Over the last month and a half, Pratt & Whitney [RTX] and the U.S. Air Force Oklahoma City Air Logistics Complex have reduced the number of unavailable F135 engines for the Lockheed Martin [LMT] F-35A below 40, the head of Air Combat Command (ACC) said on Oct. 25.

On Sept. 20, Air Force Lt. Gen. Clinton Hinote, the service’s deputy chief of staff for strategy, integration, and requirements, said that 46 of the Air Force’s 297 F-35As– more than 15 percent–were grounded for engine or engine-related needs, parts or fuel systems, including engines that have not completed depot maintenance (Defense Daily, Sept. 20). Hinote said that number was “not acceptable” and that “we’ve got to do better.”

“A month to six weeks ago, we were down about 46, 48 F135 engines,” Air Force Gen. Mark Kelly, the ACC commander,  said on Oct. 25 during a Mitchell Institute for Aerospace Studies virtual forum. “We’ve made progress on that, and now we’re sub-40. That is testament to the teaming that we have with Pratt & Whitney in our main engine depot at Tinker Air Logistics Center [Oklahoma City Air Logistics Complex].”

“That number going below 40 is not a trivial accomplishment because they’ve gone below 40 at the same time we’re introducing more and more jets every day to the system so it’s more than just a small improvement,” Kelly said. “It’s an exponential improvement, and I expect them to continue that trend of getting toward zero just as soon as we can. But we’ve had to pull some levers to make sure we don’t overconsume our engines for not a good return on training investment. For example, I’ve had to curtail some of our airshow schedule east of the Mississippi unless we can utilize an airplane that’s already in that area. I can’t in good conscience fly two airplanes from Hill [AFB, Utah] all the way to the East Coast and utilize a bunch of flying hours while we have young airmen, whether at Eglin [AFB, Fla.] or elsewhere, who can’t get their training sorties.”

Air Force Secretary Frank Kendall said last month that he is examining ways to reduce F-35A sustainment costs, and such methods look not to involve buying more F-35As than the 1,763 Air Force objective number–a figure that the Air Force is likely to reduce. Sustainment costs have become the Achilles heel for the program, as they have been and are for other, older systems.

Kendall, who spearheaded a two-year production pause for the U.S. Marine Corps’ version of the F-35 as Pentagon acquisition chief during the Obama administration, said that there’s “a lot of room for improvement” in F-35A sustainment costs.

The report on the Senate Armed Services Committee’s (SASC) version of the fiscal 2022 defense authorization bill recommends moving the responsibility of F-35 sustainment from the F-35 Joint Program Office at Naval Air Station Patuxent River, Md., to the Air Force—for the F-35A—and the U.S. Navy for the F-35B and F-35C. “The provision would require the Under Secretary of Defense for Acquisition and Sustainment, in consultation with the secretaries of the Air Force and the Navy, to provide a transition plan to the congressional defense committees not later than February 1, 2022, that would fully transition sustainment responsibilities to the respective services not later than October 1, 2027,” the report says.

While past F-35 sustainment contracts evaluated Lockheed Martin on the aircraft’s mission capable rates, the new, three-year possibly $6.6 billion sustainment contract is to judge the company on full mission capable rates (FMC) for the aircraft and the on-time availability of parts to ensure FMC rates improve. Overall, the Government Accountability Office has said that the F-35’s FMC rate is 54 percent–18 points below the goal.

While the government plans for the F-35 two decades ago called for a start and go aircraft much like a commuter car–aircraft with an availability rate of more than 90 percent, that has been so far a pipedream, and now the program hopes to achieve just a 65 percent availability rate–the aim of programs for older aircraft.

“The squadrons are doing okay,” Kelly said on Oct. 25 of ACC’s F-35As. “Regardless of whether it’s an F-35 squadron or an F-16 squadron in the Guard or an F-16 squadron in the Reserve or an F-16 squadron on active duty, bar napkin math [says] if we run about a 65 percent aircraft availability rate, we’re giving the aviators the training they need, [and] we’re holding the readiness we need, and we have the deployability we need. When you take a squadron and you count the jets you have down for depot or down for maintenance or supply, you come out with a 65 percent aircraft availability. You’re actually doing okay because we can surge up to deploy or into combat above 70 [percent], but I tend to look at 65 percent aircraft availability as pretty much a steady state line that I need to get for my readiness and my training proficiency.”