Incident Overview
On June 20, 2023, at approximately 13:01 Japan Standard Time, a serious incident involving two aircraft occurred at Kohnan Aerodrome in Okayama City, Okayama Prefecture. The event was classified as an attempted landing on a runway being used by another aircraft, as per Japan's regulations. The Japan Transport Safety Board investigated.
Aircraft and Personnel
Aircraft A, a Robinson R44 helicopter registered as JA01CG, was operated by Takumi Enterprise Co., Ltd. Aboard were a student pilot (Student Pilot A, age 21) and a flight instructor (Captain A, age 53). Aircraft B, a Cessna 172R registered as JA10AZ, was operated by Okayama Air Service Co., Ltd., with a trainee captain (Captain B, age 20) and an instructor (Instructor B, age 48).
Flight History
Prior to the incident, Aircraft B had taken off from Runway 09 around 12:04 for commercial pilot training. After conducting exercises in a training area, it planned five touch-and-go landings. Around 12:54, Aircraft B reported entering the left downwind leg for its first touch-and-go; the flight service confirmed the runway was clear. The first touch-and-go occurred at 12:56.
Meanwhile, Aircraft A had taken off at 12:45 for private pilot training, completed one traffic pattern, and landed at 12:53. Captain A disembarked, deeming Student Pilot A able to fly solo. Student Pilot A then requested taxi information at 12:57 and was advised to taxi to Taxiway T3. Student Pilot A began air-taxiing but was nervous due to the first solo flight.
Around 12:58, Aircraft B reported for its second touch-and-go and was again told the runway was clear. Student Pilot A did not hear this communication. At 12:59, the flight service informed Aircraft A of traffic on base leg and advised to hold short of the runway. Student Pilot A misread this as "line up and wait." Despite visually scanning, Student Pilot A saw no traffic and entered the runway.
Radio Communications and Go-Around
At 13:01, the flight service visually noticed Aircraft A had entered the runway. It immediately instructed Aircraft B to go around. Aircraft B complied from an altitude of about 500 feet on final approach. Aircraft B climbed to around 800 feet near the threshold and overflew the runway. The flight service then reconfirmed the hold-short instruction with Aircraft A. Student Pilot A acknowledged the mistake and returned to Taxiway T3.
Outcome
There were no injuries to persons and no damage to either aircraft. The flight service had provided clearances; however, Student Pilot A's misinterpretation of the instruction led to the runway incursion. The JTSB investigation focused on the sequence of events and radio communications.