Document Type: Overhaul Manual Authority: Manufacturer (authoritative directive) Document Number: P&W Part No. 123440

From the Introduction: “This overhaul manual contains the information required for the major overhaul of Wasp Jr. and Wasp engines manufactured by Pratt & Whitney Aircraft of Canada, Ltd., Longueuil, Province of Quebec, J4K 4X9, Canada and the Pratt & Whitney Aircraft, Division of United Technologies Corporation, East Hartford, Connecticut 06108. It is our object to furnish overhaul and repair activities with the most up-to-date knowledge available on the overhaul of these engines. Any specific information not contained in this manual will be gladly furnished by the Pratt & Whitney Aircraft Technical Publications Department, to whom overhaul inquiries should be directed.

Time Between Overhauls - Where engines are consistently cruised at relatively low power, such as in operations involving long range aircraft, and where conservative cruising outputs can be consistently maintained, periods of 1000 to 1600 hours (helicopter engines 500 to 800 hours) (Agricultural aircraft 600 to 1000 hours) between overhauls are feasible, but such extended periods between overhauls should be approached gradually, experience being the deciding factor. Extension of time between overhauls should be determined by experience with the engines of a particular model in the given type of operation, and their condition at overhaul. It is suggested that overhaul period increases be made in increments of 100 flight hours. Oil consumption is usually one of the best indications as to whether or not the engine requires overhaul, provided the engine is performing normally, and there is no indication of possible trouble or irregularities requiring more than normal line maintenance attention. A sudden increase of oil consumption, or a gradual increase of oil consumption to double that which has previously been average, is usually case for overhaul."