USAir - US Airways

The aircraft experienced an uncontained failure of the high pressure turbine stage 1 disk in the No. 1 engine during a high-power ground run for maintenance. Because of a report of an in-flight loss of oil, US Airways mechanics had replaced a seal on the n°1 engine’s integral drive generator and were performing the high-power engine run to check for any oil leakage. For the maintenance check, the mechanics had taxied the airplane to a remote taxiway on the airport and had performed three runups for which no anomalies were noted. During the fourth excursion to high power, at around 93 percent N1 rpm, there was a loud explosion followed by a fire under the left wing of the airplane. The mechanics shut down the engines, discharged both fire bottles into the No. 1 engine nacelle, and evacuated the airplane. Although both fire bottles were discharged, the fire continued until it was extinguished by airport fire department personnel. The aircraft was damaged beyond repair.