AD 65-15-04 ACTIVE

65-15-04 LOCKHEED: Amdt. 39-100 Part 39 Federal Register June 30, 1965. Applies to Models 188A and 188C Aircraft.

Compliance required as indicated.

As a result of cracks occurring at the lower No. 4 wing plank drain hole adjacent to Wing Station 159.6, accomplish the following:

(a) For those aircraft with 5,000 or more hours' time in service as of the effective date of this AD, comply with (c) within the next 150 hours' time in service unless accomplished within 850 hours' time in service prior to the effective date of this AD, and thereafter at intervals not to exceed 1,000 hours' time in service from the last inspection.

(b) For those aircraft with less than 5,000 hours' time in service as of the effective date of this AD, comply with (c) prior to the accumulation of 5,150 hours' time in service unless accomplished during the 1,000 hours' time in service from 4,150 hours' to 5,150 hours', and thereafter at intervals not to exceed 1,000 hours' time in service from the last inspection.

(c) Visually or by use of other FAA-approved methods, inspect the areas surrounding both left and right lower No. 4 wing plank drain holes located adjacent to Wing Station 159.6 for cracks radiating from the holes. Do not remove the 1/4-inch diameter rivets which plug and seal the holes on wet bay aircraft.

(d) If a crack is found during the inspection required by (c), the following apply:

(1) Except as provided for by (3), if the crack length does not exceed 0.60 inch measured from the center of the drain hole, before further flight make a permanent repair in accordance with section 2.B of Lockheed Service Bulletin 88/SB-587A as revised by Lockheed Service Bulletin 88/SB-587B, or an equivalent repair approved by the Chief, Aircraft Engineering Division, FAA Western Region. The aircraft may be ferried in accordance with the provisions of FAR 21.197 to the base at which the repairs are to be accomplished; and

(2) If the crack exceeds 0.60 inch measured from the center of the drain hole, before further flight make a permanent repair approved by the Chief, Aircraft Engineering Division, FAA Western Region. The aircraft may be ferried in accordance with the provisions of FAR 21.197 to the base at which the repairs are to be accomplished.

(3) If the crack length does not exceed 0.32 inch, measured from the center of the drain hole, permanent repair of the drain hole area in accordance with (d)(1) may be deferred for a period not to exceed 900 hours' time in service after inspection if the following is complied with:

(i) Before further flight, enlarge the drain hole to 0.75-inch diameter and deburr the edges.

(ii) Inspect the area surrounding the enlarged hole for cracks, by dye penetrant method or an FAA-approved equivalent, within 60 hours' time in service after compliance with (i), and thereafter at intervals not to exceed 60 hours' time in service from the last inspection for the first 450 hours' time in service and for the remaining allotted hours' time in service inspect the area surrounding the enlarged hole for cracks, by dye penetrant method or an FAA-approved equivalent, at intervals not to exceed 30 hours' time in service.

(iii) If a crack is found during the inspection required by (ii), install the permanent repair required by (d)(1) or (2), as applicable, before further flight. The airplane may be ferried in accordance with the provisions of FAR 21.197 to the base at which the repairs are to be accomplished.

(e) The periodic reinspection may be discontinued for aircraft on which the drain hole cracks are repaired in accordance with (d) and for aircraft with uncracked drain hole areas on which the repair of section 2.B. of Lockheed Service Bulletin 88/SB-587A as revised by Lockheed Service Bulletin 88/SB-587B. or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region, is incorporated as a reinforcement.

(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 Service Bulletins 88/SB-587A dated April 10, 1964, and 88/SB-587B dated August 20, 1964, cover this same subject).

This directive effective July 30, 1965.

Revised December 9, 1965.