AD 69-12-06

69-12-06 BOEING: Amdt. 39-780 applies to Boeing Model 737-100, 737-200, and 737- 200C Series Airplanes. Compliance required as indicated, unless already accomplished. To detect cracking in the lugs of the aileron tab mast fittings and flanges of the aileron tab hinge fittings of Boeing Model 737 Series airplanes, and provide for the installation of parts to correct this condition, accomplish the following, or an equivalent inspection procedure and parts installation approved by the Chief, Aircraft Engineering Division, FAA Western Region. (a) Within 25 hours' time in service after the effective date of this AD, visually inspect the aileron tab mast fittings for cracks in the lugs and for an excessive gap between the fitting lugs and the tab control rod ends in accordance with Boeing Alert Service Bulletin No. 57-1040, dated May 26, 1969, (hereinafter referred to as Boeing ASB 57-1040) or later FAA approved revisions. NOTE: Designated 737 Series aircraft listed in Group II, Boeing ASB 57-1040, delivered after April 15, 1969, have had the gaps shimmed and nuts torqued by the manufacturer and may therefore be inspected within the time intervals listed in Step (4). (1) If cracks are found, replace the mast fitting with a new part in accordance with Boeing ASB 57-1040 (or later FAA approved revision) before further flight. (2) If no cracks are found, measure gap between mast fitting lugs and tab control rod end fitting, shim, and torque nut in accordance with instructions and limits specified in Boeing ASB 57-1040, or later FAA approved revisions. (3) If gaps between the fitting lugs and the tab control rod ends exceed those limits specified in Boeing ASB No. 57-1040, or later FAA approved revision, perform either (A) or (B) as follows: (A) Shim the gaps and torque the nuts to the limits specified in the Alert Service Bulletin. (B) Repeat the visual inspection for cracks at intervals not to exceed 25 hours' time in service, per (a)(1)and (a)(2), above. (4) After the mast fittings have been properly gapped, shimmed and nuts torqued, per (a)(2) and (a)(3) above, inspect for cracks at intervals not to exceed 160 hours time in service until at least two inspections have been accomplished, or the part has accumulated an additional 280 hours' time in service, whichever occurs later, and, thereafter, at intervals not to exceed 600 hours' time in service. (5) Inspection requirements under (a) of this AD may be terminated when: (A) the magnesium mast fittings are replaced with aluminum mast fittings per Boeing ASB No. 57-1040, (FAA approved revision to be issued); and (B) the tab control rods are replaced with adjustable tab control rods, Boeing P/N 69-60081-1, installed per instructions in Boeing Service Bulletin 27- 1025, dated April 30, 1969, or later FAA approved revisions. (b) Within 160 hours' time in service after the effective date of this AD, visually inspect the aileron tab hinge fitting flanges for cracks. (1) If cracks are found, replace hinge fitting with a new Boeing P/N 6937805-6 before further flight. (2) If no cracks are found, repeat inspection for cracks at intervals not to exceed 600 hours' time in service. NOTE: Designated 737 Series Aircraft listed in Group II, Boeing ASB 57-1040, delivered after April 15, 1969, have had the inspection of (b) performed by the manufacturer and may therefore be inspected at intervals not exceeding 600 hours' time in service. (3) Inspection requirements under (b) of this AD may be terminated when magnesium tab hinge fittings are replaced with an aluminum tab hinge fitting per Boeing ASB 57-1040, (FAA approved revision to be issued). (c) 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 period of the operator if the request contains substantiating data to justify the increase for thatoperator. (d) Airplanes having cracked parts which require replacing under this AD may be flown in accordance with FAR 21.197 with the concurrence of the Chief, Aircraft Engineering Division, FAA Western Region, to a base where the replacement of parts can be accomplished. This amendment becomes effective on 18 June 1969.