The Government Accountability Office (GAO) has said that the Lockheed Martin [LMT] F-35 is to have no more than five cannibalizations per 1,000 hours and a maximum of 10 per 1,000 hours, and, while such rates were elevated in 2018, the F-35 program has not disclosed more recent statistics, and GAO said that it does not have updated figures either.

While the sustainment contract for the F-35 has said that the not mission capable for supply (NMC-S) rate is to be no more than 10 percent, that rate has been stubbornly high (Defense Daily, Sept. 30).

NMC-S measures the percentage of aircraft unable to fly because of parts shortages.

In calendar year 2018, NMC-S was 28.6 percent before dropping to 20.1 percent the following year and 15.8 percent in 2020. In 2021, the rate ticked up to 18.6 percent and had increased this year from January through September to 23.6 percent, the F-35 Joint Program Office (JPO) said.

Parts issues have included delays in supplying power modules for the Pratt & Whitney [RTX] F135 engine, but the F-35 program and industry have apparently mitigated that by ramping up depot capacity. In September last year, 46-48 U.S. F-35As under Air Combat Command did not have a working engine, but that number has dropped to five, Air Force Gen. Mark Kelly, the head of ACC, said in September.

“Non-mission capable [NMC] aircraft are not salvaged for parts as a planned source of supply,” the F-35 JPO said on Nov. 8. “When an aircraft is NMC it is possible the owning unit/command could make the deliberate decision to remove components from the downed aircraft to bring another aircraft up to MC status, but that is a local commander’s decision. Due to operational security concerns we will not discuss specific NMC-S issues publicly.”

One factor that could complicate F-35 cannibalization is the aircraft’s low-observable exterior.

In response to questions, the Air Force said in September that the cannibalization rate for the 49 F-35As in the 33rd Fighter Wing at Eglin AFB, Fla., was 1.7 per 100 sorties. Given that training sorties typically last one to two hours, that would mean that the cannibalization rate for the 33rd Fighter Wing is between 8.5 and 17 cannibalizations per 1,000 flight hours—two to three times the program objective.

An April 2019 GAO report apparently revealed the last known data on F-35 cannibalization rates.

“According to prime contractor data, to keep aircraft flying despite parts shortages, from May through November 2018 F-35 squadrons cannibalized (that is, took) parts from other aircraft at rates that were more than six times greater than the services’ objective,” the report said.

Such a statistic would mean that the F-35 cannibalization rate between May and November 2018 was 30 per 1,000 flight hours.

“These high rates of cannibalization mask even greater parts shortages, because personnel at F-35 squadrons are pulling parts off of other aircraft that are already unable to fly instead of waiting for new parts to be delivered through the supply chain,” the 2019 report said.