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Report: Boeing 737-900 serious runway excursion incident when crew misinterprets taxi clearance
30 January 2015
HL7759 at the runway end (JTSB)

HL7759 at the runway end (JTSB)

A Japanese incident report reveals that the crew of a Korean Air Boeing 737-900 mistook the runway end lights at Niigata Airport or stopbar lights, causing a runway excursion. 

On August 5, 2013, Korean Air flight KE763 took off from Incheon International Airport, South Korea at 18:09 hours and proceeded towards the destination of Niigata Airport in Japan. The captain was Pilot Flying. The flight was uneventful until landing. The aircraft touched down on runway 10 and decelerated. After landing the controller cleared the flight to exit the runway at the end: “Korean Air seven-six-three, turn right end of runway Bravo one and taxi to spot cross runway zero-four/two-two.” This was read back as follows: “Cross runway 04/22, end of runway right turn.”
The flight crew got the impression that they would cross 04/22 first and then make a right turn. The red lights at the end of the runway were misinterpreted to be stop bar lights and the crew assumed they could continue past those lights. The pilot applied full brakes, but the nose gear departed the runway and the aircraft came to rest with the main gear on the edge of the runway and the nosegear in the grass.

Probable Causes:
It is highly probable that this serious incident occurred when the Aircraft landed on runway 10 in Niigata Airport, the Captain did not let the Aircraft reduce enough lower speed to approach the runway threshold lights that the Captain understood as the stop bar lights for the intersecting runway 04/22, which the Captain was holding a doubt, and when the Captain realized there was no runway beyond the red lights, the Aircraft could not stop within the runway anymore, resulting in overrunning.
It is highly probable that the reasons why the Captain understood the runway threshold lights as the stop bar lights for the intersecting runway 04/22, and why the Captain did not let the Aircraft reduce enough lower speed to approach the lights, are as follows:
(1) Both the Captain and the F/O presumed that the ATC instruction “cross runway 04/22” from the Niigata Tower was “the clearance to cross the intersecting runway during landing roll” rather than “the taxi clearance including crossing the intersecting runway after vacating the runway,” unable to understand the intention of the instruction, and both of them believed the Aircraft was short of the intersecting runway.
(2) The Captain was going to roll to the end of the runway; therefore, he disarmed the autobrakes as fast as about 70 kt. After that the Captain could not take appropriate control of reducing speed with manual braking, even though he should have reduced speed in a careful manner.
It is also somewhat likely that the following reasons contributed to the occurrence of this serious incident:
– The Captain and the F/O were not familiar with Niigata Airport which had an intersecting runway, and they had difficulty to identify the intersecting position with runway 04/22 because ground objects and others which pilots could observe during night landing were limited. In such circumstances, it was difficult for them to judge the speed of the Aircraft in the low speed area in which they did not count on the airspeed indicator.

More information:

Niigata runway diagram (JTSB)

Niigata runway diagram (JTSB)