67-03-06 LOCKHEED: Amdt. 39-341 Part 39 Federal Register January 20, 1967. Applies to Models 188A and 188C Series Airplanes Except Those Which Incorporate the P/N 2007-3 Piston in the Main Landing Gear Door Actuating Cylinders.
Compliance required as indicated.
To detect cracking in the radius of the junction of the piston head and piston rod of part number 1662-3, accomplish the following:
(a) Within the next 50 landings after the effective date of this AD, unless already accomplished within the last 50 landings before the effective date of this AD, and thereafter at intervals not to exceed 100 landings from the last inspection until 700 landings after the effective date of this AD has been reached, accomplish the following or an equivalent approved by the Chief, Aircraft Engineering Division, FAA, Western Region.
(1) Inspect visually the MLG door actuating cylinders for indications of loss of hydraulic fluid through the air vent filters of the cylinder. Ref: Item14, Figure 3, Section 32-2 of Electra Parts Catalog.
(2) If leakage is noted during the inspection required in (a)(1) before further flight, comply with the accomplishment instructions of Lockheed Service Bulletin 88/SB-642, Section 2, Part II, Items A through I. Items E and F of the Accomplishment Instructions notwithstanding, replace a cracked P/N 1662-3 piston with a P/N 2007-3 piston, or an uncracked P/N 1662-3 piston with less than 2,050 landings, or an uncracked P/N 1662-3 piston with more than 2,050 landings that has been shot peened in accordance with Lockheed Service Bulletin 88/SB-642, Section II, Item F. Shot peening is not required on previously shot-peened P/N 1662-3 pistons. All P/N 1662-3 pistons with less than 2,050 landings must be shot peened, if uncracked, before the accumulation of 2,050 landings. Those P/N 1662-3 pistons with more than 2,050 landings, if uncracked, must be shot peened before further flight.
(b) Within the next 700 landings after the effective date of this AD, unless already accomplished within the last 700 landings before the effective date of this AD, and thereafter at intervals not to exceed 1,400 landings from the date of the last inspection, comply with the accomplishment instruction required in (a)(2).
(c) The requirements of this AD may be discontinued when the P/N 1662-3 piston is replaced by a P/N 2007-3 piston.
(d) For the purpose of complying with this AD, subject to acceptance by the assigned FAA maintenance inspector, the number of landings may be determined by dividing each airplane's hours' time in service by the operator's fleet average time from takeoff to landing for the airplane type.
(e) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Engineering Division, FAA Western Region, may adjust the repetitive inspection intervals specified in this AD, to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator.
(Lockheed Service Bulletin 88/SB-642 covers this same subject.)
This directive effective January 20, 1967.