AD 81-17-03

final rule

Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters

AD Number
81-17-03
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft Hiller Aviation | Siam Hiller Holdings, Inc. UH-12 Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters
aircraft Hiller Aviation | Siam Hiller Holdings, Inc. UH-12A Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters
aircraft Hiller Aviation | Siam Hiller Holdings, Inc. UH-12B Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters
aircraft Hiller Aviation | Siam Hiller Holdings, Inc. UH-12C Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters
aircraft Hiller Aviation | Siam Hiller Holdings, Inc. UH-12D Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters
aircraft Hiller Aviation | Siam Hiller Holdings, Inc. UH-12L Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters
aircraft Hiller Aviation | Siam Hiller Holdings, Inc. UH-12L4 Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters
aircraft Hiller Aviation | Siam Hiller Holdings, Inc. UH-12E Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters
aircraft Hiller Aviation | Siam Hiller Holdings, Inc. UH-12E-L Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters

Unsafe Condition

Failure of the main transmission due to magnetic chips or gold colored flecks in the oil filter and chip detector.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Inspect the main transmission oil filter and chip detector per Hiller Service Notice No. 23-2. If chips or gold flecks are found, open transmission, inspect planetary system, replace worn parts, clean filter, replace parts, and logbook entry. Inspect every 25 or 50 hours depending on engine type. Replace P/N 23586-3 spacers within 1200 hours or next 100 hours.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Within 25 hours' additional time in service from the effective date of this AD for initial inspection. Subsequent inspections every 25 hours' time in service for turboshaft and 50 hours for reciprocating engine aircraft. Replace spacers prior to 1200 hours' time in service or within the next 100 hours after the effective date.

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Hiller Aircraft Model UH-12 all series helicopters with Main Transmission P/Ns 23500-3 and 23700-3, -5, -7 or -9, including Soloy Conversions STCs SH177WE and SH178WE.

AI-generated summary from the source AD text. Verify against the official source before acting.

Federal Register Abstract

Main Transmission

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_81-17-03.html
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AD Number:
81-17-03
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters
Subject:
Main Transmission
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
08/24/1981
Make:
Hiller Aviation | Siam Hiller Holdings, Inc.
Model:
UH-12 | UH-12A | UH-12B | UH-12C | UH-12D | UH-12L | UH-12L4 | UH-12E | UH-12E-L
Product Type:
Aircraft
Product Subtype:
Rotorcraft
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 81-17-03
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-4187

AD NUMBER:   81-17-03

SUBJECT HEADING:   Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective August 24, 1981.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
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 and make 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, Engineering and 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.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_81-17-03.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
81-17-03
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters
Subject:
Main Transmission
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
08/24/1981
Make:
Hiller Aviation | Siam Hiller Holdings, Inc.
Model:
UH-12 | UH-12A | UH-12B | UH-12C | UH-12D | UH-12L | UH-12L4 | UH-12E | UH-12E-L
Product Type:
Aircraft
Product Subtype:
Rotorcraft
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 81-17-03
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-4187

AD NUMBER:   81-17-03

SUBJECT HEADING:   Airworthiness Directives; HILLER AIRCRAFT Model UH-12 Series Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective August 24, 1981.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
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 and make 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, Engineering and 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.

FOOTER:

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Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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