77-12-05 CHAMPION SPARK PLUG COMPANY: Amendment 39-2923 as amended by Amendment 39-3208. Applies to Part Numbers CH48108 and CH48109 oil filters as installed in aircraft certified in all categories, identified by the following manufacturing date codes, 1A7E and 2A7C for the Part Number CH48108 filters, and 1A7G and 1A7I for the Part Number CH48109 oil filters, except for those affected filters which are identified with the symbol "Insp OK 5G7A" stamped adjacent to the manufacturing date code. The manufacturing date code is located on the outside of the filter housing adjacent to the filter installation instructions. Champion Spark Plug Company Aviation Sales Bulletin No. 77-13 also pertains to this subject.
Compliance required before further flight, unless already accomplished, except that the airplane may be flown in accordance with FAR 21.197 to a base where the removal can be performed.
To preclude possible oil filter malfunction resulting from internal bypass valve failure, remove all applicable filters from service.
Amendment 39-2923 became effective June 24, 1977.
This amendment 39-3208 becomes effective May 12, 1978.