79-20-02 FOKKER-VFW: Amendment 39-3571. Applies to Model F-27 Mark 100, 200, 300, 400, 500, 600, 700 airplanes, certificated in all categories, all aircraft serial numbers up to and including 10569 which have Dowty Rotol nose landing gear assembly other than type 200565001, 200568001, or 200678001 installed, except aircraft serial numbers 10549, 10561, 10562, and 10563.
Compliance is required as indicated, unless already accomplished.
To prevent fatigue failure of improperly machined nose wheel axles, accomplish the following:
(a) Within the next 500 hours time in service after the effective date of this AD or at the next nose wheel change, whichever occurs first, inspect the bore of the nose wheel axle (Dowty Rotol P/N 9009Y12) in accordance with Section 2, "Accomplishment Instructions", of Fokker Service Bulletin No. F27/32-129 dated May 1, 1978, and Section 2, "Accomplishment Instructions" of Dowty Rotol Service Bulletin No. 32-100B, dated April 25, 1978 or DowtyRotol Service Bulletin No. 32-30S, dated April 25, 1978, as appropriate, (hereinafter referred to as the Dowty Rotol Service Bulletin) or an FAA-approved equivalent, and -
(1) If no undercut is found and the change in section from the central bore to the threaded bore is a 0.25 inch maximum radius or a 20 degree tapered chamfer, identify the axle in accordance with item 2.B.(1) of the Dowty Rotol Service Bulletin, or an FAA-approved equivalent, and return the axle to service.
(2) If an undercut is found and both ends have a smooth transition to the adjacent area and provided the axle wall thickness is 0.115 inches or more, identify the axles in accordance with paragraph item 2.B.(1) of the Dowty Rotol Service Bulletin, or an FAA- approved equivalent, and return the axle to service.
(3) If an undercut is found and the axle wall thickness is less than 0.115 inches, or if either or both ends of the undercut do not have a smooth transition to the adjacent area, remove theaxle from service and replace with an axle which is identified in accordance with paragraph (a)(1) or (a)(2) of this AD.
(b) Before releasing to service any nose wheel axles (Dowty Rotol P/N 9009Y12) held as spares, inspect each nose wheel axle and if it is not already identified in accordance with paragraph 2.B.(1) of the Dowty Rotol Service Bulletin or an FAA-approved equivalent, inspect the axle, and identify it or remove it from service in accordance with paragraph (a) of this AD.
(c) Before releasing to service any spare nose wheel landing gears assemblies other than type 200565001, 200568001, or 200678001, inspect the nose axle (Dowty Rotol P/N 9009Y12) installed in such nose wheel landing gear assembly and if it is not already identified in accordance with paragraph 2.B.(1) of the Dowty Rotol Service Bulletin or an FAA-approved equivalent, inspect the axle, and identify it or remove it from service and replace it in accordance with paragraph (a) of this AD.
(d) For the purposes of this AD, an FAA equivalent must be approved by the Chief, Aircraft Certification Staff, AEU-100, FAA, Europe, Africa and Middle East Region, c/o American Embassy, Brussels, Belgium.
NOTE: Dowty Rotol Service Bulletin 32-30S is identical to Dowty Rotol Service Bulletin No. 32-100B but applies only to Fokker Model F-27 Mk 500.
This amendment becomes effective October 19, 1979.