Air Force Special Operations Command officials released the results of the investigation of the CV-22B Osprey mishap Nov. 29, 2023, near Yakushima, Japan.
The aircraft, assigned to the 21st Special Operations Squadron, 353rd Special Operations Wing at Yokota Air Base, Japan, was participating in a joint inter-operability exercise when the mishap occurred. The aircrew was comprised of personnel from the 21st SOS, 1st SOS and 43rd Intelligence Squadron.
The next of kin of the eight servicemembers lost in the mishap received in person briefings on the findings of the investigation as well as a copy of the report. AFSOC continues to provide support and resources to the NOK.
An Accident Investigation Board was convened by Lt. Gen. Tony Bauernfeind, then AFSOC commander, to assess the facts and circumstances of the crash to determine its cause. From Dec. 6, 2023, through 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. After an extensive engineering and human factors analysis, the team assembled a detailed sequence of events surrounding the CV-22 mishap to determine cause.
"The purpose of the investigation was to identify the cause and contributing factors that led to this mishap," Bauernfeind said. "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."
The board president found, by a preponderance of the evidence, 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. Additionally, the board president found decision-making was causal, prolonging the mishap sequence and removing any consideration of an earlier landing at a different divert location.
Substantial contributing factors to the mishap, found by the preponderance of the evidence, include inadequate risk management and ineffective crew resource management.
