A US Air Force investigation has concluded that the November 2023 CV-22B Osprey off Japan was caused by a failure in the gear box and errors in the pilot’s decision making.
The crash, which occurred on the afternoon of November 29, 2023 off the coast of Yakushima Island in southwestern Japan, claimed the lives of eight crew members.
The aircraft and the crew were participating in a joint interoperability exercise when the accident happened. Osprey operations were suspended immediately after the crash, and ground orders were lifted months later, on March 8, 2024.
The investigation report, which was released on August 1, 2024 by the US Air Force Special Operations Command (AFSOC), stated that: “the mishap was caused by a catastrophic failure of the left-hand prop rotor gear box that created a rapidly cascading failure of the aircraft’s drive system, resulting in an instantaneous asymmetric lift condition that was unrecoverable by the mishap crew”.
The report added that the AFSOC board president had found that “[the pilot’s] decision-making was causal, prolonging the mishap sequence and removing any consideration of an earlier landing at a different divert location”.
According to the AFSOC, during the period of the investigation process (December 6, 2023 – May 30, 2024), a team of multi-disciplinary subject matter experts examined multiple sources, including interviews, maintenance logs, flight recorder data, briefing materials, and inspection of aircraft wreckage.
The team then assembled a list of the detailed sequence of events surrounding the CV-22 crash to determine the cause.
“The purpose of the investigation was to identify the cause and contributing factors that led to this mishap,” Lt. Gen. Tony Bauernfeind, former AFSOC Commander said in a statement.
“By conducting a thorough review and accident and safety investigations, we hope to provide answers to the families of the Airmen that lost their lives and prevent future occurrences and tragedies,” Bauernfeind added.
