AD 68-23-05

68-23-05 LOCKHEED: Amendment 39-688. Applies to all Lockheed Model 188A and 188C airplanes.

(1) Within the next 50 hours' time in service after the effective date of this AD, unless previously accomplished within the preceding 575 hours' time in service, visually inspect, either internally or externally, No. 1 upper wing plank at No. 2 and 3 nacelles from the forward edge of plank No. 1 aft 4 inches and between wing station 168 and wing station 174, except for those portions of that area hidden by spar cap or rib elements, to detect any evidence of cracks originating at that point and extending aft and outboard. Where the required visual inspection cannot be performed because of existing repairs, the prescribed area will be inspected in accordance with an inspection procedure approved by the Chief, Aircraft Engineering Division, FAA Western Region.

(2) If cracks exist, appropriate repair must be accomplished before further flight in a manner approved by the Chief, AircraftEngineering Division, FAA Western Region.

(3) After initial inspection, such inspection shall thereafter be performed at intervals not to exceed 625 hours' time in service.

(4) The repetitive inspection required by (3) may be discontinued upon completion of the appropriate preventive repair installation described in Section I.C.I. or preventive reinforcement of Section I.C.II. of Lockheed Service Bulletin No. 85/SB-665 dated November 11, 1968, (or later FAA approved revision) or upon completion of an equivalent repair approved by the Chief, Aircraft Engineering Division, FAA Western Region.

(5) 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.

Airplanes with cracked wing planks may be flown in accordance with special flight permits issued pursuant to FAR 21.197 to a base where repair can be accomplished.

Effective July 5, 1968.

Revised December 6, 1968.