74-24-11 LOCKHEED-CALIFORNIA CO: Amendment 39-2024. Applies to Lockheed- California Model L-1011-385-1 Series airplanes certificated in all categories.
To prevent possible failure of the main landing gear retract actuator rod due to stress corrosion, accomplish the following:
1. On those airplanes with 2000 or more landings in service on the effective date of this AD, perform an ultrasonic inspection described at 4, below, of the main landing gear retract actuator rod assembly P/N 1523206-101 within the next 130 cycles additional time in service, and at intervals not to exceed 130 cycles thereafter, until an actuator piston rod P/N 1523206-109 is installed.
2. On those airplanes with 1500 to 1999 landings in service on the effective date of this AD, perform an ultrasonic inspection described at 4, below, of the main landing gear retract actuator rod assembly P/N 1523206-101 within the next 260 additional cycles in service, and at intervals not to exceed 130 cycles thereafter, until an actuator piston rod P/N 1523206-109 is installed.
3. On those airplanes with less than 1500 landings in service on the effective date of this AD, perform an ultrasonic inspection described at 4, below, of the main landing gear retract actuator rod assembly P/N 1523206-101 within the next 390 additional cycles in service, and at intervals not to exceed 130 cycles thereafter, until an actuator piston rod P/N 1523206-109 is installed.
4. The ultrasonic inspection required by 1, 2, 3, above, is for surface discrepancies and/or cracks in the main landing gear retract actuator piston rod of the rod assembly P/N 1523206-101, in the area three and one-half inches from the grease fitting. The inspection is to be accomplished per instructions and procedures outlined in Lockheed Service Bulletin 093-32-083, dated November 5, 1974, or later FAA-approved revisions. The rod assembly is part of the P/N 1523122-107 main landing gear actuator assembly.
5. If, as a result of any of the inspections performed per 1, 2, or 3, above, a surface discrepancy and/or crack is discovered, replace the defective P/N 1523206-101 rod with either a P/N 1523206-109 rod or a P/N 1523206-101 rod as may be available in kits, as spares, or in existing spare cylinder assemblies prior to further flight. If a replacement P/N 1523206-101 rod is used, it must be ultrasonically inspected prior to installation, and at intervals not to exceed 130 cycles in service thereafter. Mark defective rods in a conspicuous manner to prevent inadvertent return to service. Installation of P/N 1523206-109 rod constitutes a terminating action for those inspections required by this AD, and operators may return to normal maintenance practices with respect thereto.
6. Definitions. Prior to the effective date of this AD, one landing is considered to be equivalent to one main landing gear cycle. After the effective date of this AD, one cycle consists of the retraction/extension of the gear. An added"Up Cycle" prior to gear extension counts as an additional cycle. Note: Lockheed Service Bulletin 093-32-083 defines cycles in the same manner.
7. After the effective date of this AD, all main landing gear retract actuator rod assemblies, P/N 1523206-101 must be replaced with P/N 1523206-109 rod assemblies prior to accumulation of 7,600 total cycles in service.
8. Equivalent inspections and replacements may be approved by the Chief, Aircraft Engineering Division, FAA Western Region.
9. Airplanes may be flown to a base for the accomplishment of the inspections and replacements required by this AD, per FAR's 21.197 and 21.199.
This amendment becomes effective December 2, 1974.