Airworthiness Directives; Honeywell International Inc. T5311A, T5311B, T5313B, T5317A, T5317A-1, and T5317B Series Turboshaft Engines and Lycoming Former Military T53-L-11B, T53-L-11D, T53-L-13B, T53-L-13B/D, and T53-L-703 Series Turboshaft Engines

The FAA is superseding an existing airworthiness directive (AD) 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 AD requires 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 AD also expands the engine applicability, and includes 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 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 issuing this AD to prevent in-flight engine failure and forced autorotation landing.