The FAA has issued an emergency airworthiness directive (AD) for all Teledyne Continental Motors (TCM) 240-, 360-, 470-, 520-, and 550-series reciprocating engines, effective immediately.
The emergency AD, issued Nov. 16, and amended Nov. 18 to include 550-series engines, requires determining if certain hydraulic valve lifters, part numbers 657913, 657915, and 657916, are installed, and replacing those lifters if they are installed. It results from TCM reporting three occurrences of rapid wear on the face of those hydraulic lifters at 5, 6, and 38 hours time in service. This condition, if not corrected, could result in loss of engine power and loss of control of the airplane.
Owners and operators of aircraft with affected engines must comply with the AD before further flight. If your engine was manufactured or rebuilt before June 19, 2009, and you have not had any hydraulic lifters replaced after June 19, 2009, no action is required.
A mandatory service bulletin issued by TCM Nov. 3 describes procedures for inspecting engines for hydraulic lifters and replacing the lifters if necessary. Warranty information and a list of affected engine serial numbers are in the service bulletin.