AD 82-13-04 R1

82-13-04 R1 HILLER AVIATION: Amendment 39-4400 as amended by Amendment 39- 4454. Applies to Model UH-12E and UH-12L series helicopters certificated in all categories (including military Models OH-23F and OH-23G) equipped with torsional couplings P/N 21047- 9 and -11 serial numbers 497 through 766.

Compliance required within the next 50 hours' time in service after the effective date of this AD or within 300 hours' time in service since September 8, 1980, whichever occurs earlier, unless already accomplished, and thereafter at intervals not to exceed 300 hours' time in service since the last inspection.

To prevent possible loss of driving torque to the helicopter rotor system, accomplish this following:

(a) Inspect the P/N 21047-9 and 21047-11 torsional couplings as specified in paragraph 2 of Hiller Aviation Service Bulletin UH-12-21-1, Revision 2, dated April 2, 1982 (after this referred to as SB UH-12-21-1), or FAA approved equivalent.

(b) If torsional coupling is found to be serviceable, reinstall per paragraph 2 of SB UH-12-21-1 or FAA approved equivalent and revert to the repetitive inspection schedule of this AD.

(c) If torsional coupling installation does not meet the inspection requirements of paragraph (a) of this AD, replace with like serviceable part(s) and revert to the repetitive inspection schedule of this AD.

(d) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate helicopters to a base for the accomplishment of inspections required by this AD.

(e) 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.

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

This supersedes Amendment 39-3907 (45 FR 59138), AD 80-18-13. Amendment 39-4400 became effective July 1, 1982. This amendment 39-4454 becomes effective September 13, 1982.