AD 82-15-02

82-15-02 HILLER AVIATION: Amendment 39-4416. Applies to Model UH-12D, UH- 12E, UH-12E4, UH-12E-L, UH-12L, UH-12L4, and military OH-23D, OH-23F and OH-23G series helicopters, certificated in all categories, through serial No. 5187.

Compliance required as indicated, unless already accomplished.

To prevent loss of power to the main and tail rotors, accomplish the following:

Within 50 hours' additional time in service after the effective date of this AD, remove the four P/N 21041 bolts and four AN 960-716L washers which attach the mercury clutch to the torsional coupling and replace with new P/N 21041 bolts and P/N 21074-3 washers in accordance with Part 2, Accomplishment Instruction, of Hiller Aviation Service Bulletin No. 21-2 dated January 20, 1982, or FAA approved equivalent. The four P/N 21041 bolts removed per this action must be considered unairworthy and marked accordingly.

NOTE: Hiller Model UH-12 series helicopters converted to turbine power by Supplemental Type Certificate (STC) SH178WE or SH177WE do not incorporate the subject parts and therefore are not affected by this AD unless restored to the original configuration.

Special flight permits may be issued in accordance with Sections 21.197 and 21.199 of the FAR to operate rotorcraft 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, Western Aircraft Certification Field Office, FAA Northwest Mountain Region.

This amendment supersedes AD 82-10-06. This amendment becomes effective July 16, 1982.