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2001-25-08 Sikorsky Aircraft Corporation: Amendment 39-12561. Docket No. 2001-SW-18-AD.
Applicability: Model S-70A helicopters, serial numbers 700029, 701129, 701322, 701325, 701327, 701329, 701331, 701333, 701592, 701593,701594, 701595, 701613, 701614, 701825, 701835, 702127, and 702129, and Model S-70C helicopters, serial numbers 70583, 70785, 70788, 70792, 70793, 70794, 70797, 70798, 70799, 70800, 70811, 70812, 70813, 70830, 70831, 70836, 70837, 70848, 70855, 70856, 70867, 70868, 70879, 70884, 70892, 70910, 70918, 70927, 70928, 70929, 70949, 70950, 70951, 70954, 70957, 70958, 70959, 70965, 70966, and 701029, certificated in any category.
Note 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this ADis affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
Compliance: Required within 30 hours time-in-service, unless accomplished previously.
To prevent excessive torque on a jackpad mounting bolt retention nut (nut), failure of a main landing gear drag beam (beam), and subsequent loss of control of the helicopter during takeoff or landing, accomplish the following:
(a) With jackpad installed, using a 10X or higher magnifying glass, visually inspect each beam, part number (P/N) 70250-32105, for a crack at a 3.0-inch radius around the upper and lower jackpad holes.
(1) If a crack is found, remove the beam.
(2) If a crack is suspected, dye-penetrant inspect the beam, and if a crack is found, remove the beam.
Note 2: Temporary Revision No. 19 of Sikorsky Aircraft Model S-70 Maintenance Manual, dated January 23, 2001, pertains to the subject of this AD.
(b) If a crack is not found while accomplishing the requirements of paragraph (a) of this AD, retorque the nut, part number (P/N) MS21245-L12, on each beam as follows:
(1) Restrain the jackpad and rotate the nut counterclockwise to release the torque on the nut. If movement of the jackpad occurs, remove and replace the sealant from the lower surface of the jackpad/beam interface.
(2) Retorque the nut to 45-50 ft-lbs.
(3) Apply sealant to the nut and the immediate area.
(4) After sealant has dried, touch up the paint as required.
(5) After the paint has dried, apply a slippage mark (of a contrasting color) to the nut as follows:
(i) Wipe the area to be marked with a clean-lint-free cloth.
(ii) Apply F1000 Sentry Seal, or equivalent, with a width of approximately one half the diameter of the nut (to a maximum width of 3/16 inch) and extending a minimum of 1/2 inch on the base part (or to the edge of the part, whichever is smaller).
Note 3: Sikorsky Alert Service Bulletin No. 70-03-2, dated July 26, 1999, pertains to the subject of this AD.
(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Boston Aircraft Certification Office, FAA. Operators shall submit their requests through an FAA Principal Inspector, who may concur or comment and then send it to the Manager, Boston Aircraft Certification Office.
Note 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Boston Aircraft Certification Office.
(d) Special flight permits may be issued in accordance with 14 CFR 21.197 and 21.199to operate the helicopter to a location where the requirements of this AD can be accomplished.
(e) This amendment becomes effective on January 2, 2002.
