AD 68-08-02

68-08-02 BOEING: Amdt. 39-590 as amended by Amendment 39-1516. Applies to Model 727 Series airplanes on which the aft trunnion extension has been chrome plated during overhaul. Compliance required as indicated.

An investigation of a recent failure of the aft trunnion extension of a Boeing Model 727 main landing gear outer cylinder (P/N 65-17651) indicates that the failure probably resulted from the use of an overhaul procedure which was not strictly in accordance with the sequence and techniques described by the Boeing Model 727 Overhaul Manual. Since this unsafe condition is likely to exist in other Boeing Model 727 Series airplanes, accomplish the following:

1. Within the next 75 hours time in service after April 12, 1968, unless already accomplished in accordance with superseded AD 68-07-06, or unless inspected in accordance with (3), inspect all chrome plated main landing gear outer cylinder aft trunnion extensions which have been overhauled in a manner other than specifically described by Section 32/12/1 of the Boeing 727 Overhaul Manual for any evidence of cracks. Inspect in areas and in the manner described in Boeing Alert Service Bulletin 32/153 dated March 29, 1968, or later FAA-approved revision.

2. Reinspect each affected main landing gear outer cylinder aft extension in the manner required by (1) at intervals not to exceed 800 landings.

3. The reinspections required by (2) can be discontinued for any outer cylinder aft extension which has been inspected and reworked in the manner described in Paragraph 4 of Boeing Telegraphic Revision 1 dated April 11, 1968, (or later FAA-approved revision) to Alert Service Bulletin No. 32/153, or in an equivalent manner approved by the Chief, Aircraft Engineering Division, FAA Western Region.

4. If cracks are found, prior to further flight, replace the main landing gear outer cylinder with an unoverhauled cylinder or a cylinder which has been overhauled in the manner specifically describedby Section 32/12/1 of the Boeing Model 727 Overhaul Manual or a cylinder that has been inspected in accordance with (3).

5. The results of each initial inspection per (1) by a U. S. air carrier must be reported within three days to the assigned FAA inspector.

6. For the purpose of compliance with (2), subject to acceptance by the assigned FAA inspector, the number of landings may be determined by dividing each airplane's hours time in service since a landing gear outer cylinder was last replaced or inspected, by the operator's fleet average time from takeoff to landing for the airplane type.

7. Replace all overhauled landing gear outer cylinders, which were not reworked in accordance with the provisions of this AD, within the next 1200 landings.

8. The reinspections required by (2) can be discontinued for any outer cylinder when those cylinders are replaced in accordance with (7).

Amendment 39-590 became effective on publication in the Federal Register for allpersons except those to whom it was made effective immediately by telegram dated April 12, 1968.

This Amendment 39-1516 becomes effective upon publication in the Federal Register.

This Amendment (39-1516) supersedes Amendment 39-590 AD 68-07-06.