63-26-05 VICKERS: Amdt. 657 Part 507 Federal Register December 21, 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 figures 4 and 5 of Vickers Preliminary Technical Leaflet No. 107 Issue 2 (800/810 Series). To preclude further failures accomplish the following on Nos. 1 and 4 flap units:
(a) Within 200 landings after the effective date of this AD, on aircraft which have accumulated 10,000 or less landings, unless already accomplished within the past 1,300 landings, conduct dye penetrant or FAA approved equivalent inspection for cracks in accordance with PTL 107 Issue 2. If no cracks are found, reinspect at intervals not exceeding 1,500 landings until the aircraft accumulates between 10,000 and 11,000 landings during which time the airplane must be reinspected. Thereafter, the aircraft must be reinspected at intervals not exceeding 600 landings until atotal of not more than 12,000 landings are 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 50 landings after the effective date of this AD on aircraft which have attained over 10,000 landings, unless already accomplished within the past 550 landings, conduct the inspection of (a). If no cracks are found, reinspect at intervals not exceeding 600 landings until reinforcing scheme (a)(1) or (a)(2), or FAA approved equivalent, has been incorporated. Incorporate the reinforcing scheme within 2,000 landings after the effective date of this AD.
(c) Cracked flap beams are considered acceptable for a further 500 landings provided that the cracks are within the limits specified in "Definition of Serviceability" paragraph 3 of the referenced PTL, and provided that the area is reinspected in accordance with (a) within every 100 landings to ensure that no crack propagation has occurred. Incorporate repair/reinforcing scheme (a)(1) or (a)(2), or FAA approved equivalent, as follows:
(1) Within 10 landings from the time of crack detection for aircraft with unacceptable cracks, and within 10 landings for aircraft with cracks that are found to propagate in length.
(2) On or before the completion of 500 landings 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 of this AD may be discontinued.
It will be necessary for the operator to maintain a record of landings in order to ascertain compliance with this AD. If past records are unavailable, the number of landings prior to the effective date of this AD may be estimated by substituting one landing for each hour in service prior to the effective date of this AD.
(Vickers-Armstrong PTL No. 107 Issue 2 (800/810 Series) and Modification FG.1948 cover this subject.)
This directive effective January 21, 1964.