Incident Overview
On Thursday, August 26, 2021, at Kumamoto Airport, a serious incident occurred involving two aircraft: a Cessna 172S, registration JA31UK (Aircraft A), operated by the Educational Corporation Kimigafuchi Gakuen (Sojo University), and an Airbus Helicopters AS365N3, registration JA90MT (Aircraft B), operated by the Kumamoto Prefectural Disaster Prevention Fire Fighting Aviation Unit. The incident was classified as a "Landing on a runway being used by other aircraft" under the Ordinance for Enforcement of Civil Aeronautics Act.
Flight History
Aircraft B, conducting a practical pilot examination, had taken off at 12:06 JST and was performing examination maneuvers in the traffic pattern. It was cleared for an option approach at 13:00. Aircraft A, engaged in take-off and landing training for a student pilot, took off from Runway 25 at about 12:59 and entered the south traffic pattern.
At 13:01:51, Aircraft A requested a touch-and-go clearance while on the downwind leg. The air traffic controller (Tower D) instructed Aircraft A to continue the approach and provided traffic information that Aircraft B was turning final. The crew of Aircraft A attempted but failed to visually acquire Aircraft B. The controller later transferred aerodrome control service to another controller (Tower C) at about 13:03.
Aircraft B touched down at 13:03:40 near T4 Intersection, stopped for approximately 20 seconds, then became airborne again at 13:04:33 and began proceeding. Tower C, visually confirming Aircraft B was airborne, issued a touch-and-go clearance to Aircraft A at 13:04:35, applying reduced separation. At that time, Aircraft A was on final approach about 0.5 nm from the runway threshold.
Almost immediately after, Aircraft B descended and touched down again at 13:04:50 as part of an "Aborted Take-off" examination item simulating an engine failure. Tower C then observed Aircraft B taxiing slowly on the runway and prepared to instruct Aircraft A to go around. At about 13:05:00, Aircraft B radioed that it had aborted the take-off and would make a full stop. Aircraft A subsequently executed a touch-and-go landing on the same runway.
Aircraft and Crew
Aircraft A was a Cessna 172S, a single-engine fixed-wing aircraft. The flight crew consisted of a flight instructor (Captain A) in the right seat, a student pilot (Trainee A) in the left seat, and an observer in the rear left seat. Aircraft B was an Airbus Helicopters AS365N3, a twin-engine rotorcraft. The crew included the captain (Captain B) in the right pilot seat, a pilot (Pilot B) in the left seat, and an examiner in the aft left seat.
Communications and Radar Data
ATC communication records, cockpit voice recorder data from Aircraft B, radar track records, and surveillance camera videos were used to reconstruct the sequence. The air traffic controllers involved were Tower D (who handled Aircraft A initially) and Tower C (who took over and issued the touch-and-go clearance).
Investigation
The Japan Transport Safety Board investigated the incident, designated under Article 166-4, item (ii) of the Ordinance for Enforcement of Civil Aeronautics Act as a serious incident. The French Republic, as the State of Design and Manufacture of Aircraft B, participated as an accredited representative.