Report: Pentagon grounds Marine Corps version of Joint Strike Fighter

The malfunction occurred just before the plane was about to take off, according to recent news reports. The pilot was able to safely abort the training flight and the failure did not result in any injuries to the pilot or the ground crew at Eglin, Reuters reports. 

Lockheed Martin is the prime contractor for the Air Force, Navy and Marine Corps versions of the F-35. Jet engine manufacturer Pratt & Whitney produce the fighter's single engine on all three variants.

Matthew Bates, spokesman for Pratt & Whitney, told Reuters that a post-flight inspection found a propulsion line inside the engine's exhaust system had come detached, causing the failure. 

"A team of Pratt & Whitney and Rolls-Royce engineers is investigating the cause of the incident and working closely with Lockheed Martin and the F-35 Joint Program Office to resolve the matter," Bates said in a statement issued Friday. 

Rolls-Royce is a main subcontractor on the fighter's jet engine, known as the F135. 

Until the engine issues are resolved, all test flights of the Marine Corps jet — which is designed to take off and land like both a helicopter and a traditional aircraft — have been suspended. 

Friday's setback comes just as program officials with the JSF office and the Marine Corps believed they had turned the corner on the fighter's well-documented history of program delays and cost overrruns. 

In November, service leaders officially created Marine Fighter Attack Squadron 121 at Marine Corps Air Station Yuma in Arizona. The squadron was the first service aviation unit to be made up of F-35 fighters. 

At the time, Sen. John McCainJohn Sidney McCainMellman: Memories may be beautiful, yet… Schumer to oppose Pompeo as secretary of State Arizona GOP blocked from changing rules on filling McCain's seat MORE (R-Ariz.) said the new fighter squadron signified the "overall program is moving in the right direction" despite "many years of frustration and setbacks." 

"The [JSF] program is finally set up to produce more achievable and predictable outcomes," McCain said during a ceremony commemorating the new JSF squadron last November. 

Former Defense Secretary Robert Gates put the program's Marine Corps variant, known as the F-35B, on “probation” and threatened to cancel it unless its cost and schedule problems were fixed within two years.

Late last year, Defense Secretary Leon Panetta officially took the Marine Corps plane off probation. Recent reports, however, claim the JSF, considered the most expensive acquisition program in Pentagon history, is currently $150 billion over budget, based on initial cost estimates.