AD 2011-25-51 76 FR 77382

We are adopting a new airworthiness directive (AD) for certain Continental Motors, Inc. (CMI) models TSIO-520, TSIO-550-K, TSIOF-550K, and IO-550-N series reciprocating engines. This emergency AD was sent previously to all known U.S. owners and operators of these engines. This AD requires replacing affected CMI starter adapters with starter adapters eligible for installation. This AD was prompted by 5 reports received of fractures in starter adapter shaft gears in certain part number (P/N) CMI starter adapters. We are issuing this AD to prevent failure of the starter adapter gear shaft, leading to an inoperable oil scavenge pump and engine in-flight shutdown.