What happened
On 3 March 2007, a Boeing 767-300 ER, registration V8-RBH, was performing a commercial passenger flight at London Heathrow Airport. During the takeoff roll on Runway 2LS, the flight crew observed the illumination of a brake temperature warning light. Upon reviewing the aircraft's status page, the crew identified that the temperature of the No 1 brake was rising rapidly, moving from level 6 to level 7.
Due to the accelerating heat, the commander decided to reject the takeoff at a speed of approximately 90-100 kt. The aircraft came to a successful stop and vacated the runway onto a taxiway. Following the stop, the brake temperature continued to climb, reaching level 9. As a precautionary measure, the fire services were summoned to spray the wheel with water. There were no injuries to the 189 passengers or 11 crew members on board, and the passengers disembarked the aircraft without incident.
The investigation
Technical examinations focused on the No 1 wheel assembly. The investigation involved a metallurgical analysis of the wheel components. The wheel, which had been installed in December 2006, had accumulated 1,145 flying hours and 205 cycles since its last inspection.
Investigators found that a large, cylindrical portion of the inner hub had detached from the main body. The examination revealed that the inner bearing housing had undergone severe overheating due to contact with the primary section of the inner hub. However, the physical assessment of the damage was complicated by the rapid cooling effect caused by the water applied by emergency responders. The investigation also confirmed that there were no failures present in either the inner or outer bearings.
Findings
- The primary cause of the temperature warning was the failure of the No 1 wheel hub.
- The inner hub had split into two parts, with the bearing housing becoming detached.
- The metallurgical examination suggested the failure was likely caused by fatigue, stress corrosion, or a combination of these factors.
- The precise mechanism of the initial failure could not be definitively established due to the extensive mechanical and thermal damage to the component.