64-11-03 LOCKHEED: Amdt. 729 Part 507 Federal Register May 15, 1964. Applies to All Models 188A and 188C Series Aircraft.
Compliance required as indicated.
Cracks have been detected in the upper wing planks on both the inboard and outboard sides of the nacelle where the inboard nacelle skate angles attach to the wing planks. As a result of these cracks, accomplish the following:
(a) Within the next 450 hours' time in service after the effective date of this AD, and thereafter at intervals not to exceed 450 hours' time in service, externally inspect the wing planks in accordance with Section 2.A. of Lockheed Service Bulletin 88/SB-600 or FAA approved equivalent. The external inspections may be discontinued when the internal inspection program prescribed by (b) is initiated.
(b) Within the next 900 hours' time in service after the effective date of this AD, unless accomplished within 2,100 hours' time in service prior to the effective date of this AD, and thereafter atintervals not to exceed 3,000 hours' time in service, internally inspect the wing planks by X-ray or visual means in accordance with Section 2.B. of Lockheed Service Bulletin 88/SB-600 or FAA approved equivalent.
(c) Any cracks found during the accomplishment of (a) or (b) shall be repaired before further flight (except that the aircraft may be ferried in accordance with the provisions of CAR 1.76 to the base at which the repairs are to be accomplished) in accordance with the Lockheed Electra Structural Repair Manual, Section 57-2-1, or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region.
(d) The repetitive inspections of (b) may be discontinued for those aircraft which exhibit no signs of cracks 6,000 hours' time in service after the initial internal inspection is accomplished.
(e) For aircraft on which cracks are detected and repaired in accordance with (c), the repetitive inspections of (b) may be discontinued if no cracks are detected6,000 hours' time in service after the repair is accomplished.
(f) 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 such operator.
(Lockheed Alert Bulletin 88/SB-600 dated June 24, 1963, covers this same subject.)
This directive effective June 15, 1964.