AD 74-17-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Enstrom Helicopter Corporation, The | F-28A | Airworthiness Directives; Enstrom Model F- 28A Helicopters |
Unsafe Condition
The main rotor gear box may experience gear tooth failure due to insufficient lubrication or material fatigue, leading to potential rotor system failure.
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Required Actions
Inspect the main rotor gearboxes by teardown and inspection at the Enstrom facility within specified timeframes based on their total time since remanufacture. Gearboxes with 100 hours or more must be inspected within 5 hours; those with less than 100 hours must be inspected before accumulating 100 hours.
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Compliance Time
within the next 5 hours
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Federal Register Abstract
Main Rotor Gear Box
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_74-17-07.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 74-17-07 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Enstrom Model F- 28A Helicopters Subject: Main Rotor Gear Box Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 08/24/1974 Make: Enstrom Helicopter Corporation, The Model: F-28A Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 74-17-07 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1925 AD NUMBER: 74-17-07 SUBJECT HEADING: Airworthiness Directives; Enstrom Model F- 28A Helicopters ACTION: SUMMARY: DATES: Effective August 24, 1974. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 74-17-07 ENSTROM: Amendment 39-1925. Applies to the following Enstrom Model F- 28A main rotor gearboxes, Serial Numbers: 03A, 016, 025, 041, 050, 063, 073, 082, 09-02-69, 08-001-72, and 20-001-72. Compliance required as indicated unless already accomplished: (a) All main rotor gearboxes in this group with a total time since remanufacture of 100 hours or more must be returned to the Enstrom facility for teardown and inspection within the next 5 hours. (b) All main rotor gearboxes in this group with a total time since remanufacture of less than 100 hours should be returned to the Enstrom facility for teardown and inspection before accumulating 100 hours. This amendment becomes effective August 24, 1974. FOOTER:
Document Text
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AD Final Rules - DRS_74-17-07.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 74-17-07 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Enstrom Model F- 28A Helicopters Subject: Main Rotor Gear Box Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 08/24/1974 Make: Enstrom Helicopter Corporation, The Model: F-28A 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: 74-17-07 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1925 AD NUMBER: 74-17-07 SUBJECT HEADING: Airworthiness Directives; Enstrom Model F- 28A Helicopters ACTION: SUMMARY: DATES: Effective August 24, 1974. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 74-17-07 ENSTROM: Amendment 39-1925. Applies to the following Enstrom Model F- 28A main rotor gearboxes, Serial Numbers: 03A, 016, 025, 041, 050, 063, 073, 082, 09-02-69, 08-001-72, and 20-001-72. Compliance required as indicated unless already accomplished: (a) All main rotor gearboxes in this group with a total time since remanufacture of 100 hours or more must be returned to the Enstrom facility for teardown and inspection within the next 5 hours. (b) All main rotor gearboxes in this group with a total time since remanufacture of less than 100 hours should be returned to the Enstrom facility for teardown and inspection before accumulating 100 hours. This amendment becomes effective August 24, 1974. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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