Summary
The FAA proposes to supersede an existing airworthiness directive (AD), AD 98-22-11, for AlliedSignal, Inc. T5317A-1 turboshaft engines. That AD currently requires repetitive engine fuel pump pressure tests of certain fuel control regulator assemblies to determine if both fuel pumps in the fuel control regulator assemblies are producing fuel pressure. That AD also requires replacing the fuel control regulator assembly, if necessary. This proposed AD would require initial and repetitive visual and dimensional inspections of fuel control regulator assembly main and secondary drive shaft and pump gear splines, installed in certain fuel control regulator assemblies. This proposed AD would also expand the engine applicability, and include certain engines installed on helicopters certified under Sec. 21.25 or 21.27 of the Code of Federal Regulations (14 CFR 21.25 or 14 CFR 21.27). This proposed AD results from several reports of loss of fuel flow from the engine fuel control regulator assembly due to failure of both main and secondary drive shaft and pump gear splines. We are proposing this AD to prevent in-flight engine failure and forced autorotation landing.