Description

On June 2, 2006, an American Airlines Boeing 767-200ER fitted GE CF6-80A engines experienced an uncontained failure of the high pressure turbine (HPT) stage 1 disc in the No. 1 engine during a high-power ground run carried out in designated run up area at Los Angeles for maintenance purposes during daylight normal visibility conditions. The three maintenance personnel on board the aircraft as well as two observers on the ground were not injured but both engines and the aircraft sustained substantial damage from the fuel-fed fire which occurred as an indirect result of the failure.

Investigation

Although there was no intention of flight, an Investigation into the event was carried out by the National Transportation Safety Board (USA) (NTSB). It was established that maintenance were performing a high-power engine run-up in response to a flight crew defect report entered after the previous flight that the left engine lagged behind the right engine by about 2 percent during the climb from FL360 to FL380. The technicians who had been on board reported that they had performed a series of troubleshooting procedures, including deselecting the EEC and then making two rapid movements of the thrust levers from idle to maximum thrust and back to idle. They reported that after the left engine had reached maximum thrust for the second time and was decelerating through 95 percent N1, they had heard a loud explosion that was quickly followed by a fire under the left wing and in the fuselage aft of the wing. They stated that they had immediately shut down both engines, discharged fire shot 1 into the left engine and evacuated the aircraft. The fire continued until it was extinguished by the attending RFFS personnel.