Marine Corps Knew About Failing Aircraft Part Years Before It Killed Five In Training Crash, Docs Show

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Micaela Burrow Investigative Reporter, Defense
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The Marine Corps identified a potential solution to a clutch malfunction, which led to the deaths of at least five Marines, more than a decade ago, according to a document obtained by

Not until after the Marine Corps completed a formal command investigation into the June 8, 2022, accident, when five Marines on board an MV-22 Osprey crashed during a training exercise in the California desert, in April 2023 did the service publicly acknowledged the clutch issue, according to New Marine Corps documents show that service and the manufacturer tried several fixes in the years leading up to the deadly accident and determined that a component called the input quill assembly was degraded — 13 years before revealing their findings.

The Air Force grounded its CV-22 Osprey fleet in August 2022 as a precaution after four incidents involving the hard clutch engagement, reported. At the time, the Marine Corps refused to ground their MV-22 version, saying the clutch issue was “common knowledge” and its Osprey pilots were trained to handle any in-flight emergency stemming from the malfunction. (RELATED: Army Orders Stand-Down For All Non-Critical Helicopter Units After Series Of Fatal Crashes)

Of the 15 mishaps involving the clutch problem since the V-22 tiltrotor aircraft entered service, 10 of them involved the Marine Corps’ aircraft, a Marine Corps official told the outlet.

Two Osprey crashes in 2022 killed a total of nine Marines, according to

A Marine Corps document now shows that the Marines identified the input quills, which connects the aircraft engines to its gearbox, as the defective part after the very first MV-22 Osprey incident in 2010, reported.

Then, in February 2023, it finally suspended some V-22 Osprey flights, the outlet reported. A defense official said the military suspected the input quills were wearing out more quickly than anticipated but would not specify how often the part would need to be replaced or how many aircraft the grounding would affect.

The Marine Corps said the first deaths traced to the clutch problem occurred in the June 2022 incident. Its investigation report revealed the input quills were replaced every 800 flight hours but said the service does not know the definitive cause of the problem.

In a hard clutch engagement, the clutch briefly slips and then reengages, damaging some components and causing the aircraft to lurch. Both clutches failed simultaneously in the Swift 11 aircraft, causing the single engine drive system to fail itself, the investigation found.

“It is clear from the investigation that there was no error on the part of the pilots and aircrew and nothing they could have done to anticipate or prevent this mishap,” the Marine Corps wrote after the investigation was released in late July. “They were conducting routine flight operations in accordance with applicable regulations when this catastrophic and unanticipated mechanical failure occurred.”

Marine Corps officials say replacing the input quills amounts to a 99% fix, according to

In addition, the new document says all “in-reporting” Ospreys have been retrofitted.

The Osprey’s manufacturer, Bell/Boeing, tried redesigning the input quills in 2017 and 2022; the first attempt failed and the second is ongoing, reported, citing the new document.

A permanent fix remains elusive as the Marine Corps has not been able to purposefully reproduce the hard clutch engagement.

The Marine Corps did not immediately respond to the Daily Caller News Foundation’s request for comment.

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