Cautions About Use Of Proper Torque When Installing Props

The FAA has released a Special Airworthiness Information Bulletin (SAIB) directed to owners, operators, and maintenance personnel of Cessna Model 172Q airplanes about the potential for installation of the propeller using the incorrect propeller mounting bolt torque. At this time, this airworthiness concern is not an unsafe condition that would warrant an AD, according to the FAA.

This SAIB is the result of a service difficulty report (SDR) from a Canadian operator, which was forwarded by Transport Canada. The FAA has have found that the propeller mounting bolt torque called out in the Cessna Model 172 Series 1977 thru 1986 Service Manual No. D2065-3-13 is incorrect for the Model 172Q airplanes when equipped with the McCauley 1A170E/JFA7658 propeller per Type Certificate Data Sheet 3A12.

The FAA recommends that, until the above Cessna Service Manual is revised, the propeller be installed per the procedures defined in McCauley Owner/Operator Information Manual No. MPC26-02, Revision 2 dated March 13, 2013 or later revision; the “Propeller Removal/Installation” section applicable to one-half-inch propeller mounting bolts.

FMI: SAIB