December 19, 2025

The U.S. military has recently released a “comprehensive review” regarding a series of major accidents involving Osprey aircraft, stating that reducing existing accident risks takes time, and that the risks continue undiminished.

The review warns that unless adequate measures are implemented to ensure the safety of Osprey operations, a catastrophic event similar to past Class A mishaps will inevitably occur.

The review points out that due to the aircraft’s complex design, maintenance work requires a high number of manhours, and that the operating and maintenance costs of Osprey aircraft have increased by 30% over the past four years. It notes that fundamental improvements to maintenance programs and supply systems are required.

On December 15, the Defense Ministry notified relevant municipalities that the U.S. review will not affect the safety risk assessments of the Osprey aircraft and will not impose new restrictions on Osprey operations.

Citing past fatal incidents, such as the November 2023 crash of a U.S. Air Force CV-22 Osprey off Yakushima Island (Kagoshima Pref.) that killed all eight crewmembers aboard, the Defense Ministry claimed that measures to prevent and respond to similar incidents are already in place.

The explanation contradicts the U.S. review’s assessments and coincides with the completion of the deployment of all 17 V-22s to the GSDF Camp Saga (Saga City, Saga Pref.), as well as with the start of full-scale V-22 operations across the country’s southwest region of Kyushu.

The government of Japan has a policy of accepting U.S. Osprey deployment in Japan as a deterrent. Japan currently hosts U.S. Marine Corps MV-22s, U.S. Air Force CV-22s, and U.S. Navy CMV-22s. The number of Ospreys in Japan is the second largest after the United States.

The Defense Ministry should at the very least provide the Japanese translation of the U.S. comprehensive review to relevant local governments.