80-22-55 R4 SIKORSKY AIRCRAFT: Amendment 39-4018 as amended by Amendment 39-4043 is further amended by Amendment 39-4336. Applies to S-76A series helicopters certificated in all categories.
To prevent operation with cracked or separated main rotor damper piston rods accomplish the following:
1. Within 25 hours time in service, after the effective date of this AD, and thereafter at intervals not to exceed 30 hours time in service, conduct dye penetrant inspections for cracks in the piston rods of P/N 76106-08000-042 and -043 main rotor dampers with more than 400 hours time in service or that have had a damper spherical bearing replaced. Accomplish these inspections in accordance with specification MIL-I-6866, Type II, Method C, and with at least a 3-power magnifying glass. Protect piston seals and rod end bearings from cleaning and inspection fluids. If a crack is found, replace the piston rod prior to further flight with a serviceable piston rod.
2. On sphericalbearings of P/N 76106-08000-042 and -043 main rotor dampers with more than 100 hours time in service:
Within the next 25 hours time in service, after the effective date of this AD, and thereafter at intervals not to exceed 15 hours time in service, conduct a bearing wear inspection of the spherical bearings of P/N 76106-08000-042 and -043 main rotor dampers in accordance with Item 88 of Temporary Revision 5-27 (reference Paragraph 9 of Temporary Revision 5-23) of Sikorsky S-76 Maintenance Manual No. SA4047-76-2.
When a damper spherical bearing fails to meet the wear criteria of this inspection, conduct a dye penetrant inspection in accordance with the specification in paragraph 1 of the damper piston rod for cracks. If a crack is found, replace the piston rod prior to further flight with a serviceable piston rod.
Note: Mandatory requirements for wear inspections of the spherical bearings of P/N 76106-08000-044 dampers are contained in Airworthiness Limitations Section, Chapter 4, Sikorsky S-76A Maintenance Manual, 5A 4047-76-2-1.
3. Other methods of compliance with this directive must be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, New England-Region, 12 New England Executive Park, Burlington, Massachusetts 01803.
NOTE: The following revisions to the Sikorsky S-76 Maintenance Manual No. 5A 4047-76-2 pertain to the subject matter of this directive.
a. Item 28 of Temporary Revision No. 5-21, dated January 28, 1981.
b. Item 88 of Temporary Revision No. 5-27, dated January 28, 1981 (reference Paragraph 9 of Temporary Revision 5-23).
c. Temporary Revision No. 5-31, dated January 28, 1981.
The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive, who have not already received these documents from the manufacturer, may obtain copies upon request to Sikorsky Aircraft, Division of United Technologies Corporation, Stratford, Connecticut 06602.
These documents may also be examined at FAA, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, and at FAA Headquarters, 800 Independence Avenue, S.in., Washington, D.C.
A historical file on this AD is maintained by the FAA at its Headquarters in Washington, D.C., and at the FAA, New England Region Headquarters, Burlington, Massachusetts.
Amendment 39-4018 became effective upon publication in the FEDERAL REGISTER for all persons except those to whom it was made effective immediately by telegram dated October 24, 1980, and air mail letter dated November 21, 1980.
Amendment 39-4043 became effective February 15, 1981.
This amendment 39-4336 becomes effective March 10, 1982.