68-03-03 LOCKHEED: Amendment 39-550. Applies to Model 382 and 382B series airplanes, Serial Numbers 3946 and 4101 through 4146.
Compliance required as indicated.
To detect and repair chordwise cracks in the wing lower surface and in the adjacent stringers at Wing Stations 181 Left and 181 Right accomplish the following:
1. For airplanes with 2,000 or more hours' time in service on the effective date of this AD, inspect in accordance with Paragraph 3., below, within the next 150 hours' time in service unless accomplished within 450 hours' time in service prior to the effective date of this AD, and thereafter at intervals not to exceed 600 hours.
2. For those airplanes with less than 2,000 hours' time in service on the effective date of this AD, inspect in accordance with Paragraph 3. prior to the accumulation of 2,150 hours' time in service and thereafter at intervals not to exceed 600 hours' time in service from the last inspection.
3. Inspect P/N 370554-3 (lowersurface panel number 1), P/N 370555-3 (lower surface panel number 2), and P/N 370556-3 (lower surface panel number 3) at Wing Stations 181 Left and 181 Right at the end fastener holes which are common to the outboard ends of the reinforcing beams running spanwise beneath P/N 370557-5 (stringer number 15), P/N 370560-7 (stringer number 16), P/N 370560-7 (stringer number 20) and P/N 370557-5 (stringer number 21). Inspect an area four inches spanwise by seven inches chordwise surrounding each fastener hole. Inspect the surface of each stringer which is adjacent to a wing lower surface panel crack over a spanwise length of two inches to each side of the wing surface crack. Inspection shall be by dye penetrant method in accordance with Lockheed Alert Service Bulletin A382-026 or later FAA approved revision, or in an equivalent manner approved by the Chief, Engineering and Manufacturing Branch, FAA, Southern Region.
4. Except as provided in subparagraphs a. and b., below, prior to further flight repair cracked skin and cracked stringers in accordance with Lockheed Service Bulletin 382-028 or later FAA approved revision, or in an equivalent manner approved by the Chief, Engineering and Manufacturing Branch, FAA, Southern Region.
a. The airplane may be flown in accordance with FAR 21.197 to a base at which the repair can be made.
b. Chordwise cracks in the inspection areas designated in Paragraph 3. are not cause for restriction on standard category operations for the conditions described in either (1) or (2), below.
(1) At Wing Stations 181 Left and 181 Right, only one lower surface panel contains a single crack which does not exceed two inches in length, and there is no crack in any stringer.
(2) At Wing Stations 181 Left and 181 Right, two or more lower surface panels contain cracks, each of which does not exceed 0.70 inch in length including fastener hole, and the sum of individual crack lengths in all panels does not exceed 3.60 inches, andthere are no cracks in any stringer. For airplanes which are operated with such surface panel cracks, inspect in accordance with Paragraph 3, at intervals not to exceed 60 hours' time in service from the last inspection.
5. The inspections required by this AD may be discontinued for those airplanes repaired or reinforced in accordance with Paragraph 4. or in accordance with an equivalent repair or reinforcement approved by the Chief, Engineering and Manufacturing Branch, FAA, Southern Region.
6. Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA, Southern 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-Georgia Alert Service Bulletin A382-026A, dated November 17, 1967, and Service Bulletin 382-028, dated October 26, 1967, cover this same subject.
This amendment becomes effective February 10, 1968.