AD 77-20-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Enstrom Helicopter Corporation, The | 280 | Airworthiness Directives; Enstrom Model F28, F28A, F28C, 280 and 280C Helicopters |
| aircraft | Enstrom Helicopter Corporation, The | 280C | Airworthiness Directives; Enstrom Model F28, F28A, F28C, 280 and 280C Helicopters |
| aircraft | Enstrom Helicopter Corporation, The | F-28 | Airworthiness Directives; Enstrom Model F28, F28A, F28C, 280 and 280C Helicopters |
| aircraft | Enstrom Helicopter Corporation, The | F-28A | Airworthiness Directives; Enstrom Model F28, F28A, F28C, 280 and 280C Helicopters |
| aircraft | Enstrom Helicopter Corporation, The | F-28C | Airworthiness Directives; Enstrom Model F28, F28A, F28C, 280 and 280C Helicopters |
Unsafe Condition
Tail rotor spindle P/N 28-15202 may fail due to fatigue cracking, leading to loss of tail rotor control.
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Required Actions
Replace tail rotor spindle P/N 28-15202 with new P/N 28-15202-13 or manufacturer-reworked spindle with eight-character serial number. Install strike tabs P/N 28-17308 on blade leading edge.
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Compliance Time
within the next 50 hours time in service or six (6) months calendar time, whichever occurs first
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Affected Aircraft
Enstrom Models F28, F28A, F28C, 280, and 280C helicopters with 3.3 inch tail rotor blade and spindle P/N 28-15202
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Federal Register Abstract
Tail Rotor Spindle
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_77-20-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 77-20-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Enstrom Model F28, F28A, F28C, 280 and 280C Helicopters Subject: Tail Rotor Spindle Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 10/06/1977 Make: Enstrom Helicopter Corporation, The Model: 280 | 280C | F-28 | F-28A | F-28C Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 77-20-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3046 AD NUMBER: 77-20-02 SUBJECT HEADING: Airworthiness Directives; Enstrom Model F28, F28A, F28C, 280 and 280C Helicopters ACTION: SUMMARY: DATES: Effective October 6, 1977. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 77-20-02 ENSTROM: Amendment 39-3046. Applies to Enstrom Models F28, F28A, F28C, 280 and 280C helicopters certificated in all categories with a 3.3 inch tail rotor blade with spindle P/N 28-15202. Within the next 50 hours time in service or six (6) months calendar time, whichever occurs first, accomplish the following unless already complied with: 1. Replace tail rotor spindle P/N 28-15202 with a new spindle P/N 28-15202-13 or a manufacturer-reworked spindle which may be identified by an eight (8) character serial number acid-etched on the outside of the spindle center section. Reference should be made to Enstrom Maintenance Manual Section 15 for disassembly and reassembly instructions. Special care should be taken to have the three bearing stack positioned with the closed side toward the hub and the retaining nut properly torqued to 35-40 foot-pounds and safetied. 2. Install strike tabs P/N 28-17308 extending forward on the blade leading edge under the outer balancing screw. This supersedes Amendment 39-2839 (42 FR 10841) AD 77-04-04. This amendment is effective October 6, 1977, and was effective for all recipients of the airmail letter dated August 8, 1977, as amended by airmail letter dated August 22, 1977, upon receipt thereof. FOOTER:
Document Text
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AD Final Rules - DRS_77-20-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 77-20-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Enstrom Model F28, F28A, F28C, 280 and 280C Helicopters Subject: Tail Rotor Spindle Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 10/06/1977 Make: Enstrom Helicopter Corporation, The Model: 280 | 280C | F-28 | F-28A | F-28C 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: 77-20-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3046 AD NUMBER: 77-20-02 SUBJECT HEADING: Airworthiness Directives; Enstrom Model F28, F28A, F28C, 280 and 280C Helicopters ACTION: SUMMARY: DATES: Effective October 6, 1977. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 77-20-02 ENSTROM: Amendment 39-3046. Applies to Enstrom Models F28, F28A, F28C, 280 and 280C helicopters certificated in all categories with a 3.3 inch tail rotor blade with spindle P/N 28-15202. Within the next 50 hours time in service or six (6) months calendar time, whichever occurs first, accomplish the following unless already complied with: 1. Replace tail rotor spindle P/N 28-15202 with a new spindle P/N 28-15202-13 or a manufacturer-reworked spindle which may be identified by an eight (8) character serial number acid-etched on the outside of the spindle center section. Reference should be made to Enstrom Maintenance Manual Section 15 for disassembly and reassembly instructions. Special care should be taken to have the three bearing stack positioned with the closed side toward the hub and the retaining nut properly torqued to 35-40 foot-pounds and safetied. 2. Install strike tabs P/N 28-17308 extending forward on the blade leading edge under the outer balancing screw. This supersedes Amendment 39-2839 (42 FR 10841) AD 77-04-04. This amendment is effective October 6, 1977, and was effective for all recipients of the airmail letter dated August 8, 1977, as amended by airmail letter dated August 22, 1977, upon receipt thereof. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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