AD 84-17-01

84-17-01 SIKORSKY AIRCRAFT: Amendment 39-4972. Applies to Model S-76A helicopters with main rotor pitch horn, P/N 76102-08011-042, installed and certificated in all categories.

Compliance is required as indicated, unless already accomplished.

For helicopters with main rotor pitch horns with more than 5,500 hours time in service on the effective date of this AD, compliance is required prior to further flight, unless already accomplished, and thereafter at intervals not to exceed 5,500 hours time in service.

For helicopters with main rotor pitch horns with 5,500 hours or less time in service on the effective date of this AD, compliance is required prior to the accumulation of 5,500 hours time in service, unless already accomplished, and thereafter at intervals not to exceed 5,500 hours time in service.

To prevent possible failure of the main rotor pitch horn, accomplish the following:

(a) Remove and replace the main rotor pitch horn, P/N 76102-08011-042, with a new or an airworthy part of the same part number, that has less than 5,500 hours time in service in accordance with Sikorsky S-76A Maintenance Manual SA4047-76-2, Section 65-12-03, dated March 1, 1984, or FAA approved equivalent.

(b) Special flight permit may be issued in accordance with FAR Sections 21.197 and 21.199 to operate a helicopter to a base for replacement of the main rotor pitch horns required by this AD.

(c) Alternate repairs, modifications, or other means of compliance to the AD which provide an equivalent level of safety may be approved by the Manager, Boston Aircraft Certification Office, FAA, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803.

This amendment becomes effective January 10, 1985, as to all persons except those persons to whom it was made immediately effective by priority letter AD 84-17-01, issued August 16, 1984, which contained this amendment.