Airworthiness Directives; Teledyne Continental Motors (TCM) and Rolls-Royce Motors Ltd. (R-RM) Series Reciprocating Engines

We are superseding an existing airworthiness directive (AD) for certain TCM and R-RM series reciprocating engines. That AD currently requires replacement of certain magnetos if they fall within the specified serial number (S/N) range, inspection of the removed magneto to verify that the stop pin is still in place, and, if the stop pin is not in place, inspection of the engine gear train, crankcase, and accessory case. This new AD corrects the range of S/Ns affected, requires the same replacement and inspections, and adds R-RM C-125, C- 145, O-300, IO-360, TSIO-360, and LTSIO-520-AE series reciprocating engines to the applicability. This AD was prompted by our awareness of an error in the previous AD applicability in the range of magneto S/Ns affected and of the need to include certain engines made by R-RM, under license of TCM. We are issuing this AD to prevent engine failure and loss of control of the airplane due to migration of the magneto impulse coupling stop pin out of the magneto frame and into the gear train of the engine.