Accident Summary
On Thursday, July 28, 2011, at about 09:22 Japan Standard Time, a Beechcraft A36, registered JA4215, crashed into the slope of Mt. Tsurugi in Memuro-cho, Kasai-gun, Hokkaido. The aircraft was operated by the Obihiro Branch School of the Civil Aviation College and had taken off from Obihiro Airport at 09:11 for a flight training mission practicing basic instrument flight (BIF) in the training and testing area.
Occupants and Injuries
On board were four persons: an instructor serving as captain, two students, and another instructor participating in educational and research flight. Three occupants—the captain, one student, and the other instructor—suffered fatal injuries. The remaining student sustained serious injury. The airplane was destroyed by impact and subsequent fire.
Flight History
According to radar trajectory records and air traffic control communications, the aircraft was conducting VFR BIF training under a hooded student's control. The instructor instructed the student to fly into the mountainous area. The airplane then entered or came close to clouds that covered the mountains, causing the loss of visual ground references. The aircraft approached the ground much closer than the instructor expected. The instructor took over control and attempted to avoid the mountains, but the airplane did not change course to an appropriate direction and collided with the mountain slope.
Probable Cause
The Japan Transport Safety Board determined that it is highly probable the accident occurred as follows: The airplane conducting VFR BIF training, operated by a hooded student, was instructed by the instructor to fly into the mountainous area. It then flew into or close to clouds covering the mountains, losing sight of ground references, and approached the ground very close against the instructor's expectation. The instructor took control and attempted to evade the mountains, but the airplane failed to change to an appropriate course and crashed into the mountain slope.
Additional Findings
The investigation also found it somewhat likely that the instructor intentionally flew close to or into the clouds, though his death prevented clarification of his intentions. It is somewhat likely that the College's basic safety policy was not instilled in field instructors, creating a gap in safety awareness between management and instructors. It is also somewhat likely that the accident involved organizational issues—a work environment or culture that allowed unsafe behaviors. The board also noted that the aircraft was operating under visual flight rules (VFR) and that weather conditions included clouds covering the mountains. The accident site was located on a mountain slope at an elevation consistent with the terrain in the area. The aircraft's weight and balance were within limits, and fuel was adequate for the flight. Post-crash fire consumed much of the wreckage.