AD 78-21-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-58BT | Airworthiness Directives; Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58DT | Airworthiness Directives; Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58ET | Airworthiness Directives; Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58FT | Airworthiness Directives; Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58HT | Airworthiness Directives; Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58JT | Airworthiness Directives; Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT Helicopters |
Unsafe Condition
Tail rotor instability due to insufficient abrasion protection on tail rotor blades and inadequate control rod assembly.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install improved abrasion strips using Sikorsky Modification Kit 58070-10008-011 on specified tail rotor blades and install Sikorsky control rod assembly P/N 58400-64010-101.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within 200 hours time in service or three months, whichever comes first, after the effective date of this AD
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT helicopters certificated in all categories.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Tail Rotor Blades
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_78-21-05.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 78-21-05 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT Helicopters Subject: Tail Rotor Blades Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 11/30/1978 Make: Sikorsky Aircraft Corporation Model: S-58BT | S-58DT | S-58ET | S-58FT | S-58HT | S-58JT 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: 78-21-05 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3322 AD NUMBER: 78-21-05 SUBJECT HEADING: Airworthiness Directives; Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT Helicopters ACTION: SUMMARY: DATES: Effective November 30, 1978. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 78-21-05 SIKORSKY AIRCRAFT: Amendment 39-3322. Applies to S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT helicopters certificated in all categories. To prevent possible tail rotor instability accomplish the following: Within 200 hours time in service or three months, whichever comes first, after the effective date of this AD, unless already accomplished, complete the following: (a) Install improved abrasion strips, Sikorsky Modification Kit 58070-10008-011, on tail rotor blades, P/Ns S1615-30100-3, -4, -7, -10, -11, -15, -16, -041, -042, and -043. This modification is covered by Sikorsky Service Bulletin No. 58B15-18. (b) Install Sikorsky control rod assembly, P/N 58400-64010-101. This modification is covered by Sikorsky Service Bulletin No. 58B40-5. This amendment becomes effective November 30, 1978. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_78-21-05.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 78-21-05 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT Helicopters Subject: Tail Rotor Blades Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 11/30/1978 Make: Sikorsky Aircraft Corporation Model: S-58BT | S-58DT | S-58ET | S-58FT | S-58HT | S-58JT 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: 78-21-05 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3322 AD NUMBER: 78-21-05 SUBJECT HEADING: Airworthiness Directives; Sikorsky Models S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT Helicopters ACTION: SUMMARY: DATES: Effective November 30, 1978. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 78-21-05 SIKORSKY AIRCRAFT: Amendment 39-3322. Applies to S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT helicopters certificated in all categories. To prevent possible tail rotor instability accomplish the following: Within 200 hours time in service or three months, whichever comes first, after the effective date of this AD, unless already accomplished, complete the following: (a) Install improved abrasion strips, Sikorsky Modification Kit 58070-10008-011, on tail rotor blades, P/Ns S1615-30100-3, -4, -7, -10, -11, -15, -16, -041, -042, and -043. This modification is covered by Sikorsky Service Bulletin No. 58B15-18. (b) Install Sikorsky control rod assembly, P/N 58400-64010-101. This modification is covered by Sikorsky Service Bulletin No. 58B40-5. This amendment becomes effective November 30, 1978. FOOTER:
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Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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