AOPA filed comments this week opposing a proposed airworthiness directive (AD) against certain Lycoming 360- and 540- series engines that have ECi connecting rods installed. AOPA requested that the FAA withdraw the AD and issue a special airworthiness information bulletin.

"The FAA is basing this AD on one engine failure in which an unrelated problem, possibly an oil blockage, could have caused or contributed to the failure," said Luis Gutierrez, AOPA director of regulatory and certification policy.

"AOPA has found no evidence that shows the engine connecting rods fail to meet safe, FAA-approved limits."

The proposed AD would affect about 2,800 engines, according to the FAA; however, ECi says the number should be much lower. The affected engines are installed in popular airplanes such as Cessna 172s, Beech Sundowners, Grumman Tigers, and several Piper and Mooney models.

AOPA also opposes the FAA's application of automobile standards to aircraft, particularly because this issue has implications for all reciprocating engine connecting rod bores. The FAA used Society of Automotive Engineers standards, but AOPA says a study of the differences between air-cooled (aircraft) and water-cooled (automobile) engines should be done before applying automotive standards to aircraft.

"The FAA has blindsided AOPA, ECi, and the general aviation community in spite of an agreement to utilize the airworthiness concern process to gather all of the GA community input before making a decision as to whether an AD is warranted," Gutierrez said. "The agency should undertake a study that includes industry participation.

FMI: www.aopa.org