AD 79-03-07

79-03-07 HILLER AVIATION: Amendment 39-3409. Applies to Model UH-12D and UH-12E helicopters which have been converted to turbine power in accordance with Soloy Conversions, Limited, STC Nos. SH177WE and SH178WE respectively, certificated in all categories. Compliance required as indicated unless already accomplished.

To reduce the hazard to aircraft and ground personnel as a result of repeated execution of emergency procedures involving unnecessary external load deployment and full autorotation following false low rotor speed warning system activation, accomplish the following:

A. Within the next 200-hours time in-service, or 1 month calendar time, whichever occurs first after the effective date of this AD, replace Globe Industries' P/N 22A571 or P/N 22A580 main rotor tachometer generator with Globe Industries' P/N 22A623 main rotor tachometer generator in accordance with Soloy Conversions, Limited Service Bulletin 03-560 dated March 31, 1978, or later FAA approved revisions. Silicone sealing procedures required for installation of this new style generator are described in this bulletin.

B. Equivalent methods of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest 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. 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 Soloy Conversions, Limited, Post Office Box 60, Chehalis, Washington 98532. These documents may also be examined at FAA Northwest Region, 9010 E. Marginal Way South, Seattle, Washington 98108.

This amendment becomes effective February 21, 1979.