While the most recently released mission capable (MC) rates for the F-35A, F-35B, and F-35C are below 60 percent, the program said that it has more than satisfied the nine mission man hours per flight hour (MMH/FH) requirement for the aircraft, as the U.S. Air Force F-35A MMH/FH is 4.79, the U.S. Marine Corps’ F-35B 7.48, and the U.S. Navy F-35C 7.55.

The F-35 Joint Program Office (JPO) did not answer questions on how the program has been able to meet the MMH/FH requirement, given that the MC rates for the F-35A and F-35B are just 59 percent and the F-35C 54 percent. The JPO declined to comment on how many F-35s are in “special interest aircraft” (SPINTAC) status. Such planes—those that fail to fly for a month or more–serve as cannibalization parts suppliers for other planes, and, in the past, military squadrons have avoided the SPINTAC red letter mark by having grounded planes fly briefly with a light load or no load just before a month has expired.

The JPO did say that MMH/FH has improved since November, 2018 from 6.01 for the F-35A, 8.23 for the F-35B, and 7.81 for the F-35C.

In declining to answer questions on F-35s in SPINTAC status, a spokeswoman for the JPO said that the program had comprehensively answered a reporter’s earlier detailed email questions on F-35 sustainment issues and could no longer spend time fielding ad hoc follow-up queries.

U.S. military commanders have often praised the advanced technological prowess of the F-35, including its ability to kill adversary aircraft at long range without being seen and to serve as a stealthy reconnaissance/command and control node, but the capacity of DoD to surge sufficient numbers of F-35s in a conflict is unclear.

“The Department [of Defense] in concert with the Joint Program Office continually reviews long term down aircraft ‘hangar queens’ and the factors creating the root cause condition(s) during monthly Product Support Manager sustainment updates,” the Pentagon said in an email response to questions. “Collectively, the department is actively working to determine how it can best influence lasting corrective measures for maintenance drivers and that will improve reliability and availability for the F-35.”

The Government Accountability Office (GAO) is conducting a study of F-35 field level and depot maintenance to include an examination of cannibalization rates and the number of “hangar queen” aircraft–those in SPINTAC status.

Factors that could bring the MMH/FH rate down artificially are if the program only includes field level maintenance in the equation or if the program flies fewer hours.

The “not mission capable for supply” (NMCS) rate–measuring aircraft unable to fly because of parts shortages–also factors in. The F-35 is to have a maximum NMCS rate of 10 percent, but the rate has hovered around 17-18 percent and was 30 percent in 2018.

Air Force Lt. Gen. Eric Fick, the F-35 program executive officer, has said that over the years “decisions to defer spares and the stand-up of organic maintenance have had long reaching impacts on the program,” but he said that, while aircraft availability “is not where we need it to be,” availability rates are headed up, as the military services devote more funds to spare parts and organic depot maintenance.

Last September, 46-48 of the Air Force’s 297 F-35As under ACC were grounded for work on their Pratt & Whitney [RTX] F135 engines, parts or fuel systems, but Air Force personnel at Oklahoma City Air Logistics Center and Pratt & Whitney have reduced the number of unavailable engines below 40 (Defense Daily, Nov. 12, 2021).

“Overall, the F-35 Joint Program (JPO) office is satisfied with the quality of parts provided by suppliers,” the program said in an email response to questions. “There is not a static list of parts that degrade with greatest frequency.  As data indicate degradation of particular parts, the JPO works with our primary contractors – Lockheed Martin and Pratt & Whitney – and their suppliers to assess and address those degraders. If and when we determine that parts are degrading more quickly than anticipated, an action plan is put into place to address.  A few examples of current highest degraders are: engine power modules, electro-optical targeting system (EOTS) window cover, and canopies.”

“One example of how the JPO continues efforts to drive parts quality higher in is in the area of Electronic Equipment Log [EEL] parts data,” the program said. “The JPO works closely with Lockheed Martin and Pratt & Whitney, collecting data weekly to analyze non-Ready for Install (RFI) parts transactions, determine root causes, develop corrective actions, and ultimately resolve issues.  Through these efforts, RFI performance improved from 68 percent in September, 2020 up to 85 percent in November, 2021.”

About 1,000 of the 50,000 parts on the F-35 have required an EEL that designates a given part as RFI and able to be installed on the F-35. The EEL includes part history and remaining part service life in hours. Under the sustainment contracts, Lockheed Martin is required to deliver RFI F‑35 spare parts.

In June 2019, the Pentagon Inspector General said that DoD had spent up to $303 million in labor costs since 2015 for non-RFI spare parts, and in September 2020, the Defense Contract Management Agency (DCMA) and Lockheed Martin agreed on $70.6 million in investments by the company to fix faulty EELs (Defense Daily, Sept. 30, 2020).

While driving the NMCS rate lower would improve readiness, it could also significantly increase costs of acquiring parts from foreign suppliers and transporting those parts to the U.S.

While Congress has broached a consideration of competing Lockheed Martin’s sustainment contract, DoD has not endorsed such a competition. Yet, DoD is examining making F-35 sustainment oversight “organic” to the military services, as for other aircraft programs.

“The Department [of Defense] and Lockheed Martin are collaboratively partnering to deliver performance outcomes that improve both availability and affordability which is currently reflected in the current 2021-2023 annualized sustainment contract,” the Pentagon said. “Furthermore, the department has received a proposal to acquire proprietary provisioning and cataloging technical data from Lockheed Martin that will provide opportunities to transition to organic sustainment in the future.  The department believes that both organic and contractor logistics support will be necessary to sustain the F-35 over the life cycle.”

Lockheed Martin had not responded to questions on the current NMCS rate and how U.S. F-35s are able to meet the MMH/FH requirement by press time on Jan. 25. Defense Daily will update the article if the company responds.

The Pentagon has contemplated using “supply chain hedging” for the F-35 to reduce the NMCS rate. Such hedging, rolled out by the Defense Logistics Agency (DLA) in 2013, would nix parts forecasting and instead use algorithms to produce a spare parts mix for any parts demand level.

“The Department [of Defense] has not pursued supply chain hedging or ‘Alternatives to Forecasting’ for the F-35 program yet,” DoD said.  “While the Defense Logistics Agency has implemented supply chain hedging for consumable parts, the Department [of Defense] and U.S. [military] services are still evaluating implementation for repairable parts.”

Before Lockheed Martin beat Boeing [BA] to win the Joint Strike Fighter (JSF) competition on Oct. 26, 2001, there was concern at top levels of the Pentagon that the “winner take all” JSF acquisition strategy outlined by former Defense Secretary William Perry in 1996 could result in higher acquisition and sustainment costs.

An idea was broached, but never adopted, to have Boeing, if it lost, use its experience with commercial airliners to institute a system to deliver needed JSF parts promptly. DoD acquisition executives looked to Caterpillar, Inc. [CAT] as another model of an advanced supply chain.

Beside sustainment, DoD thought also was given to bringing Boeing on as a second supplier, if Lockheed Martin fell short, and in having Boeing build the F-35 tail section, in part to help retain a minimum of 3,000 engineers as a critical mass on Boeing fighter development, rather than have such talent move on to other “capture” efforts on future contracts.