This article is taken from the October 31 FAAST Blast (Notice Number: NOTC3339)
Bulletin Stresses Proper Performance at Idle for Cessna 172
On October 26, 2011, the FAA issued a Special Airworthiness Information Bulletin (SAIB) that addresses a concern with proper engine performance at idle for 1996 and after Cessna 172R and 172S models. Engine fuel servos on these aircraft have the potential to shift to an over-rich condition with the throttle at idle, which, if not addressed, could lead to the engine’s inability to operate at idle-stop and possibly prevent a restart in-flight. The SAIB stresses the importance of understanding how an engine should properly perform when at idle, and how operators need to review, understand, and adhere to the operating limitations defined in the POH/AFM and maintenance manual.
Cessna has taken action to include information in their service documents and POH updates for these models to address the issue and improve the operator and maintenance communities’ understanding of what proper engine performance should be with the throttle at idle.
You may view or download SAIB CE-12-03 here.