59-17-01 WRIGHT: Applies to All TC18DA and TC18EA Series Engines.
Compliance required as follows: Engine Model TC18EA2-Not later than October 1, 1959. All other EA Series Models and TC18DA Series-At the first overhaul after October 15, 1959, but not later than March 31, 1960, except TC18DA2, TC18DA3, TC18DA4, TC18EA1, TC18EA3, and TC18EA6 engines not later than July 31, 1960.
Instances of propeller shaft cracking through the hydro-oil holes have occurred causing a loss of propeller control. To increase the strength of the propeller shaft and prevent this type of failure, the walls of the hydro-oil holes must be inspected and shotpeened in accordance with the instructions contained in Wright Aeronautical Division Service Bulletins Nos. TC18E-178 or TC18-359.