A new airworthiness concern sheet (ACS) from the FAA is focusing on cracked throttle levers aboard the Cirrus SR line of piston singles—the SR20, SR22 and SR22T—and asks operators to inspect their in-service aircraft and then provide to the agency information on any damage observed. The August 16, 2024, ACS lists this as an “emergency” for which it requests responses within 10 days. Obviously, that deadline has come and gone, but the agency is likely to be interested in any information submitted on this problem.
According to the ACS, “The FAA recently received a report of a power lever failure on a Cirrus SR20 airplane. While advancing to full throttle in preparation for takeoff, the power lever sheared and the pilot quickly cut fuel to the aircraft and aborted the takeoff. The fleet operator subsequently inspected the remainder of their aircraft and found cracks in 24 of the levers through visual and dye penetrant inspections. Time in service for the fleet ranged from 2900 to 3900 hours. The aircraft are utilized in a training environment and contained an average of 12,000 to 15,000 landings. The failure and cracks were noted to occur at the region of the lever that has the smallest cross section.”
“We recommend operators inspect this area and please provide information including description of damage, available photos, airplane serial number, time in service, and any prior replacement of the throttle assembly or power lever.”
An airworthiness concern sheet is a document the FAA uses to do exactly what it’s doing: Advising of an airworthiness issue and requesting feedback from the field. Of special interest to the agency when an ACS is issued is what, if any, related issues have been encountered through any type-specific organizations. The ACS itself notes that “resolution of this airworthiness concern could involve an Airworthiness Directive (AD) action or a Special Airworthiness Information Bulletin (SAIB), or the FAA could determine that no action is needed at this time. The FAA’s final determination will depend in part on the information received in response to this ACS.”
The throttle lever depicted in the ACS is hollow, allowing for a go-around button installed in later SR models to be wired to the avionics. The throttle levers in early airplanes are solid—no provision for a go-around button—so the older SR-series airplanes may not be affected.
