Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for certain Airmotive Engineering Corp. replacement parts manufacturer approval (PMA) cylinder assemblies marketed by Engine Components International Division (ECi), used on the Continental Motors, Inc. (CMI) models 520 and 550 reciprocating engines, and all other engine models approved for the use of CMI models 520 and 550 cylinder assemblies such as the CMI model 470 when modified by supplemental type certificate (STC). This proposed AD was prompted by failure reports of multiple cylinder head-to-barrel separations and cracked and leaking aluminum cylinder heads. This proposed AD would require initial and repetitive inspections, replacement of cracked cylinders, and replacement of cylinder assemblies at reduced times-in-service. This proposed AD would also prohibit the installation of affected cylinder assemblies into any engine. We are proposing this AD to prevent cylinder head cracks, engine failure, and loss of the airplane.