68-07-01 GENERAL DYNAMICS: Amendment 39-568. Applies to Models 340, 440 and C-131E airplanes including those using turbo propeller power.
Compliance required as indicated.
Due to numerous reports of cracks developing in the Pilot and Copilot Direct Vision Window Frame Casting, PNs 340-3110314-9, -10, -13 and -14 (hereinafter referred to as the Casting) which affects the structural integrity of the Casting and which, in some cases, has caused loss of cabin pressurization, accomplish the following:
(a) Inspect each Casting with 4500 or more hours' time in service on the effective date of this AD for cracks in accordance with Paragraph (c) within the next 250 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 250 hours' time in service from the last inspection.
(b) Inspect each Casting with less than 4500 hours' time in service on the effective date of this AD for cracks in accordance with Paragraph (c) prior to the accumulation of 4750 hours' time in service and thereafter at intervals not to exceed 250 hours' time in service from the last inspection.
(c) Inspect all visible areas of the main body of each Casting for cracks by means of either a visual inspection with the aid of an eight power glass, a dye penetrant inspection method, an eddy current inspection method, or by a method approved by the Chief, Aircraft Engineering Division, FAA Western Region.
NOTE: In performing the inspection specified in Paragraph (c), special attention should be given to the lower left and right hand corner of the Casting.
NOTE: For purposes of complying with this AD, the main body of the Casting includes only that part of the Casting which outlines the Direct View Window and does not include the attach flanges.
(d) If a crack or cracks are found in a Casting comply with subparagraphs (1) and (2) of this Paragraph as appropriate:
(1) If the cracked Casting is completely severed at any point, replace the affected Casting with a new part, P/N 340-3110314-9 or -13 (left hand side) or P/N 340- 3110314-10 or -14 (right hand side), prior to further flight after discovery of the crack (except that the airplane may be flown at a cabin pressure differential of zero p.s.i. in accordance with FAR 21.197 to a base where the replacement can be accomplished); and
(2) If the cracked Casting is not completely severed at any point replace the affected Casting with a new part, P/N 340-3110314-9 or -13 (left hand side) or P/N 340- 3110314-10 or -14 (right hand side) within 250 hours' time in service after discovery of the initial crack except that until such time as the affected Casting is replaced in accordance with this Subparagraph:
(i) The affected airplane must be operated at a cabin pressure differential of zero p.s.i.; and
(ii) Prior to the initial takeoff after discovery of the initial crack, an operating limitation in the form of a placard must be installed inthe affected airplane in clear view of the pilot stating: "Operation Limitation. Pressurized Flight Prohibited."
(e) Operators who have not kept records of hours' time in service of individual Castings shall substitute hours' time in service of the airplane in lieu thereof.
(f) Upon request of the operator, an FAA Maintenance Inspector, subject to prior approval of the Regional Director, FAA Western Region, may adjust the compliance times herein if the request contains substantiating data to justify the increase for that operator.
This amendment becomes effective on April 29, 1968.