AD 81-24-06

81-24-06 TELEDYNE CONTINENTAL MOTORS: Amendment 39-4260. Applies to Models IO-520, TSIO-520 and GTSIO-520 (except GTSIO-520-F and K) engines equipped with engine driven fuel pumps serial numbers I0178XX through A0280XX, factory new or rebuilt engines which were assembled between September 1, 1978, through July 31, 1980, or fuel pumps which were replaced during that time. The first characters of the fuel pump serial numbers reflect the date of manufacture. The first letter designates the month of manufacture starting with "A" for January, "B" for February, etc. The second and third digits designate the day of build (01 thru 31). The fourth and fifth digits indicate the year of build. Subsequent digits indicate manufacturing sequence number of pump on a given day. Compliance required as indicated unless already accomplished. To prevent possible fuel leakage and potential fire hazard, accomplish the following: (a) Within 10 hours time in service after the effective date of this AD and thereafter at intervals not to exceed 10 hours time in service until (b) is accomplished, visually check the fuel pump for evidence of fuel leaks from between the pump segments. If a leak is detected or fuel stains are present, (b) must be accomplished prior to further flight. (b) Within 50 hours time in service after the effective date of this AD, accomplish the following: (1) Remove safety wire from the four fuel pump through bolts. (2) Torque the through bolts evenly in diagonally opposite pairs to 30 in-lbs. ( 1 in-lb.). (3) Resafety wire through bolts. (4) Upon completion of the above steps, place mixture control in "idle cutoff," pressurize the fuel system with the aircraft boost pump, and inspect for fuel leaks. If a fuel leak still exists, overhaul or replace the pump as appropriate. (c) If fuel leaks were present before retorquing the bolts as required in paragraph (b), then during each of the next five preflights, place the mixture control in "idle cutoff," pressurize the fuel system with the aircraft boost pump and check for fuel leaks or evidence of fuel leaks. If evidence of a fuel leak exists, overhaul or replace the pump as appropriate. This paragraph does not apply if the fuel pump was overhauled or replaced due to compliance with paragraph (b). (d) The checks required by paragraphs (a) and (c) may be accomplished by a certificated pilot as authorized by FAR 43.3(h). (e) Make appropriate maintenance record entries. Upon submission of substantiating data through an FAA Aviation Safety Inspector, the Chief, Engineering and Manufacturing Branch may adjust the inspection intervals. An equivalent method of compliance may be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Southern Region. Teledyne Continental Motors Service Bulletin M-80-26, Revision 1, applies to this subject. This amendment becomes effective November 23, 1981.