WASHINGTON — Lockheed Martin on Friday announced it halted acceptance flights and deliveries of new F-35 Joint Strike Fighters amid an investigation into the cause of an F-35B mishap on a Texas runway this month.

The halt means Lockheed delivered fewer F-35s than the 148 contractually required in 2022.

“We were on track to meet our delivery commitment” before the F-35B mishap on Dec. 15, Lockheed spokeswoman Laura Siebert told Defense News. “However, given the delivery pause, we delivered 141 aircraft” this year.

The Pentagon and Lockheed Martin also announced Friday they finalized a contract worth up to $30 billion to deliver up to 398 F-35s for U.S. and international customers over the program’s next three lots, from lots 15 through 17. However, the contract only guarantees lots 15 and 16, with an option for lot 17.

The contract will also include the first F-35s for Belgium, Finland and Poland, Lockheed said in a release.

Siebert said Lockheed halted acceptance flights after the Dec. 15 mishap “out of an abundance of caution.” And because those flights must happen before the delivery of newly built F-35s, it had the effect of halting deliveries as well.

Lockheed has since continued to build new F-35s at Air Force Plant 4 in Fort Worth, Texas, the main facility for building the fifth-generation fighters. But through the latter half of December, those newly completed F-35s stayed on the ground.

Siebert said nine new F-35s are now awaiting acceptance flights and deliveries.

Video of the Dec. 15 mishap, which went viral on social media, showed the F-35B hovering not far above the ground before descending, bouncing once and tipping forward. Its nose and wing touch the ground, and it starts to spin around. The pilot safely ejected.

This was a newly constructed F-35B that had not been transferred to the U.S. government. The pilot is in the Air Force and was performing quality checks for the Defense Contract Management Agency at the time.

Naval Air Systems Command is still investigating the mishap, with the support of the F-35 Joint Program Office. But earlier this week, the JPO issued guidance as a result of the incident for a small number of newer F-35s it felt are at higher risk.

In a Tuesday statement to Defense News, the JPO said it “has issued a Time Compliance Technical Directive (TCTD) to restrict some aircraft, which have been evaluated to be of higher risk, from flight operations while the investigation into the mishap on December 15 continues and until procedures can be developed for their return to flight.”

The JPO would not say how many fighters were grounded.

A source familiar with the program told Defense News the investigation into the Dec. 15 mishap found that a tube used to transfer high-pressure fuel in the fighter’s F135 engine, made by Pratt & Whitney, had failed. This discovery prompted the JPO to update its safety risk assessments, which affected jets with fewer than 40 hours of flying.

Pratt & Whitney declined to comment to Defense News on the Dec. 15 mishap because it involves an ongoing investigation.

The latest contract for F-35s could include more fighters than the Pentagon originally estimated. When the handshake agreement was announced in July, William LaPlante, the Pentagon’s chief weapons buyer, said the deal was for about 375 aircraft.

But the maximum order of 398 fighters Lockheed Martin will now build — 145 in lot 15, 127 in lot 16 and an option to build up to 126 in lot 17 — is still 80 fewer than those included in the previous $34 billion contract for lots 12 through 14, signed in 2019.

“The F-35 delivers unsurpassed capability to our warfighters and operational commanders,” Air Force Lt. Gen. Mike Schmidt, the F-35′s program executive officer, said in the Lockheed release. “This contract strikes the right balance between what’s best for the U.S. taxpayers, military services, allies and our foreign military sales customers.”

Lockheed said it has so far delivered 894 F-35s worldwide, including the 141 from this year. Other nations that will receive fighters as part of the latest contract include Australia, Denmark, Israel, Italy, Japan, the Netherlands, Norway and the U.K.

“Continuing to add new countries to our global F-35 fleet further validates the capability and affordability of this aircraft in providing 21st century security to nations and allies,” Bridget Lauderdale, vice president and general manager for Lockheed Martin’s F-35 program. “There is simply no other aircraft that can do all that the F-35 does to defeat and deter even the most advanced threats.”

The average price of an F-35A aircraft vehicle — that is, everything in the fighter except the engine — will increase 6.5% between lot 14 and lot 17, Lockheed said. The company added it was able to hold the cost growth down below the rate of inflation.

The per-unit aircraft vehicle cost for an F-35A was $65.6 million in lot 14, Lockheed said. That cost will increase to $70.2 million in lot 15, before dropping to $69.3 million in lot 16 and then rising again to $69.9 million in lot 17.

Siebert said the government’s contract with F135 engine-maker Pratt & Whitney is not finalized, so the total price for an F-35 including the engine cannot yet be calculated.

This is a shift from the previous contract, which saw several years of declining F-35 costs. The Pentagon said in 2019 the average price per F-35 would fall about 12.8% from lot 11 to lot 14.

Lockheed said several factors have contributed to the increase in costs, including inflation, supply chain issues and other COVID-19 related complications, as well as the reduced number of jets being purchased.

The F-35s being built for lot 15 and beyond will include greater capabilities, most notably the inclusion of Technology Refresh 3 upgrades to the jet’s hardware and software, which Lockheed said is also contributing to the price increase. The TR3 upgrades are intended to improve the F-35′s displays, processing capability and memory, while paving the way for the jet’s Block 4 modernization effort.

“You’re adding capabilities, you’re buying more of a jet now,” Edward Smith, Lockheed Martin’s director of F-35 domestic engagement, told Defense News during a visit to Plant 4 in November. “Your prices are going to go up a bit. You can’t [get the price lower] by cutting ... airplanes out of a lot buy.”

Schmidt touted the increased capabilities that will come with the next batches of F-35s in the release.

“The F-35 is the world’s premier multi-mission, fifth-generation weapon system, and the modernized Block 4 capabilities these new aircraft will bring to bear strengthens not just capability, but interoperability with our allies and partners across land, sea, air and cyber domains,” Schmidt said.

Lockheed said it expects to deliver between 147 and 153 fighters annually over the next two years, although that could change as a result of the delivery pause at the end of 2022.

Stephen Losey is the air warfare reporter for Defense News. He previously covered leadership and personnel issues at Air Force Times, and the Pentagon, special operations and air warfare at Military.com. He has traveled to the Middle East to cover U.S. Air Force operations.

Share:
More In Air Warfare