AD FAA-2009-1156

The FAA is superseding an existing emergency airworthiness directive (AD) 2009-24-52 that was sent previously to all known U.S. owners and operators of TCM 240, 360, 470, 520, and 550 series reciprocating engines. That AD requires before further flight, replacing certain part number (P/N) hydraulic lifters. This AD results from TCM reporting another occurrence of rapid wear on the face of hydraulic lifters, P/Ns 657913, 657915, and 657916, and from the need to expand the applicability of this AD to include the TCM 346 series reciprocating engines and the R-RM IO-240-A reciprocating engines. We are issuing this AD to prevent excessive hydraulic lifter wear, which can result in loss of engine power and loss of control of the airplane.