, according to Gregory M. Ulmer, Lockheed’s long-time F-35 program manager who was recently promoted to executive vice president of aeronautics.     

Kelly said the Air Force is keenly aware that it cannot afford the luxury of taking decades to develop new aircraft, and acknowledged the F-35 is taking too long. In the long war against violent extremism, the enemies were unable to “punish” USAF and its sister services for going to war with “an aging fleet, or for recapitalization and modernization efforts that either cost more than planned, delivered late, or delivered less than the full capability.” But in a fight against peer adversaries, that will not be the case. 

Time now is critical. Block 4 F-35s “can compete and win in a peer fight,” he said. “So we need TR3 to show up on time.”

A spokeswoman for the F-35 Joint Program Office said the TR3 upgrade “will deliver to Lot 15 in 2023, as required.” 

Kelly said the Air Force is “still on track to have over 20 combat-ready F-35 squadrons in our inventory by 2030,” the capacity mandated by the National Defense Strategy. If USAF holds to 24 jet squadrons, 20 squadrons would account for only 480 aircraft, suggesting that the Air Force could reach that number by 2027. If the Air Force continued to acquire planes at the current 60-per-year pace, it would have another eight squadrons around 2030. What happens beyond that is unclear, but it could leave room for an early end to the program—if another option is available. 

The Air Force is indeed looking at other options. Kelly took pains at the Aerospace Warfare Symposium to argue in favor of the Next-Generation Air Dominance (NGAD) program and developing that sixth-generation capability before China does.

“I don’t know … if our nation will have the courage and the focus to field this capability before someone like the Chinese fields it and uses it against us,” he said in a video press conference. The U.S. way of war assumes control of the air, he said, and “it’s less designed to operate without it.”

A new joint-service combat aircraft study now underway  will assess the needs of the combat air force and what mix of aircraft it will need in the future. That mix will likely include NGAD, F-35, the F-15EX, and unmanned aircraft, which could be armed or provide electronic warfare escort. Also in the offing could be a lower-cost, manned aircraft for use in low-threat environments, and low-cost “attritable” unmanned aircraft designed for use in dozens of missions or more, but cheap enough that their loss in combat would be acceptable.

The F135 engine pipeline has a cushion of only about 12 percent spare engines and modules, rather than the 25 to 30 percent needed. Airmen wheeled an engine out of a C-17 Globemaster III at Al Dhafra Air Base, United Arab Emirates, to repair an F-35A deployed there in August 2020. Tech. Sgt. Charles Taylor

The Wait for Full Rate 

The Biden administration will have to declare the F-35’s 20-year development program officially over at some point and push into full-rate production. That milestone was postponed for more than 18 months by President [Donald J.] Trump’s Pentagon acquisition and sustainment czar, Ellen Lord, because of difficulties injecting the F-35 into the Joint Simulation Environment, a wargaming system used to model the number and types of weapons systems needed to prevail in various combat scenarios.

The JPO spokeswoman said that it will still be some months before the question can be taken up again, but the program office doesn’t expect “full rate” to lead to a rapid increase in production. The real effect will be to allow the Pentagon to make multiyear purchases and benefit from cost savings as a result. 

Ulmer said that the downward trend in F-35 unit costs will be hard to continue, given reduced quantities in Lots 15 to17, and the more advanced Block 4 configuration. 

The F-35’s sustainment problems tend to boil down to one general issue: early on, the program set optimistic predictions for the availability of parts, depots, and trained maintenance personnel. Shortages of all three have contributed to reducing mission availability for units in garrison, because parts and technicians must be prioritized for deployed units.

The Government Accountability Office (GAO) pegged low mission capable rates to parts shortages in April 2019 and progress continues to be slow. With suppliers producing multiple versions of parts—not just for the A, B and C models, but also for different configurations of each—it has proven difficult to get enough spares. Adding to the complexity, available parts must be shared among the 16 partner countries of the F-35. The GAO faulted the U.S. military services for not having a comprehensive tally of the F-35 parts they owned and where they were. It reported that parts taken along for Marine Corps F-35 deployments sometimes proved incompatible with the planes that deployed.

Faster parts turnaround at the depots could help, but so far gains in aircraft availability have come because jets increasingly come in a common configuration, program officials reported. 

Lockheed F-35 sustainability Vice President Ken Merchant said in February that parts availability is improving. Parts that were at a “fill rate” of 47 percent are now at 97 percent, he said, and things should continue to improve, as this is now just two years into a five-year, get-well plan.

