AD 84-08-01

84-08-01 SIKORSKY AIRCRAFT DIVISION: Amendment 39-4846. Applies to all Sikorsky Model S-76A helicopters, certificated in all categories, that are equipped with Part Number (P/N) 76000-05100-043, or -045 tail rotor pitch control shaft assemblies.

Compliance is required within 25 hours time in service after the effective date of this AD unless already accomplished within the last 75 hours time in service and thereafter at intervals not to exceed 100 hours time in service from the last inspection.

To prevent possible failure of the tail rotor pitch control shaft bearing assembly and subsequent partial loss of directional control of the helicopter, accomplish the following:

(a) Inspect the tail rotor pitch control shaft bearing assembly for axial movement in accordance with Paragraph E of Sikorsky Alert Service Bulletin (ASB) No. 76-66-18, as revised by ASB No. 76-66-18A, or with an equivalent procedure approved under paragraph (c) of this AD.

(b) If the control shaft assembly axial movement exceeds 0.010 inch, replace with a serviceable assembly in accordance with Paragraph E of Sikorsky ASB No. 76-66-18, as revised by ASB No. 76-66-18A, or with an equivalent procedure approved under paragraph (c) of this AD.

(c) Upon submission of substantiating data and upon request by an owner or operator through an FAA maintenance inspector, the repetitive inspection interval of this AD may be adjusted and an equivalent method of compliance with this AD may be approved by the Manager, Boston Aircraft Certification Office, 12 New England Executive Park, Burlington, Massachusetts 01803, telephone number (617) 273-7329.

(Sikorsky S-76 Maintenance Manual SA 4047-76-2-1, 5-20-00, Item No. 22, page 30A, March 12, 1984, pertains to the repetitive inspection.)

This amendment becomes effective April 24, 1984.