NTSB Identification: ANC01IA007
Nonscheduled 14 CFR NORTHWEST AIRLINES INC.
Incident occurred Sunday, October 15, 2000 in ANCHORAGE, AK
Probable Cause Approval Date: 07/02/2001
Aircraft: Boeing 747-251F, registration: N629US
Injuries: 3 Uninjured.
NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.
A Boeing 747 cargo airplane began to taxi for departure. The crew hear a 'thump' type of noise, but attributed the noise to the airplane tires running over a rut. The captain continued taxiing. During the takeoff roll, about 130 knots indicated airspeed (IAS), the captain heard and felt another 'thump', followed by a substantial vibration. The captain said he aborted the takeoff about 148 knots IAS, and applied maximum braking and maximum reverse thrust. The airplane reached 166 knots before beginning to slow. The airplane ran off the paved end of the runway into a clearway consisting of soft dirt, stopping about 486 feet beyond the paved end of the runway as the landing gear wheels sank into the soft terrain. The runway had 11,584 feet of pavement available for use. About 1,500 feet from the beginning of the runway, a large amount of shredded tire debris, along with gouge marks consistent with tire wheel rims, were found on the runway. At the point of rest, the number 11, and number 12 tires, installed as the two aft tires on the right body landing gear assembly, were shredded and destroyed. Tires one through four, were inflated and undamaged. The number five tire was cut, torn and flat. Tires six, seven and eight, were flat. Tires nine and ten were still inflated. Tires 13, 14, 15, and 16, were flat. The nose wheel tires were undamaged and inflated. The airplane also received damage to the underside of the right flap assembly, damage to the right main landing gear hydraulic brake system, a landing gear door, and damage to the brake assemblies. The airplane's takeoff gross weight for the flight was 794,200 pounds. For takeoff operations on the runway utilized, the runway takeoff gross weight was 795,300 pounds.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: Rupture and disintegration of main landing gear tires during the takeoff roll, and subsequent damage to the right main gear hydraulic brake system. Full narrative available
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