What happened
On July 5, 2012, at approximately 13:24 JST, a runway incursion occurred at Naha Airport involving two aircraft. An Airbus A319-112, registered B2/332, operated by China Eastern Airlines Co., Ltd., was taxiing toward Runway 18 for a scheduled departure to Shanghai. Simultaneously, an Airbus A320-214, registered JA01AJ, operated by AirAsia Japan Co., Ltd., was on its final approach to the same runway as part of a flight test operation.
While the air traffic controller instructed the China Eastern aircraft to hold short of the runway, the crew of B2332 entered the runway. This unauthorized entry placed the aircraft in the path of the arriving JA01AJ, forcing the controller to immediately command a go-around. The arriving aircraft climbed away from the runway to avoid a collision. There were no injuries or damage to either aircraft, though the incident involved 27 people on board B2332 and 38 personnel on board JA01AJ.
The investigation
The Japan Transport Safety Board (JTSB) examined air traffic control communication transcripts, radar tracking data, and digital flight data recorder records. The investigation also included interviews with the flight crews of both aircraft and the air traffic controllers involved. Investigators focused on the sequence of radio communications between the ground and tower controllers and the specific instructions relayed to the departing crew.
Findings
The investigation determined that the primary cause of the incident was that B2332 entered the runway despite receiving a hold-short instruction. This was driven by a misunderstanding of the radio instruction by the flight crew, who misheard the instruction to hold short as an instruction to line up and wait. The crew's error was compounded by their inability to visually identify the arriving aircraft on final approach.
Several contributing factors were identified:
- The flight crew of B2332 failed to recognize the error in their readback, and the air traffic controller did not identify or correct the incorrect readback.
- Noise interference during the transmission may have contributed to the crew mishearing the controller.
- The air traffic controller was monitoring the communication via a loudspeaker rather than a headset, which hindered the ability to detect the incorrect readback.
- The controller's perception was influenced by an assumption that the aircraft had acknowledged the instructions correctly, and the readback itself was unclear.