AD 64-11-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Siam Hiller Holdings, Inc. | UH-12E | Airworthiness Directives; Hiller Model UH-12E Helicopters |
| aircraft | Siam Hiller Holdings, Inc. | UH-12E-L | Airworthiness Directives; Hiller Model UH-12E Helicopters |
Unsafe Condition
Failures of the tail rotor pinion gear have been experienced with several different gear heat treat lots and on helicopters both with and without rotor brakes installed.
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Required Actions
Replace tail rotor pinion gears identified as Hiller P/N 23522 or P/N 23634 with P/N 23634-3. Gears with less than 50 hours total time by May 16, 1964 must be replaced before 100 hours time in service. Gears with 50+ hours must be replaced within next 50 hours time in service.
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Compliance Time
Prior to the accumulation of 100 hours' total time in service
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Federal Register Abstract
Tail Rotor Pinion Gears
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_64-11-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 64-11-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Model UH-12E Helicopters Subject: Tail Rotor Pinion Gears Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 05/16/1964 Make: Siam Hiller Holdings, Inc. Model: UH-12E | UH-12E-L Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 64-11-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 64-11-02 SUBJECT HEADING: Airworthiness Directives; Hiller Model UH-12E Helicopters ACTION: SUMMARY: DATES: Effective May 16, 1964. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 64-11-02 HILLER: Amdt. 730 Part 507 Federal Register May 16, 1964. Applies to All Model UH-12E Helicopters. Compliance required as indicated. A number of failures of the tail rotor pinion gear have been experienced. These failures have been experienced with several different gear heat treat lots and on helicopters both with and without rotor brakes installed. To preclude any additional failures, accomplish the following: (a) Replace tail rotor pinion gears identified as Hiller P/N 23522 or P/N 23634 with a tail rotor pinion gear P/N 23634-3 as follows: (1) Gears with less than 50 hours total time in service on the effective date of this AD shall be replaced prior to the accumulation of 100 hours' total time in service. (2) Gears with 50 hours or more total time in service on the effective date of this AD shall be replaced within the next 50 hours' time in service. (b) Tail rotor pinion gears identified as P/N 23634-3 are satisfactory for unlimited service life. NOTE: An "-A" following P/N 23634 should be disregarded inasmuch as this is a gear vendor's marking and not part of the Hiller part number. (Hiller Service Information Letter No. 3036 "C" covers this same subject.) This supersedes AD 63-26-02. This directive effective May 16, 1964. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_64-11-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 64-11-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Model UH-12E Helicopters Subject: Tail Rotor Pinion Gears Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 05/16/1964 Make: Siam Hiller Holdings, Inc. Model: 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: 64-11-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 64-11-02 SUBJECT HEADING: Airworthiness Directives; Hiller Model UH-12E Helicopters ACTION: SUMMARY: DATES: Effective May 16, 1964. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 64-11-02 HILLER: Amdt. 730 Part 507 Federal Register May 16, 1964. Applies to All Model UH-12E Helicopters. Compliance required as indicated. A number of failures of the tail rotor pinion gear have been experienced. These failures have been experienced with several different gear heat treat lots and on helicopters both with and without rotor brakes installed. To preclude any additional failures, accomplish the following: (a) Replace tail rotor pinion gears identified as Hiller P/N 23522 or P/N 23634 with a tail rotor pinion gear P/N 23634-3 as follows: (1) Gears with less than 50 hours total time in service on the effective date of this AD shall be replaced prior to the accumulation of 100 hours' total time in service. (2) Gears with 50 hours or more total time in service on the effective date of this AD shall be replaced within the next 50 hours' time in service. (b) Tail rotor pinion gears identified as P/N 23634-3 are satisfactory for unlimited service life. NOTE: An "-A" following P/N 23634 should be disregarded inasmuch as this is a gear vendor's marking and not part of the Hiller part number. (Hiller Service Information Letter No. 3036 "C" covers this same subject.) This supersedes AD 63-26-02. This directive effective May 16, 1964. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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