On July 5, 2012, a China Eastern Airlines A319 (registration B2332, flight MU586) mistakenly entered the Runway at Naha Airport in Okinawa, causing a Japan Asia Airways A320 (registration JA01AJ) on final approach to go around. On May 28, the Japan Ministry of Land, Infrastructure, Transport and Tourism (MLIT) released a recent investigation report, so here is a brief summary. The detailed report is here; it is 33 pages long, which isn’t too long, so you can finish it in a while.

The ATC communication log at the time was as follows: 13:22:56 Tower cleared the Asia Airways A320 to land on Runway 18. 23:23 Tower instructed the China Eastern A319: “Hold short of Runway One Eight. Report when ready.” 23:30 China Eastern replied “[Line up and wait,] Runway One Eight, report ready.” However, the voice was somewhat muffled. At this time, the Asia Airways A320 was 3.5 nautical miles from the Runway threshold, at an altitude of 1090 feet. 23:50 China Eastern A319 passed the hold position markings. At this time, the Asia Airways A320 was 2.7 nautical miles from the Runway threshold, at an altitude of 920 feet. 23:58 China Eastern A319 entered Runway 18, turning left while reporting “Ready” to the Tower. 24:01 Tower instructed the China Eastern A319 to “standby”, and simultaneously instructed the Asia Airways A320 to go around. At this time, the Asia Airways A320 was only 2.1 nautical miles from the Runway threshold. 24:12 Tower instructed the China Eastern A319 to “hold position”.

According to the post-incident investigation of the China Eastern pilots, the First Officer was seated in the Captain’s seat and was the PF. The Captain was seated on the right and was the PM. Meanwhile, another pilot in the rear observer seat was responsible for ATC communications. When they switched frequencies to the Tower, the communication between the Asia Airways A320 and the Tower had already ended, so they were unaware of the existence of this landing aircraft. Moreover, all three pilots actually misheard the Tower’s “Hold short of Runway” instruction as “Line up and wait,” and no one thought there was a problem. Additionally, because they were unaware of the landing aircraft, during the pre-entry check, they did not spot the approaching A320, which had already turned on its landing lights. They only learned about the runway incursion after returning to Shanghai and completing the flight.

According to the investigation of the Tower controller, at the time, she was not wearing her headset on her head but was holding it in her hand. She spotted the China Eastern aircraft when it turned onto Taxiway E0. Due to the distance, the discovery was somewhat late. Since it was a foreign airline, she specifically added “Report when ready” when saying “Hold short of Runway One Eight.” China Eastern’s response was not heard clearly, but she felt there was no issue at the time.

According to the analysis in the report, the causes of the incident are as follows:

1. The Tower controller did not wear the headset on her head and heard the pilot’s reply through the speaker. Because Ground Control communication was happening simultaneously nearby, there was potential for interference. Additionally, holding the handset resulted in speaking directly into the microphone, which may have caused noise.
2. The pronunciation of the China Eastern pilots was not clear enough.
3. The controller misunderstood the pilot’s reply.

Improvement Measures

China Eastern

1. Adjusted crew composition based on English proficiency.
2. Conducted technical analysis of the characteristics of English ATC in various countries.
3. Regarding control commands, if there is any ambiguity, strict adherence to procedures is required, and blind obedience is prohibited.

MLIT Since the Tower is far from Taxiways E0 and E1, RWSL (Runway Status Lights) were installed at these locations. The RWSL system issues clear visual signals to aircraft entering a wrong Runway or Taxiway, warning aircraft not to cross or enter a certain line with flashing red lights. The RWSL system consists of Multi-Lateration Systems and radar, capable of automatically determining aircraft positions.

Naha Airport

1. For aircraft waiting before the Runway, provide traffic information and reasons for takeoff and landing to pilots as much as possible.
2. Try to wear headsets to prevent noise caused by breath directly hitting the microphone.
3. Introduce a mutual cross-check mechanism in the future to prevent misjudgment.

Thoughts: It seems that relying solely on voice communication can indeed lead to accidents caused by misunderstanding. If there were red and green lights to command, like ground traffic, the probability of mutual misunderstanding would be greatly reduced.