The Engine’s Share 

Problems with the F-35’s Pratt & Whitney F135 engines are also a hindrance. Worst case, the Air Force risks having no working engines for 20 percent of its F-35As by 2025, the F-35 Joint Program Office acknowledged.

The problems are several: The government didn’t order enough F135 engines and engine modules—self-contained sections of an engine—to achieve required availability. And F-35 engine depots are not yet up to speed, both because Pratt has been slow delivering tooling and equipment and because the depots haven’t hired and trained enough people to do the work.

“It’s a vicious circle,” said an Air Force sustainment official. “We couldn’t hire all the folks we need until we have all the tools for them to use.” Pratt is “mostly caught up, but it takes time to hire people … especially under pandemic conditions.” 

The international nature of the F-35 sustainment enterprise is also a challenge. “Technically, we don’t ‘own’ the engines,” the official said. “We get the next one generated. A particular engine can be used by any partner.” 

There are two versions of the engine: one for the USAF A and Navy C models, and another for the F-35B short takeoff/vertical landing model. 

An industry official noted that as the development phase of the F-35 winds down, there should be more stability in the engine configuration, and that will allow suppliers to focus on a smaller pool of variant parts, increasing availability. 

“Basically, the spares they predicted [were] for the mature phase of the program, and we are only getting there now,” an industry official said. “But that means we go into this phase with … a backlog.” 

Industry officials also said that Pratt’s suppliers are not keeping up with the pace the company is asking of them. Officials said the F135 pipeline has a cushion of about 12 percent spare engines and modules, when it really should have 25 to 30 percent. Because Pratt is ahead on delivering engines, a Pentagon official said, talks are underway about producing additional engines and modules.

“You can have fewer engines if your depot is quick in turning them around,” an industry official said. “If the depot’s not up to speed, then you’ll have shortages.”

Another problem with the F135 engine has to do with coatings on fan blades in the high pressure turbine section. When sand in the Middle East known as CMAS—calcium, magnesium, aluminum silicate—is ingested and heated in the HPT, it melts into a glass that damages the blade coatings.  Pratt started applying a new coating a year ago, and so far that seems more durable, allowing the blades to last longer. How much longer is still not known. 

Kelly said he has no plans to restrict F-35s from deploying to the Middle East, however, and that the potential engine shortage has been addressed for the near-term.

The desert environment is “just one factor” in limiting engine life, Kelly said, “along with total engine hours, engine age, foreign object damage, depot throughput capability, etc.” To further mitigate engine shortages, ACC reduced the F-35 demo team’s schedule, freeing up engines to “meet combat training and wartime requirements.” 

Senior Airman Jazmine Brandon enters flight data into the F-35 maintenance system, known as ALIS—for Autonomic Logistics Information System—in 2019. Maligned for its faults and awkward user interface, ALIS will be replaced by the Operational Data Integrated Network, or ODIN, in 2022. Tech. Sgt. Jim Araos

The PBL Deal

Lockheed Martin pitched a performance-based logistics (PBL) proposal to the F-35 partners in 2019, and company officials in February said they expect a sole-source request for proposals this summer. The plan has been “skinnied down,” Merchant reported, but the company is confident it can reach the $25,000/flying hour cost by 2025, even so. The company is proposing a five-year deal with potential follow-on five-year arrangements.

Pentagon officials said the JPO declined the more far-reaching program out of reluctance to give Lockheed even more authority over the sustainment enterprise. 

Savings would result from suppliers making more economic, large-quantity orders, Merchant said. Lockheed is already setting five-year deals with some of its vendors, even though it’s on an annual contract with the government, eliciting “the right behavior” from previously problematic suppliers, Merchant said.

Lockheed and the JPO are midway through switching out the F-35’s beleaguered Autonomic Logistics Information System, or ALIS, in favor of a rebranded and upgraded Operational Data Integrated Network, or ODIN. The old system was based on 20-year-old technology, Lockheed officials said, and needed a massive refresh. The new system is expected to be more secure, produce fewer errors, and easier to use.

ODIN will fully take over from ALIS in late 2022, providing improved insight into F-35 parts usage and service actions, and enabling improved predictive maintenance.

If the various efforts to improve F-35 sustainment bear fruit, the Air Force may actually get close to 1,763 Lightning IIs in its inventory. But at the current pace, and with other projects clamoring for funds and attention, the F-35 could turn out to be just a bridge to the future combat air force, rather than the destination once envisioned.