84-19-03 R1: Cylinder Assemblies

84-19-03 R1 AVCO LYCOMING: Amendment 39-4907 as amended by Amendment 39-4921. Applies to Avco Lycoming model TIO-540-V2AD engines Serial Numbers L-8620-61A and below and model LTIO-540- V2AD Serial Numbers L-2820-68A and below, having P/N LW-18852 cylinder assemblies. These engines are installed in Piper PA-31P-350 "Mojave" aircraft. Compliance is required as indicated, unless already accomplished. Cracks have occurred in the area of the intake valve seat of the cylinder head in the above engine models. To prevent possible failure of the engine cylinder assembly, P/N LW-18852, accomplish the following: (a) Within the next 50 hours of time-in-service after the effective date of this AD, or prior to accumulating 550 hours time-in-service, whichever occurs later, replace all P/N LW-18852 cylinder assemblies with P/N LW-19281 cylinder assemblies which are included in kit P/N LW-19297-S. Cylinder part number identification is located on the cylinder head casting in the rockerbox area. (b) In accordance with FAR 21.197 and 21.199, the aircraft may be flown to a location where the inspections or alterations required by this AD can be performed. (c) An equivalent means of compliance with the requirements of this AD may be approved by the Manager, New York Aircraft Certification Office. Amendment 39-4907 becomes effective on September 20, 1984. This Amendment 39-4921 becomes effective on September 20, 1984.