What happened
On 1 March 2005, a Boeing 777-200ER, registration AP-BGL, was taxiing at Manchester Airport after a flight from Lahore, Pakistan. While the aircraft was moving on Taxiway A, a fire was observed in the left main landing gear. The incident was first reported via a radio transmission from an aircraft on an adjacent taxiway, which alerted the airport's Rescue and Fire Fighting Service (RFFS).
Upon arrival, the RFFS Watch Commander observed intense flames emanating from the wheel hub. The commander, acting on the recommendation to evacuate due to the perceived threat of an uncontained fire, ordered the evacuation of the aircraft. During the process, 31 passengers and several fire service personnel sustained minor injuries. The aircraft sustained slight damage to the fuselage skin and heat damage to the No 10 tyre and hydraulic hoses.
The investigation
The investigation focused on the origin of the fire and the efficiency of the evacuation. Investigators examined the left main landing gear and found that the No 10 wheel brake pack showed signs of abnormal heating. Laboratory analysis of the heat shields revealed that the internal ceramic insulation material was heavily contaminated with a volatile organic solvent.
Further examination of the maintenance practices at the operator's overhaul facility indicated that the heat shields had likely been immersed in a flammable solvent during cleaning. This saturation allowed the solvent to escape as a vapour when the brakes reached high temperatures during landing, subsequently igniting upon contact with the hot brake components.
Findings
- The fire was caused by the contamination of the ceramic insulation material within the wheel heat shields with a flammable solvent.
- The solvent likely entered the heat shields during a maintenance process where the components were immersed in a solvent bath.
- The heat generated by the brakes during the landing at Manchester provided the necessary energy to ignite the escaped solvent vapours.
- The evacuation time was prolonged because the cabin crew and passengers were not in a state of high urgency, as the flight had already concluded with 'farewell' announcements.
- The apparent increase in smoke during firefighting was actually caused by water hitting the hot brakes, creating steam that lifted carbon dust.
Safety action
- The operator has retrained maintenance personnel and transitioned to a steam cleaning process for wheel heat shields to avoid solvent immersion.
- The manufacturer has introduced a warning in the maintenance manual regarding the risks of dipping heat shields in flammable solvents.
- The airline recalled all spare wheels to dry any suspect heat shields in an oven.