AD 81-17-03

81-17-03 HILLER AIRCRAFT: Amendment 39-4187. Applies to Model UH-12 all series helicopters, certified in all categories, including Soloy Conversions STCs SH177WE and SH178WE, equipped with Main Transmission P/Ns 23500-3 and 23700-3, -5, -7 or -9.

Compliance required as indicated, unless already accomplished.

To prevent failure of the main transmission, accomplish the following:

(a) Within 25 hours' additional time in service from the effective date of this AD, inspect the main transmission oil filter and chip detector according to paragraph 2 of Hiller Service Notice No. 23-2, dated 28 July 1981.

(1) If magnetic chips or a quantity of gold colored flecks are present in the filter bowl, open transmission, inspect planetary system and replace worn parts per Hiller Overhaul Manual, before further flight.

(2) If no chips are present on the magnetic chip detector, and only a trace of gold flecks is found in the filter bowl, clean filter and bowl, replace andmake detailed log book entry of the condition. If gold flecks are found after an additional 25 hours' time in service during an inspection per (a) above, replace with like serviceable part(s) per (a)(1), above, before further flight.

(b) After completion of (a) (1) or (2) above, inspect, every 25 hours' time in service for turboshaft powered aircraft and 50 hours' time in service for reciprocating engine powered aircraft, according to (a) above.

(c) Prior to 1200 hours' time in service or within the next 100 hours, after the effective date of this AD, remove P/N 23586-3 spacers from service and replace with serviceable parts.

(d) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate aircraft to a base for the accomplishment of inspections or modifications 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, Engineeringand Manufacturing Branch, FAA Western Region.

The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made apart 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 Hiller Aviation, 2075 W. Scranton Avenue, Porterville, California 93257. 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 amendment becomes effective August 24, 1981.