Safety Recommendation
The Australian Transport Safety Bureau recommends that the US
Federal Aviation Administration, as the state of design for Lear
Seigler (TRW Lucas) and Aircraft Parts Corporation (GE Unison) type
starter-generators, examine the circumstances of electrical
discharge damage to the number-1 bearing of Pratt & Whitney
Canada PT6A series engines and develop an appropriate safety
assurance strategy, to reduce the risk of engine failure resulting
from the effects of EDD to the number-1 bearing.