Page:NTSB Aircraft Accident Report, United Airlines Flight 389.pdf/31

 There was no evidence of an inflight fire or explosion. Only a few small pieces of wreckage were recovered with soot or smoke discoloration. This condition was caused by exposure to burning fuel on the water after impact.

The aircraft was in a clean flight configuration with the landing gear, trailing edge flaps, leading edge devices, and the speed brakes retracted, and all structural components were capable of normal operation prior to impact with the water.

The No. 1 engine was the least severely damaged of the three installed. While the bending of compressor and turbine blades opposite the direction of rotation indicates that the engine was rotating at impact with the water, the condition of the compressor turbine drive shaft, with no noticeable twisting, indicates that deceleration rate was lower than that of the other two engines. The bending of the shaft indicates that there was a considerable side load imposed on the engine when it struck the water. There was no evidence of any lubrication deficiency or bearing operational distress that would have impeded normal engine rotation. There was no evidence of any pre-impact failure, overtemperature operation, or structural failure of this engine before impact. The No. 1 engine was rotating at a higher speed than No. 1 when No. 2 struck the water. This is evidenced by the more severe bending of the compressor and turbine blades in a direction opposite to rotation as well as the twisting fractures of the two compressor drive shafts. There is no evidence of structural failure of the basic engine components prior to impact with the water, nor is there any evidence of lubrication or bearing distress. There is no evidence of an overtemperature condition existing in the engine prior to the accident.