On 20 October 2007, at night, a Boeing 767-300 operated by Air Canada was taxiing for Runway 24L at Kansai International Airport for take-off. Meanwhile, another Boeing 767-300, operated by Japan Airlines, had been given landing clearance and was on approach to the same runway. After an incorrect readback, the Air Canada B767 entered the runway to line up. As a consequence of the runway incursion, the B767 on approach executed a go-around on the instructions of air traffic control.
The following is an extract from Aircraft Serious Incident Investigation Report (AI2009-02), published by Japan Transport Safety Board (Japan Transport Safety Board (JTSB))
"08m:36s The Tower sought confirmation from Aircraft-A [Air Canada Boeing 767] on whether it was ready for departure.
08m:40s Aircraft-A replied, “That’s affirmative.”
Around 08m:40s Aircraft-A stopped short of the runway holding position markings on Taxiway A1, and NWA69 [a flight that was on short final, inbound to land before Aircraft B], which was just before touchdown, passed by.
08m:43s The Tower instructed Aircraft-A, “Roger that. Hold short of runway 24L.” The position of Aircraft-B [Japan Airlines B767] was about 6.5nm away from the 24L threshold at this point.
08m:46s Aircraft-A replied to the Tower, “To position 24L.”"
The Report includes the following reconstruction of the event :
Figure 1: Extract from Figure 1 - Estimated track of aircraft A. Source: JTSB, AI2009-2
There were three pilots in the cockpit of aircraft A: the captain, the co-pilot and a Cruise Relief Pilot They all provided similar description of the event. Here is part of the statement of the captain:
[...] "One aircraft had just landed [NWA69] and another one aircraft was approximately 4 nm on final. There were no lighted stop bars at the hold point and air traffic did not seem heavy. The Tower gave us clearance as “Air Canada 036, to line up and wait runway 24L.” The line up clearance was unconditional. The landing aircraft was clearing the runway. The flight lined up and after waiting for about 1 minute 30 seconds, Aircraft-B inquired if they had landing clearance, so we flashed our lights. The Tower then cleared Aircraft-B to make a go-around. We were instructed to vacate 24L via Taxiway A3. Once clear, the Tower inquired if we had received clearance to enter the runway, we responded, “Absolutely affirmative” (received clearance)."[...]
Extract of the statement of the Tower controller is given below:
[...]"When NWA69 landed, I asked Aircraft-A whether they were ready, and the aircraft replied they were ready. However, considering the facts that Aircraft-A taxied slowly, did not contact the Tower early and its movement was slow because of the long-distance flight, and that it would take time for the landed NWA69 to vacate the runway, I decided not to let Aircraft-A depart before the landing of Aircraft-B.
I instructed Aircraft-A to “Hold short of runway.” Although the read-back from Aircraft-A was not clear at the time, I heard “hold” before “position 24L,” so I made judgments that the aircraft would hold short (of runway), and issued Aircraft-B landing clearance. I instructed NWA69 to contact the Ground.
Aircraft-B said, “Confirm, cleared to land?” so I checked NWA69 and other aircraft on the Tower Display Subsystem (hereinafter referred to as “TDS”), and replied “cleared to land.” I thought the confirmation of clearance was just another confirmation of the issuance of clearance. When […] I looked at the side of 24L, I noticed that Aircraft-A had entered the runway and I instructed Aircraft-B to make a go-around."
According to the information, provided in the report, there were some ground facilities that were inoperative during the event:
[...]"Aerodrome lights were lit in compliance with the specified night luminous intensity based on the weather condition of that night. However, because runway renovation work was under way in the Airport at that time, the following aerodrome lights related to Runway A were inoperative, and aeronautical information had been issued.
- Runway center line light (RCLL)
- Runway touchdown zone light (RTZL)
- Stop bar light (STBL)
- Runway guard light (RGL)
- Taxiway center line light (TWCL)
The Airport has a stop bar system (comprised of STBL, RGL, RCLL, control console, etc.) showing the holding point for taxiing aircraft. However, it was not the condition to be able to operate the stop bar system at the time of the serious incident, due to the suspended use of lights (3) to (5) above."[...]
Further, the report specifies some differences in the phraseologies adopted by the Civil Aviation Bureau of Japan and NAV Canada, concerning lining-up on the runway. Also, it lists the conditions under which the operation of stop bar lights is obligatory.
Some notes are given on the reliability of the Tower Display Subsystem (TDS):
[...]"The ARTS-F [automated radar terminal system - a system to display ATC information, such as flight number, altitude and ground speed] of the Airport has TDS within the control tower, allowing for easy recognition of aircraft on the ground within the airport. However, the system also has weak points, such as that some areas could not be surveyed due to reasons such as being hidden behind a building, that ghost targets may appear due to unnecessary reflection of radio waves, and that the performance deterioration of ASDE [Airport Surface Detection Equipment] is unavoidable during rainfall. Therefore, controllers are frequently required to manually input the aircraft data such as flight numbers for departure targets. Thus, it is difficult to say that TDS can surely display all targets of the aircraft on the ground with data on such aircraft."[..]
Section four of the report gives the probable cause:
[...]"It is presumed that this serious incident occurred as follows: The flight crewmembers of the departure aircraft (Aircraft-A) who was instructed from the air traffic controller to hold short of the runway, read back incorrectly after mishearing the instruction as to enter the runway; and the controller also misidentifying the read-back and not confirming it; accordingly the departure aircraft kept entering into the runway; this made the arrival aircraft (Aircraft-B), which already received a landing clearance from the controller, attempt to land on the same runway as a result."
Section five of the report contains the measures that were either planned or implemented after the event:
- In Canada, the ATC phraseology concerning instruction to enter runway before take-off was changed to conform with the recommendations of International Civil Aviation Organisation (ICAO);
- Civil Aviation Bureau of Japan (CABJ) instructed all ATC facilities once again to bring to the attention of all controllers the importance of read-back and prompt correction. In addition, CABJ made an inspection at Kansai Airport, thus providing a summarised safety report, pointing out measures for immediate deployment as well as items for mid-term future implementation:
- Confirmation of read-back;
- Notice to pilots on exact read-back;
- Measures to diminish human factors related errors;
- Support by ATC system -studies on possible implementation of ground movement system with upgraded capabilities.