78-12-08 AVCO LYCOMING: Amendment 39-3239. Applies to O-320-H series engines Serial Numbers L-101-76 through L-3829-76, L-3831-76, L-3843-76 through L-3859-76, L-3864-76, L-3866-76, L-3871-76, L-3902-76 through L-3907-76 and all O-320-H series engines overhauled (Remanufactured by Lycoming) before March 24, 1978.
Compliance required within the next 10 hours in service, unless already accomplished.
a. To prevent oil pump failures, remove, inspect and alter the oil pump body and replace the oil pump driving impeller with driving impeller P/N LW-15998 and the oil pump driven impeller with driven impeller P/N LW-15999 in accordance with AVCO Lycoming Service Bulletin No. 423 dated March 24, 1978, or FAA approved equivalent.
b. Equivalent method of compliance must be approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.
This amendment is effective June 20, 1978.