Asiana Airlines Flight 221 collision

NTSB narrative

The Boeing 747-400 was taxiing to Gate N-6, after landing on runway 6R. The flight crew reported to the tower that braking action on the runway was poor. While taxiing to the parking ramp, the captain commented to the first officer that the airplane was skidding. As the airplane approached Gate N-6, ground personnel observed the airplane's nosewheels turn 90 degrees toward the gate, but the airplane continued straight ahead, skidding the nosewheels sideways. Ground personnel heard, and the Flight Data Recorder confirmed, an increase in engine power as the airplane continued past the gate. The airplane was then observed turning right, away from the terminal, and colliding with a parked IL-62M airplane. A cleaning person aboard the IL-62M received minor injuries when she was knocked down by the collision. The crew told the NTSB investigator-in-charge that they did not use brakes until attempting to turn away from the parked airplane. Ground witnesses described the taxi speed as "faster than normal." The maximum ground speed recorded by the on-board recorders was 16 knots. The company flight manual states, in part: "(1) Turning... 10 knots or below (5 knots if wet or slippery)." Snow contamination was recorded by the airport authority commencing 11 hours prior to the accident. The airport "Snow Removal Plan" denotes the lead-in lines to the terminal as a Priority 1-A area. Continuous snow removal operations were being conducted at the time of the accident, with all Priority 1 areas, and numerous Priority II areas being plowed and treated. The lead-in taxi lines to the terminal had been sanded five hours prior to the accident. The ramp area, and the lead-in taxi lines had not been plowed. One hour after the accident, about 2 inches of unbroken snow was on the ramp.

Verbatim NTSB analysis and probable cause from the NTSB dataset