Incident Overview
On 29 September 1998, at 0940 UTC, a Boeing 747-400, registration 9M-MPD, was being pushed back from Stand J8 at London Heathrow Airport. The auxiliary power unit was unserviceable, so engines No. 1 and No. 4 had already been started. During the subsequent start sequence for the No. 3 engine, ground crew observed a fire in the jet pipe and immediately alerted the commander.
Passengers' Evacuation
Although no evacuation command was given, a passenger seated towards the rear of the cabin left his seat and opened door 5L (the rearmost left-hand door). This triggered a 'door open' indication on the flight deck. The door slide deployed, and the passenger used it to leave the aircraft, followed by a number of other passengers. Ground crew immediately informed the flight deck of the evacuation in progress. Concerned about the potential danger from jet efflux, the pilots shut down all engines. Airfield Operations personnel, airline staff, and the tug crew attempted to make the evacuated passengers lie on the ground until the danger ceased. Two passengers suffered minor injuries. All evacuated passengers were taken into the terminal via Stand J6, and the passenger who opened the door was later interviewed by police.
Damage and Repairs
The Airfield Fire Service arrived promptly and confirmed that the jet pipe fire had extinguished. The aircraft was then prepared for return to the stand, where the crew and remaining passengers disembarked normally. The fire caused damage to the right-hand high-speed aileron and the right/outboard aft flap section, both of which required replacement. The No. 7 'boat fairing' was removed in accordance with the Minimum Equipment List. Temporary repairs were needed for the right/outboard mid and fore-flap sections. The aircraft departed several days later.
Investigation
The investigation of the No. 3 engine was coordinated with the airline's maintenance base in Malaysia. No indications from the aircraft's Central Maintenance Computer suggested any engine limitations had been exceeded. A manual start on the engine was conducted successfully, and the engine ran normally. As a precaution, the fuel management unit, electronic engine control, and fuel pump were all replaced before the aircraft was dispatched with 'auto start inoperative' placards on the flight deck. The removed components were forwarded to their respective manufacturers for examination. The auto start system was later reinstated and operated satisfactorily. It is considered possible that the fire occurred as a result of pooled fuel from the previous shutdown, but the engine manufacturer had not yet reported whether any defects were found in the removed components.