81-05-52 R1 ROBINSON HELICOPTER: Amendment 39-4082. Applies to Model R-22 Helicopters, certified in all categories, Serial Numbers 0002 through 0036, 0038 through 0061, 0064 through 0089, 0093 and 0095.
Compliance required as indicated, unless already accomplished.
To prevent coupling failure which would result in the loss of power to the main rotor accomplish the following:
(a) Prior to further flight, after receipt of telegraphic AD T81-05-52 or the effective date of this AD, whichever comes first, conduct an inspection of the main gearbox input flex coupling yoke P/N A 194 on all R-22 helicopters, Serial Nos. 0002 through 0036, 0038 through 0061, 0064 through 0089, 0093 and 0095, in accordance with Robinson Helicopter Company Service Bulletin SB-9, dated March 4, 1981, unless previously accomplished in accordance with Robinson Helicopter Company SB-6 dated January 26, 1981, within the previous ten (10) hours time in service.
(b) Replace defective main gearbox flex coupling yoke P/N A 194 with like serviceable couplings from any production lot 18 and subsequent or new inertia welded coupling P/N A 908-1. Replacement using either of these couplings is terminating action for this AD.
(c) After the inspection in (a), at intervals not to exceed ten (10) hours additional time in service, inspect Robinson R-22 Model Helicopters Serial No. 0002 through 0036, 0038 through 0061, 0064 through 0089, 0093 and 0095 main gearbox input flex coupling yoke, P/N A 194, for cracks, in accordance with Robinson Helicopter Company Service Bulletin SB-9, dated March 4, 1981. Comply with (b) if cracks are found.
(d) Do not install a yoke, P/N A 194, from production lot prior to 18 as a replacement part or as original installation.
Special flight permits may be issued in accordance with FAR 21.197 and FAR 21.199 to operate helicopters to a base for the accomplishment of inspections or modifications required by this AD.
Alternative inspections, modifications or other actions which provide an equivalent level of safety may be used when approved by the Chief, Engineering and Manufacturing Branch, FAA Western Region.
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. 553(a)(1). All persons affected by this directive, who have not already received these documents from the manufacturer, may obtain copies upon request to Robinson Helicopter Company, 24747 Crenshaw Boulevard, Torrance, California 90505. These documents may also be examined at FAA Western Region Office, 15000 Aviation Boulevard, Hawthorne, California 90261 and at FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. 20591. A historical file on this AD, which includes the incorporated material in full, is maintained by the FAA at its headquarters in Washington, D.C. and at FAA Western Region Office.
This supersedes AD No. T81-03-52.This amendment 39-4082 becomes effective April 13, 1981 to all persons except those to whom it was made immediately effective by telegraphic AD T81-05-52, dated March 4, 1981.