F-35C design fix to support AIM-9X missile weight will cost $8.8M

By Lee Hudson / January 5, 2017

A design fix for the F-35C that strengthens the wing to support the weight of the AIM-9X air-to-air missile will cost about $8.8 million, Inside Defense has learned.

The initial cost estimate assumes that flight testing the design fix this month will be successful, according to a Dec. 28 Navy information paper viewed by Inside Defense.

Thirty-two F-35C jets will require the modification and the Pentagon anticipates the retrofits will be completed by the end of 2018, the paper reads.

"The aircraft required for the Initial Operational Test and Evaluation will be completed by Spring 2018 and the Initial Operating Capability aircraft will be completed by Fall 2018," according to the information paper.

F-35 Program Executive Officer Lt. Gen. Christopher Bogdan told reporters Dec. 19 during a media roundtable at his office in Arlington, VA, his team had an "inkling" during the program's modeling and simulation phase there was going to be a problem with the F-35C wing supporting the missile.

If the design fix to strengthen the jet's outer wing is a success during flight testing, it would be a simple modification for C models, according to Bogdan.

"The reason is because the outer wing on the C model comes off like a piece of Lego, it just comes off and you pop it back on," he said.

Inside Defense previously reported flight testing the design fix would begin in November 2016 instead of January 2017. The flight tests will last for about six weeks at Naval Air Station Patuxent River, MD, according to F-35 spokesman Joe DellaVedova.

Last August, J. Michael Gilmore, the Pentagon's director of operational test and evaluation, sent a memo to DOD leadership titled "Achieving Full Combat Capability with the Joint Strike Fighter (JSF) is at Substantial Risk." One of the items referenced in the memo is that during flight testing of the AIM-9X, which is mounted externally on the outermost wing stations, the missile's weight exceeded load capacity during F-35C landings and up-and-away maneuvers caused buffeting.

All JSF variants are planned to be fielded with AIM-9X, but the F-35C is the only model that has weight issues with the weapon.

The load bearing on the F-35C outboard wing when carrying the AIM-9X must be strengthened, according to Gilmore's report.

The proposed design fix increases the outboard wing structure by modifying two structural components, DellaVedova told Inside the Navy in September.

"The updated design has been completed and flight test[ing] to verify performance of the updates will begin in November," DellaVedova wrote in a Sept. 13 statement. "That's why we test. We want to find issues now so the F-35 will be the most lethal multirole fighter the world has ever seen."

Further, in August 2016 the Navy completed its final at-sea developmental test of the F-35C that included the first-ever use of test pilots carrying external weapons on the jet.

Tom "Briggo" Briggs, the air vehicle engineering department head at Naval Air Systems Command, told reporters Aug. 15 aboard the aircraft carrier George Washington (CVN-73) the F-35C carried concrete bombs on three external pylons located on the jet's wings during testing. The concrete is molded to be similar in shape and size of the GBU-12 and AIM-9X.