AD 72-11-04

final rule

Airworthiness Directives; Enstrom Model F-28A Helicopters

AD Number
72-11-04
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.
Technical illustration of a helicopter rotor hub assembly
Problem area Rotor system

Applicability

TypeManufacturerModelDetails
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.

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

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.

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

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

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

Affected Aircraft

Enstrom Model F-28A helicopters (Serial Numbers 1 through 83)

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

Federal Register Abstract

Failure Tail Rotor Drive Pins

Applicability Source Text

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AD Final Rules - DRS_72-11-04.html
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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Superseded AD: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Superseded By: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

Show stored source text (verify against official source)
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

This site is not affiliated with or endorsed by the FAA. Always verify with official sources.