What happened
On February 3, 2021, a Textron Aviation 172S, registration JA393A, operated by the Japan Coast Guard, was performing a solo cross-country navigation training flight. During the approach to runway 36 at Kitakyushu Airport, the aircraft encountered significant turbulence. While the trainee pilot had previously managed similar crosswind conditions during instructor-led flights, the wind at the time of the incident reached a crosswind component that exceeded the safety limits established for solo operations.
As the aircraft descended toward the runway, it encountered unstable air, likely caused by the hangar wave effect from nearby airport buildings. At approximately 10 feet above the ground, the aircraft began to sink. In an attempt to arrest the descent, the pilot performed a significant nose-up maneuver. Simultaneously, the pilot applied maximum power to initiate a go-around. This combination of a high pitch attitude and sudden acceleration caused the lower part of the aft fuselage to strike the runway surface. The impact ruptured a tie-down ring and left abrasion marks on the pavement. The trainee was uninjured, and the aircraft was able to complete the go-around and land safely.
The investigation
The Japan Transport Safety Board (JTSB) examined flight data from the aircraft's Garmin G1000 integrated flight deck, meteorological reports, and the training protocols of the Kitakyushu Aviation Training Center. Investigators analyzed the vertical acceleration and pitch attitude of the aircraft, noting that the turbulence encountered was severe enough to cause fluctuations in vertical G-loads. The investigation also reviewed the wind conditions, confirming that the crosswind component exceeded the 10-knot limit permitted for solo flight training.
Findings
- The primary cause of the incident was the execution of a go-around while the aircraft was in an unstable attitude at low altitude, leading to the aft fuselage contacting the runway.
- The instability was exacerbated by turbulence encountered immediately before touchdown, which was likely a result of wind flowing around airport structures.
- The pilot and instructor failed to adhere to established safety criteria, as the crosswind component exceeded the maximum allowable limit for solo flight.
- The decision to continue the approach was influenced by the trainee's previous experience with similar winds while an instructor was on board, which led to an underestimation of the risks involved in a solo operation.