63-23-03 VICKERS: Amdt. 641 Part 507 Federal Register November 9, 1963. Applies to All Viscount Model 810 Series Aircraft.
Compliance required as indicated.
Fatigue failures have been reported on flap beams in the areas shown in Figure 1 of Preliminary Technical Leaflet No. 107 (800/810 Series). To preclude further failures accomplish the following on Nos. 2 and 3 flap units:
(a) Within 500 flights* after the effective date of this AD, on aircraft which have accumulated 10,000 or less flights, unless already accomplished within the past 1,000 flights, conduct dye penetrant or FAA approved equivalent inspection for cracks in accordance with PTL 107. If no cracks are found, reinspect at intervals not exceeding 1,500 flights until the aircraft accumulates between 10,000 and 11,000 flights during which time the aircraft must be reinspected. Thereafter, the aircraft must be reinspected at intervals not exceeding 600 flights until a total of not more than 12,000 flightsare accumulated, at which time either of the following or FAA approved equivalent must be incorporated.
(1) Modification FG.1946, or
(2) The repair/reinforcing scheme defined in the referenced PTL.
(b) Within 100 flights after the effective date of this AD on aircraft which have attained over 10,000 flights, unless already accomplished within the past 500 flights, conduct the inspection of paragraph (a). If no cracks are found, reinspect at intervals not exceeding 600 flights until reinforcing scheme (a)(1) or (a)(2), or FAA approved equivalent, has been incorporated. Incorporate the reinforcing scheme within 2,000 flights after the effective date of this AD.
(c) Cracked flap beams may be considered serviceable for a further 500 flights provided that the cracks are confined to one doubler plate each side of the beam only, and extend no further than the bolt hole, per Figure 1 of PTL 107, and provided that the area is reinspected in accordance with (a) within every100 flights to ensure that no crack propagation has occurred. Incorporate repair/reinforcing scheme paragraph (a)(1) or (a)(2), or FAA approved equivalent, as follows:
(1) Within 10 flights from the time of crack detection for aircraft with unacceptable cracks, and within 10 flights for aircraft with cracks that are found to propagate in length.
(2) On or before the completion of 500 flights from the time of crack detection for aircraft with acceptable cracks.
(d) After incorporating the modification of (a)(1) or (a)(2), or FAA approved equivalent, the special inspection in this AD may be discontinued.
(Vickers-Armstrongs PTL No. 107 (800/810 Series) and Modification FG. 1946 cover this subject.)
This directive effective December 11, 1963.
*This will require operators to maintain a record of flights to ascertain compliance with this AD. If past records are unavailable the number of flights prior to this AD may be estimated.