61-08-03 VICKERS: Amdt. 274 Part 507 Federal Register April 8, 1961. Applies to Viscount Models 744 and 745D Series Airplanes.
Compliance required as indicated, unless already accomplished.
As a result of reported failures of the bolt, P/N 80216-627, forming the forward attachment of the outboard diagonal strut on the inboard engine nacelle structure the following must be accomplished on the structure of both inboard engine nacelles.
(a) Bolts P/N 80216-627 or bolts P/N 70116-9*, as applicable, having 4,000 or more hours' time in service must be removed not later than the next 600 landings and inspected for cracks by magnetic particle inspection or FAA approved equivalent method. Particular attention should be given to the area at the junction of the head and shank and also to the thread undercut.
(b) Bolts found cracked must be replaced prior to further flight.
(c) Compliance with "The Action" paragraphs of British Aircraft Corporation (Operating) Limited, Preliminary Technical Leaflet (PTL 228), Issue 2 (700 Series) is required when accomplishing the inspection of paragraph (a).
(d) After compliance with (a), (b), and (c) no further inspection is necessary.
(e) For the purpose of complying with this AD, subject to acceptance by the assigned FAA maintenance inspector, the number of landings may be determined by dividing each aircraft's hours' time in service by the operator's fleet average time from takeoff to landing for the aircraft type. Model 745D operators who have kept a record of flights prior to the effective date of this AD may account for them in complying with this AD by counting each flight as one landing.
(British Aircraft Corporation (Operating) Limited, PTL No.228, Issue 2, (700 Series) covers this subject.
This directive effective May 9, 1961.
Revised September 28, 1965.
*Bolts P/N 80216-627 were incorporated by Mod. 1306 and on later production aircraft.
Pre-mod. standard bolts P/N70116-9 are identical except 1/32-inch less in diameter.