AD 72-11-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Enstrom Helicopter Corporation, The | F-28A | Airworthiness Directives; Enstrom Model F-28A Helicopters |
Unsafe Condition
Failure of tail rotor drive taper pins with subsequent loss of directional control.
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Required Actions
Visually inspect the 2 forward and 3 aft AN386 taper pins for looseness within 10 hours' time in service after the effective date. Replace all loose taper pins with AN386-2-8A taper pins from Enstrom or approved sources. Replace all AN386 taper pins with AN386-2-8A pins within 25 hours' time in service after the effective date.
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Compliance Time
within 10 hours' time in service after the effective date of this AD and within 25 hours' time in service after the effective date of this AD
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Affected Aircraft
Enstrom Model F-28A helicopters (Serial Numbers 1 through 83)
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Federal Register Abstract
Failure Tail Rotor Drive Pins
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_72-11-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 72-11-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Enstrom Model F-28A Helicopters Subject: Failure Tail Rotor Drive Pins Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 06/01/1972 Make: Enstrom Helicopter Corporation, The Model: F-28A Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 72-11-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1452 AD NUMBER: 72-11-04 SUBJECT HEADING: Airworthiness Directives; Enstrom Model F-28A Helicopters ACTION: SUMMARY: DATES: Effective June 1, 1972. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 72-11-04 ENSTROM: Amdt. 39-1452. Applies to Model F-28A (Serial Numbers 1 through 83) helicopters. Compliance: Required as indicated, unless already accomplished. To prevent failure of tail rotor drive taper pins with subsequent loss of directional control, accomplish the following: A) Unless Paragraph B has been accomplished, within 10 hours' time in service after the effective date of this AD visually inspect the 2 forward and 3 aft AN386 taper pins installed in the tail rotor drive shaft assembly for looseness. Prior to further flight replace all loose taper pins with AN386-2-8A taper pins acquired from either the Enstrom Factory Customer Service Department, or Enstrom Dealers in accordance with Enstrom Service Note No. 0011 dated March 29, 1972, or by any equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, Great Lakes Region. NOTE: Loose pins can be detected by: 1. Wiggling the pin with the fingers. 2. Grasping the tail rotor drive shaft with the hand and rotating the shaft back and forth while observing the movement of the pin in the mating hole. 3. Examining for loss of paint on the pin at the edge of the mating hole. 4. Examining for formation of a burr at the edge of the hole. B) Within 25 hours' time in service after the effective date of this AD, replace all AN386 taper pins installed in the tail rotor drive shaft assembly with AN386-2-8A taper pins acquired from either the Enstrom Factory Customer Service Department, or Enstrom Dealers in accordance with Enstrom Service Note No. 0011 dated March 29, 1972, or by any equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, Great Lakes Region. This amendment becomes effective June 1, 1972. FOOTER:
Document Text
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AD Final Rules - DRS_72-11-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 72-11-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Enstrom Model F-28A Helicopters Subject: Failure Tail Rotor Drive Pins Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 06/01/1972 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: 72-11-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1452 AD NUMBER: 72-11-04 SUBJECT HEADING: Airworthiness Directives; Enstrom Model F-28A Helicopters ACTION: SUMMARY: DATES: Effective June 1, 1972. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 72-11-04 ENSTROM: Amdt. 39-1452. Applies to Model F-28A (Serial Numbers 1 through 83) helicopters. Compliance: Required as indicated, unless already accomplished. To prevent failure of tail rotor drive taper pins with subsequent loss of directional control, accomplish the following: A) Unless Paragraph B has been accomplished, within 10 hours' time in service after the effective date of this AD visually inspect the 2 forward and 3 aft AN386 taper pins installed in the tail rotor drive shaft assembly for looseness. Prior to further flight replace all loose taper pins with AN386-2-8A taper pins acquired from either the Enstrom Factory Customer Service Department, or Enstrom Dealers in accordance with Enstrom Service Note No. 0011 dated March 29, 1972, or by any equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, Great Lakes Region. NOTE: Loose pins can be detected by: 1. Wiggling the pin with the fingers. 2. Grasping the tail rotor drive shaft with the hand and rotating the shaft back and forth while observing the movement of the pin in the mating hole. 3. Examining for loss of paint on the pin at the edge of the mating hole. 4. Examining for formation of a burr at the edge of the hole. B) Within 25 hours' time in service after the effective date of this AD, replace all AN386 taper pins installed in the tail rotor drive shaft assembly with AN386-2-8A taper pins acquired from either the Enstrom Factory Customer Service Department, or Enstrom Dealers in accordance with Enstrom Service Note No. 0011 dated March 29, 1972, or by any equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, Great Lakes Region. This amendment becomes effective June 1, 1972. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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