F-35A Training

A F-35 Lightning ll from the 388th Fighter Wing, Hill Air Force Base, Utah, flies over the Utah Test and Training Range ( US Air Force)

WASHINGTON — The Pentagon has temporarily stopped accepting engines for the F-35 joint strike fighter while it investigates the cause of a mid-December crash of an F-35B jet.

“Currently, acceptance of new engines has been suspended,” JPO spokesman Chief Petty Officer Matthew Olay said in a statement. “That pause began Tuesday, Dec. 27. The length of the pause is currently to be determined, and it is hard to say how long it will last given the current investigation of what specifically would allow deliveries to resume. The root cause analysis and accident investigation need to be completed first.”

The suspension was first reported by Defense News. The engines of the stealthy jet are produced by Pratt & Whitney, a subsidiary of Raytheon Technologies. A spokesperson for Pratt did not respond immediately to a request for comment.

The suspension is a direct result of a Dec. 15 incident, dramatically captured on film, in which an F-35B attempted to land before it began to go out of control. The pilot ejected safely but the plane sustained heavy damage.

Military And Lockheed Ink $30 Billion Deal For Hundreds of Jets

The engine news follows a Dec. 30 announcement that the JPO and Lockheed Martin have finalized a $30 billion agreement on the next two lots of F-35 joint strike fighters, with an option for a third lot included. The deal covers 145 aircraft for Lot 15, 127 for Lot 16, and up to 126 for the Lot 17 contract option, which would include the first fighters for Belgium, Finland and Poland.

On July 18, the two sides announced a “handshake” agreement, which would cover roughly 375 aircraft. However, details remained to be hammered out, a process that apparently took the rest of the year and includes an increase to 398 jets. That’s par for the course with this particular set of negotiations, which stretched for over a year just to get to the handshake.

“The F-35 delivers unsurpassed capability to our warfighters and operational commanders,” Air Force Lt. Gen. Mike Schmidt, the head of the F-35 Joint Program Office, said in a statement. “This contract strikes the right balance between what’s best for the U.S. taxpayers, military services, allies and our foreign military sales customers. The F-35 is the world’s premier multi-mission, 5th-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.”

“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,” added Bridget Lauderdale, Lockheed’s vice president and general manager for the F-35. “There is simply no other aircraft that can do all that the F-35 does to defeat and deter even the most advanced threats.”

Unit prices for the F-35A conventional takeoff and landing model — the most popular of the three F-35 designs, and the one that serves as a barometer of overall unit cost on the program — hit an all-time low in Lot 14 at $78 million. The exact unit price for the F-35A has not been determined, as this contract does not cover the costs of the Pratt-provided engines. However, officials have been saying they expected the unit price to grow in the next order lot, thanks to a combination of COVID-19 impacts on the supply base, rising inflation and a smaller order in this lot when compared to previous negotiations.

“I can’t look at you in the eyes and tell you I’ll get back below $80 million,” Greg Ulmer, who leads Lockheed’s aeronautics business, told Breaking Defense in the fall. “But I do think there’s opportunity space … to keep cost out of the airplane.”

Notably, these lots will be the first to include Technical Refresh-3 (TR-3), a suite of modernized hardware needed to power upcoming Block 4 capabilities. TR-3 — comprised of a new integrated core processor, memory unit and panoramic cockpit display system — has faced delays and cost overruns in the past.

According to Lockheed figures, there are 894 F-35s around the world, spread across 17 countries. “To date, more than 1,870 pilots and 13,500 maintainers have been trained, and the F-35 fleet has surpassed more than 602,000 cumulative flight hours,” the company claims.