Marines of Marine Aviation Weapons and Tactics Squadron 1 prepare for flight aboard an MV-22B Osprey at Marine Corps Air Station Yuma, Ariz., on April 8, 2022.

Marines of Marine Aviation Weapons and Tactics Squadron 1 prepare for flight aboard an MV-22B Osprey at Marine Corps Air Station Yuma, Ariz., on April 8, 2022. (Ruben Padilla/U.S. Marine Corps)

WASHINGTON – A mechanical failure of the clutch in a MV-22 Osprey caused the crash that killed five Marines in June 2022, a service investigation revealed Friday.

“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 said in a statement. "They were conducting routine flight operations in accordance with applicable regulations when this catastrophic and unanticipated mechanical failure occurred.”

The report also ruled out any issues with weather, birds or other external factors. The investigation concluded there should be no disciplinary actions or administrative actions against any Marines.

The Marine Corps had not previously released specifics about the crash that killed the Marines on June 8, 2022, during a training flight near Glamis, Calif., a remote desert area in Imperial County about 35 miles north of the border with Mexico and 50 miles west of Yuma, Ariz.

The crewmen who died were Capt. Nicholas Losapio, 31, and Capt. John Sax, 33, Cpl. Nathan Carlson, 21, Cpl. Seth Rasmuson, 21, and Lance Cpl. Evan Strickland, 19.

“The loss of these five Marines is tragic and, while there will always be inherent risk in military aviation, we are working tirelessly to identify and mitigate risk across the V-22 platform,” said Col. Brian Taylor, a program manager for the Ospreys.

The Osprey is a hybrid aircraft that takes off and lands like a helicopter, but during flight it can rotate its propellers to a horizontal position and cruise like an airplane. Versions of the aircraft are flown by the Marine Corps, Navy and Air Force.

The more than 400-page report found the cause of the crash was due to the failed engagement of aircraft’s dual clutch. When the clutch failed, the aircraft was then unable to thrust with the proprotor on the right side of the Osprey. This caused “unrecoverable departure from controlled flight,” the service said.

A “hard clutch engagement” happens when the clutch in the gearbox that connects one of aircraft’s two engines to the propeller rotor slips and then suddenly reengages, causing the aircraft to lurch.

The report said there were no direct witnesses to the accident, and due to the fiery crash, the data recorder was not recovered.

The investigation also found there have been 16 similar clutch problems with the Marine Ospreys in flight since 2010.

The clutch problem with Ospreys forced the V-22 joint program office in February to ground an undisclosed number of the aircraft across the military services. It was at that time that they began replacing a piece of equipment on the aircraft. The office said Friday that it has eliminated the risk of a similar clutch malfunction by 99%.

The Associated Press contributed to this report.

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Matthew Adams covers the Defense Department at the Pentagon. His past reporting experience includes covering politics for The Dallas Morning News, Houston Chronicle and The News and Observer. He is based in Washington, D.C.

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