South Korea’s Aviation and Railway Accident Investigation Board has issued its final report into a United Parcel Service (UPS) McDonnell Douglas MD-11 that overran the runway at Seoul Incheon Airport following a rejected takeoff.
The incident occurred on June 6 2016, when the crew on board MD-11 N277UP operating as flight 5X 61 from Seoul Incheon to Anchorage, Alaska, opted to reject the takeoff following tyre damage suffered during the takeoff roll.
The aircraft stopped 350 metres past the runway and suffered substantial damage, including the collapse of the nose gear. One crew member received minor injuries.
While the final report from the ARAIB was published in Korean, The Aviation Herald has translated portions of the report that relate to the probable cause of the accident.
That translation is reproduced here, with minimal editing:
The crew rejected takeoff at high speed at/slightly above V1 due to tyre and drag brace defects at the body gear, the aircraft overran the runway.
- limited time and information available to the captain to assess the situation;
- difficulty for the captain to determine the aircraft’s in flight performance and the dynamic instability of the body gear drag brace following the defect, and;
- decline in braking performance due to the rupture of a hydraulic pipe.
The Aviation Herald report said the aircraft was accelerating on Runway 33L when at about V1 a body gear tyre burst causing damage to the body gear, at about the same time the pilot monitoring called V1 (which was not acknowledged by the pilot flying).
As a result, the acceleration of the aircraft sharply reduced prompting the captain, pilot flying, to reject takeoff due to structural damage.
Then, about 3.3 seconds after accelerating through V1 the engines begin to spool down, the aircraft had reached a maximum of 182 KIAS and was 4,635 feet before the runway end at that time. The ARAIB noted that at the nominal V1 of 169 KIAS the distance to stop needed was computed at 5385 feet.
The body gear indication changed to unlocked and unsafe. Further, the right brakes 1R hydraulic line ruptured, causing the loss of the associated hydraulic system and brakes.
The aircraft overran the end of the runway, broke through the approach lights and the localizer antenna, and came to a stop 485 meters/1,590 feet past the end of the runway. The nose gear collapsed.
More information about the incident can be found on The Aviation Herald website.