65-09-04 LOCKHEED: Amdt. 39-59 Part 39 Federal Register April 28, 1965. Applies to Models 188A and 188C Series Aircraft.
Compliance required as indicated.
There have been a number of cracks in the wing upper surface in the area of the main landing gear rib forgings, some of which have extended out from previous crack repairs and from reinforcements.
(a) Within the next 700 landings after the effective date of this AD, unless already accomplished within the last 700 landings prior to the effective date of this AD, accomplished the following or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region:
(1) Inspect the external surface of the upper wing planks visually for cracks in the area bounded by the front spar-to-plank joint and the rear spar-to-plank joint between Wing Station 221 and the nacelle outboard skate angle, and between Wing Station 155 and the nacelle inboard skate angle;
(2) Inspect for cracks by dye penetrant technique, that portion of the external surface of the upper wing plank area located 2.5 inches forward and 2.5 inches aft of the No. 3-to- No. 4 plank joint between Wing Station 221 and the nacelle outboard skate angle and between Wing Station 155 and the nacelle inboard skate angle, which is not hidden by the existing 0.25 inch reinforcing doubler; and
(3) Inspect the tang of the No. 4 plank at the No. 3-to-No. 4 plank joint between Wing Station 221 and the nacelle outboard skate angle and between Wing Station 155 and the nacelle inboard skate angle, for vertical cracks at the tang radius, by either of the following:
(i) Externally by the ultrasonic technique described in Lockheed Service Bulletin 88/SB-620, Section 2.A. (2)(b), pages 5 through 7, or later FAA-approved revision. Visually reinspect internally if cracks are indicated by the ultrasonic inspection.
(ii) Visual internal inspection.
(b) Repair any cracks found during the inspections required by this AD before further flight, in accordance with the Lockheed Electra Structural Repair Manual or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region, except that the aircraft may be flown in accordance with the provisions of FAR 21.197 to a base where the repair can be made.
NOTE: Regional approval required by (b) may be facilitated by obtaining prior approval of a Structural DER.
(c) Reinspect internally by visual means or by X-ray technique any area repaired in accordance with (b) within 1,400 landings after inspection in accordance with (a), and at intervals thereafter not to exceed 1,400 landings from the last inspection. Upon the request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Engineering Division, FAA Western Region, may authorize alternative inspection techniques and intervals for specified repaired areas, provided the request is accompanied by technical data describing the length, location,and disposition of the crack, and the details of the repair.
(d) Reinspect in accordance with (a) all areas found free of cracks at intervals not to exceed 1,400 landings from the last inspection.
(e) When subsequent reinspection shows evidence of growth of a crack repaired in accordance with (b), remove the repair, and repair the engine cracked area in accordance with (b) before further flight except that the aircraft may be flown in accordance with the provisions of FAR 21.197 to a base where the repair can be made.
(f) The repetitive inspections required by (c) for repaired areas and (d) for areas free from cracks may be discontinued if the upper wing planks are inspected, repaired if necessary, and reinforced in accordance with the following:
(1) Inspect for cracks as specified in (a) the areas not hidden by the 0.25 inch reinforcing doubler and not previously repaired;
(2) Inspect for cracks as specified in (c) repaired areas;
(3) Inspect for cracks asspecified in (a) the area hidden by the 0.25 inch reinforcing doubler with the doubler removed;
(4) Repair in accordance with (b) any cracks found; and
(5) Incorporate the reinforcements described by Lockheed Drawings 841314, 841315, SED/64-9010 and SED/64-9011 in accordance with the accomplishment instructions, Section 2.A. through 2.L. of Lockheed Service Bulletin 88/SB-619, or later FAA-approved revision, or equivalent reinforcements approved by the Chief, Aircraft Engineering Division, FAA Western Region.
(g) 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 aircraft's hours' time in service by the operator's fleet average time from takeoff to landing for the aircraft type.
(h) 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.
This supersedes AD 64-25-02.
This directive effective April 28, 1965.