FAA Airworthiness Concern Sheet: Lycoming IO-360 Engine

The FAA is currently investigating reports of engine shutdowns during throttle reduction to idle, often referred to as rollbacks, on aircraft equipped with Lycoming IO-360 engines. An airworthiness concern sheet (ACS) has been issued to inform operators and maintenance personnel of this concern and to collect additional operational data. 

The ACS was published after multiple reports were received indicatinguncommanded engine shutdownson aircraft with IO-360 engines using AVStar manufactured vertical and horizontal mounted fuel servos when the throttle was brought back toward idle. These events have been reported on a range of aircraft including Cessna 172S, Cessna 172R, Piper Archer III, Piper Pilot 100i, and Piper Seminole models equipped with IO-360 engines. 

The FAA is asking operators, maintainers, and owners of aircraft with IO-360 engines to provide information on any observed rollback events, regardless of fuel servo manufacturer or installation orientation. The requested information can be found here.

The FAA uses the airworthiness concern sheet to communicate and coordinate potential airworthiness concerns to the industry and to gather information about specific issues before they reach the level of required airworthiness actions. EAA, along with other associations and type clubs, disseminates the voluntary ACS as a means to help the FAA gather information and to better understand any mitigating circumstances surrounding each particular issue.