The FAA has proposed an airworthiness directive (AD) requiring the removal from service of some Superior Air Parts crankshaft assemblies used on all SAP Model IO-360-series and O-360-series reciprocating engines and certain Lycoming engines following three loss-of-power accidents tied to fatigue cracking of the crankshaft assemblies.
The AD, which affects an estimated 115 crankshaft assemblies installed on U.S.-registered normal-category aircraft, includes Lycoming engine models AEIO-360-, IO-360-, and O-360-series engines if they have a Superior Air Parts crankshaft assembly with designated part numbers installed. The crankshaft assemblies were installed as original equipment on the affected Superior Air Parts engines and under parts manufacturer approval on the Lycoming engines, according to a notice published January 29.
The FAA will accept comments from the public on the proposed AD until March 16.
AOPA will insist that the method of compliance required be based on the most cost-effective and least intrusive means possible, while maintaining an equivalent level of safety, he said.
According to the FAA, the estimated cost of a full crankshaft replacement is $14,821.
After investigating three Superior Air Parts crankshaft assembly failures that caused loss of power and “immediate or emergency landings” on March 6, 2017; August 3, 2017; and October 31, 2018, the FAA “determined that the crankshaft assembly failures resulted from the manufacturing process at [Superior Air Parts’] crankshaft vendor during 2012 and 2014.” Analysis determined that all three failures were the result of fatigue cracking, the FAA notice said.
The proposed AD would permit a one-time special flight permit to fly the aircraft to a maintenance facility to comply with the AD. Limitations would include no passengers, VFR day conditions only, and avoiding areas of known turbulence.
Comments on the proposed AD may be submitted by March 16 online or by mail to U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. Please include Docket No. FAA-2018-1077 and Product Identifier 2018-NE-40-AD at the beginning of your comments.