64-02-06 R1 SIKORSKY AIRCRAFT: Amendment 674 as amended by Amendment 39-6090.
Applies to all Sikorsky Model S-58 series helicopters.
Compliance is required as indicated unless already accomplished.
Fatigue cracks have been found in the area of the rear three bolt holes of upper pylon folding hinge fitting P/N S1620-63130-2, the forward bolt holes of mating fitting P/N S1620-64127, the forward bolt hole of the lower pylon hinge fitting P/N S1620-64131, and the lug through which the hinge bolt passes of fittings P/N's S1620-64127 and S1620-64127-7. In order to preclude propagation of fatigue cracks in these areas and subsequent serious weakening of the pylon attachment, accomplish the following:
(a) As of the effective date of this AD, conduct daily visual inspections of the area around the fitting bolt holes of all pylon and tail cone folding hinge fittings for cracks. Replace any cracked fittings before further flight.
(b) Unless already accomplished, accomplish the following in accordance with Sikorsky Service Bulletin No. 58B20-11A within 100 hours' time in service after the effective date of this AD on all upper pylon hinge fittings P/N S1620-64127 with 1,900 hours' or more time in service, or prior to the accumulation of 2,000 hours' time in service on all fittings having less than 1,900 hours' time in service as of the effective date of this AD:
(1) Remove all bushings from the hinges.
(2) Rework and inspect the bore of each hole.
(3) Install oversized replacement bushings P/N S1620-63129-7.
(c) Upon request, an alternate means of compliance which provides an equivalent level of safety with the requirements of this AD may be used when approved by the Manager, Rotorcraft Standards Staff, Rotorcraft Directorate, Aircraft Certification Service, ASW-110, FAA, Fort Worth, Texas 76193-0110.
(d) In accordance with Sections 21.197 and 21.199, the helicopter may be flown to a base where compliance may be accomplished.
Airworthiness Directive 63-09-02 was superseded by AD 64-02-06 (Amendment 674; 29 FR 559; January 21, 1964) which was effective January 31, 1964.
This amendment (39-6090, AD 64-02-06 R1) revises AD 64-02-06 and becomes effective December 27, 1988.