65-21-05 LOCKHEED: Amdt. 39-136 Part 39 Federal Register September 11, 1965. Applies to Models 188A and 188C Series Airplanes.
Compliance required as indicated.
To Detect and repair cracks in the vertical stabilizer -to-fuselage attach channel, P/N 803179-5, located at Fuselage Station 1117.6, accomplish the following:
(a) For airplanes with 8,000 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 1,350 hours' time in service prior to the effective date of this AD, and thereafter at intervals not to exceed 1,500 hours' time in service form the last inspection.
(b) For those airplanes with less than 8,000 hours' time in service as of the effective date of this AD, comply with (c) prior to the accumulation of 8,150 hours' time in service unless accomplished during the 1,350 hours' time in service from 6,650 hours' to 8,000 hours' and thereafter at intervals not to exceed1,500 hours' time in service from the last inspection.
(c) Visually or by use of other FAA-approved methods, inspect the vertical stabilizer- to-fuselage attach channel, P/N 803179-5, located at F. S. 1117.6 for cracks. If a crack is found, confirm crack end by inspection with dye penetrant or an FAA-approved equivalent.
(d) If a crack is found during the inspection required by (c), the following apply:
(1) If the crack length does not exceed 3 inches, stop drill the crack and install angles P/N 841309-101 and P/N 841309-102 in accordance with Lockheed Drawing 841307 or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region, before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repair can be made.
(2) If the crack length exceeds 3 inches, replace the P/N 803179-5 channel with a new P/N 803179-5 channel and install angles P/N 841309-101 and P/N 841309-102 in accordance with LockheedDrawing 841307 or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region, before further flight, except that the airplane may be flown in accordance with FAR 21.197 to a base where the repair can be made.
(e) The periodic reinspection may be discontinued for airplanes on which the cracks are repaired in accordance with (d) and for airplanes with an uncracked P/N 803179-5 channel on which the P/N 841309-101 and P/N 841309-102 angles are installed in accordance with Lockheed Drawing 841307 as a reinforcement or on which an equivalent reinforcement approved by the Chief, Aircraft Engineering Division, FAA Western Region is incorporated.
(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.
This directive effective October 11, 1965.