AOPA and several other aircraft owners’ groups will document to the FAA their concerns and recommendations about an airworthiness concern sheet and corresponding mandatory service bulletin that calls for owners of many Continental Motors IO-520, IO-550, and some IO-470 engines to replace certain camshaft gears—a costly and invasive procedure—before the next engine overhaul.
On April 14 the aviation groups and the FAA held a conference call arranged by AOPA to discuss the implications of Continental Motors upgrading a prior service bulletin to mandatory status. The FAA could potentially use portions of the mandatory service bulletin’s compliance actions as the basis for a corresponding airworthiness directive.
The mandatory service bulletin followed the issuance by the FAA in December 2016 of an airworthiness concern sheet seeking information from aircraft operators about instances of camshaft gear teeth failures. AOPA notified members of the airworthiness concern sheet in this Dec. 20, 2016, report, and encouraged aircraft operators to participate in providing information about their experience with the camshafts.
The process of replacing a camshaft as now recommended would involve significant dismantling of the engine, and in some instances, modification of engine cases to accommodate the replacement camshaft gear.
The American Bonanza Society, Cirrus Owners and Pilots Association, Twin Cessna Flyer group, and Savvy Aviation participated in the conference call, said David Oord, AOPA senior director of regulatory affairs.
“It was a good discussion that provided a better understanding of the issues,” said Oord, noting that the conference focused on identifying, understanding, and quantifying the safety concerns of the airworthiness concern sheet and mandatory service bulletin, and explored ways to best mitigate them.
The participants also will engage Continental Motors in discussions “to better understand the issue from their point of view,” he said.
AOPA will continue to keep members updated on the issue as the association works with the other industry stakeholders and the FAA.
Oord encouraged members to contact AOPA with any feedback and/or input they would like the association to raise with the FAA.