AD 76-01-09

76-01-09 PILATUS AIRCRAFT LTD: Amendment 39-2490. Applies to Pilatus Model PC-6 airplanes (all variants) manufactured by Pilatus Aircraft Ltd. serial numbers 667 and subsequent and serial numbers 2001 through 2047 inclusive manufactured by Fairchild Hiller. Compliance is required as indicated. To prevent a possible fatigue failure of the elevator attachment brackets on the inboard ends of the right and left elevator surfaces, accomplish the following: (a) Within the next 25 hours' time in service after the effective date of this AD unless already accomplished within the last 25 hours' time in service and thereafter at intervals not to exceed 50 hours time in service since the last inspection, visually inspect both the left and right brackets, P/N 6300.0011.00, of the welded attachment assembly for cracks in the flanges using a glass of at least 10 power in accordance with paragraph 2.1 of Pilatus Aircraft Ltd. Service Bulletin No. 107, dated May 1971, or an FAA-approved equivalent. (b) If cracks are found, before further flight, repair in accordance with paragraph 2.1 of Pilatus Aircraft Ltd. Service Bulletin No. 107, dated May 1971, or an FAA-approved equivalent. (c) Within the next 200 hours' time in service after the effective date of this AD, install reinforcement plates, P/Ns 6002.6993.51 and 6002.6993.52, unless already accomplished, in accordance with paragraph 2.2 of Pilatus Aircraft Ltd. Service Bulletin No. 107, dated May 1971, or an FAA-approved equivalent. (d) The repetitive inspections required by paragraph (a) of this AD may be discontinued after all cracks have been repaired and reinforcement plates have been installed in accordance with paragraph (c) of the AD. (Fairchild Hiller Service Bulletin PC-6-55-3 pertains to this same subject.) This amendment becomes effective on February 6, 1976.