What happened
On April 27, 2009, a Robinson R22 Beta, registration JA7987, was conducting flight training at Yao Airport. The flight, operated by Osaka Aviation Inc., involved an instructor and a trainee performing various maneuvers, including takeoff and landing training with autorotation power recovery.
During a 180-degree turn autorotation power recovery maneuver, the aircraft was flying on a downwind leg at approximately 350 feet. While the crew was managing the descent, the instructor noticed the oil pressure warning light illuminate, indicating the engine had stopped. Due to the low altitude and the presence of a tailwind, the instructor took control of the aircraft and opted for an emergency landing in a nearby grass field to avoid a more severe impact on the runway. The aircraft struck the ground with significant force, resulting in a hard landing. Both the instructor and the trainee escaped the incident without injury.
The investigation
The Japan Transport Safety Board (JTSB) examined the aircraft, the engine, and the flight records. The investigation included interviews with the crew and coordination with authorities from the United States, the state of design and manufacture. Investigators analyzed the engine's condition, the fuel system, and the cockpit instruments, specifically looking for evidence of carburetor icing or mechanical failure. The investigation also reviewed the flight manual's instructions regarding throttle operation and the environmental conditions, such as temperature and humidity, at the time of the accident.