Airworthiness Directives; Teledyne Continental Motors IO-360, TSIO-360, LTSIO-360, O-470, IO-470, TSIO-470, IO-520, TSIO-520, LTSIO-520, IO-550, TSIO-550, and TSIOL-550 Series Reciprocating Engines

This amendment supersedes emergency airworthiness directive (AD) 2000-08-51. Emergency AD 2000-08-51 was sent to all known U.S. owners and operators of Teledyne Continental Motors (TCM) IO-360, TSIO- 360, LTSIO-360, O-470, IO-470, TSIO-470, IO-520, TSIO-520, LTSIO-520, IO-550, TSIO-550, and TSIOL-550 series reciprocating engines by individual letters. This amendment requires removing a core sample of material from the propeller mounting flange of certain crankshafts, and sending the core sample to TCM for evaluation. This amendment is prompted by reports of crankshaft failures, and by the addition of additional crankshaft serial numbers (SN) that have been added to the suspect population. The actions specified by this AD are intended to prevent fracture of the crankshaft connecting rod journal, which could result in total engine power loss, in-flight engine failure and possible forced landing.