The Joint Program Office (JPO) estimates that continued development of the F-35 to deal with evolving threats and changing warfighting environments will cost the U.S. government more than $1 billion a year between 2018 and 2024.

The figure came to light during testimony from Vice Admiral Mathias Winter to the U.S. House Armed Services Committee on 7 March.

In total, JPO estimates that continuous capability development and delivery (C2D2) of the F-35 will cost $16.4 billion over that seven year time period, with some $11 billion going toward development and $5.4 billion toward procurement.

Vice Admiral Winter, who leads JPO, said development costs will be shared with U.S. allies, leaving the Department of Defense on the hook for $7.2 billion.

U.S. Rep. Nicola Tsongas said she requested the estimate from JPO after not being able to pin down an official baseline cost for the program.

“This potential cost of $16 billion is an astonishingly high amount and, as far as I am aware, greatly exceeds any cost figures previously provided to congress,” said Tsongas in the hearing.

“The cost of the follow-on effort to improve the capability of the F-35, mostly through software upgrades, has been exceedingly difficult for Congress to nail down over the past several years. If Congress agrees to support this effort at this cost and under the proposed management regime, it should only do so fully aware of the significant risks involved.”

The $7.2 billion for development would be spent to continue improving the F-35 aircraft, its mission data files, autonomic logistics information system, simulators, threat databases, mission planning and reprogramming laboratories, said Vice Admiral Winter. Procurement costs would be for modification kits to upgrade the fighter – not to buy more aircraft, according to the office of Rep. Tsongas.

Development costs in excess of billion dollars a year come as Vice Admiral Winter boasted in his written testimony that the price of the F-35A fell below $100 million for the first time in LRIP Lot 10 to $94.3 million, a 7.5 percent decline from Lot 9 aircraft. Prices for production aircraft are expected to continue to decline as JPO continues to negotiate Lot 11, he wrote.