What happened
On July 20, 2009, a privately owned Robinson R44 II, registration JA32CT, departed Miho Airport for a familiarization flight. The flight was intended to proceed toward Tajima Airport under visual flight rules. During the flight, the pilot reported to flight service that the aircraft was flying above the clouds and was searching for an opening in the weather to facilitate an approach.
As the flight progressed, the aircraft's position reports indicated it was navigating through heavy fog and cloud cover. At approximately 09:29 JST, radar and GPS data showed the aircraft's altitude began to decrease rapidly while it was near the accident site. The aircraft subsequently struck the western slope of Mt. Higashi-tokonoo, roughly 15 kilometers southeast of Tajima Airport. The impact destroyed the aircraft and ignited a fire. Both the pilot and the passenger were killed in the crash.
The investigation
The Japan Transport Safety Board (JTSB) conducted an investigation involving on-site examinations, wreckage analysis, and the review of ATC radar and GPS records. Investigators examined the aircraft's engine, gearbox, and flight instruments, as well as the condition of the Emergency Locator Transmitter (ELT).
Witness accounts from the area described seeing a helicopter flying at a low altitude beneath fog or hearing loud sounds consistent with a high-speed impact with trees. The investigation also analyzed meteorological data, which confirmed that significant cloud cover and fog were present along the flight path, making it difficult to maintain visual meteorological conditions.