Japan’s Ground Self-Defense Force (JGSDF) proactively suspended flights of its MV-22 Osprey fleet following a recent US military report highlighting potential mechanical issues.

The decision to ground the Ospreys came after the release of a Marine Corps report on July 21, which investigated the cause of an Osprey crash in California in June 2022. All five US service members on board lost their lives in the incident.

The investigation revealed that the accident was a result of the pilots losing control due to an unintentional clutch disengagement, followed by a sudden, hard clutch engagement. This unexpected mechanical failure has prompted urgent action to replace relevant components before they reach a predetermined flight hour threshold.

The report recommended the replacement of specific parts to mitigate the risk of accidents, leading to the grounding of 14 tiltrotor transport aircraft at the JGSDF’s Kisarazu camp in Chiba Prefecture on July 22, 2023.

Japan’s Defense Ministry officials have confirmed that they will conduct a thorough assessment of safety measures and implement necessary improvements before allowing the MV-22 Ospreys to resume operations.