61-24-04: Horizontal Stabilizer Rear Spar

61-24-04 LOCKHEED: Amdt. 367 Part 507 Federal Register November 14, 1961. Applies to All Models 049, 149, 649, 749, and 1049 Series Aircraft Having 25,000 Or More Hours' Time In Service. Compliance required as indicated. As a result of reports of numerous cases of cracking in the horizontal stabilizer rear spar- to-fuselage attachment, the following inspections must be accomplished within the next 400 hours' time in service after effective date of this AD, unless already accomplished within the last 4,300 hours' time in service and at intervals of 4,700 hours' time in service. Inspect the rear spar web (P/N 271488-4) for cracks in the 0.38 inch radius adjacent to the stabilizer-to-fuselage fitting on both the left and right sides of the airplane. If cracks are found, they must be repaired prior to further flight in accordance with Lockheed Service Letter FS/250615, or FAA approved equivalent. The above inspection may be discontinued upon incorporation of the repair or reinforcement provisions of the Lockheed Service Letter, or FAA approved equivalent. Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, 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 December 14, 1961.