What happened
On August 26, 2021, at Kumamoto Airport, a serious runway incursion occurred involving two aircraft. A Cessna 172S, registration JA31UK, operated by Sojo University, was performing a touch-and-go training flight. Simultaneously, an Airbus Helicopters AS3KS5N3, registration JA90MT, operated by the Kumamoto Prefectural Disaster Prevention Fire Fighting Aviation Unit, was conducting a practical pilot examination.
As the Cessna 172S was on final approach, the helicopter, which had been cleared for an option approach, decided to execute an aborted takeoff as part of its examination maneuvers. The helicopter touched down and then became airborne again before subsequently landing back on the runway to come to a full stop. During this sequence, the air traffic controller issued a go-around instruction to the Cessna 172S. However, the flight instructor in the Cessna failed to perceive the instruction, and the aircraft completed its touch-and-go maneuver, passing within approximately 920 meters of the stationary helicopter.
The investigation
The JTSB investigation examined cockpit voice and flight data recorders from both aircraft, air traffic control communications, radar tracks, and airport surveillance footage. Investigators focused on why the go-around instruction was not acknowledged and why the helicopter's aborted takeoff was not coordinated in a way that prevented the conflict. The investigation also reviewed the visibility conditions and the level of situational awareness maintained by the flight instructor during the training session.
Findings
- The primary cause was that the pilot of the Cessman 172S was unable to hear the air traffic controller's go-around instruction because the instructor was concentrating on providing technical instruction to the student pilot.
- The helicopter pilot aborted the takeoff to fulfill an examination requirement but had not established specific reporting rules with ATC for such an event.
- The flight instructor in the Cessna 172S had lost situational awareness regarding the position of the preceding aircraft due to a lack of visual contact and a lack of updated traffic information.
- The incident was classified as a Category C runway incursion, meaning there was sufficient time and distance to avoid a collision, though the risk was significant.