AD 72-25-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-61A | Airworthiness Directives; Sikorsky Models S-61A, S-61B, S-61D, S-61L, S-61N Series, S-61R, and S-61V Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61D | Airworthiness Directives; Sikorsky Models S-61A, S-61B, S-61D, S-61L, S-61N Series, S-61R, and S-61V Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61L | Airworthiness Directives; Sikorsky Models S-61A, S-61B, S-61D, S-61L, S-61N Series, S-61R, and S-61V Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61N | Airworthiness Directives; Sikorsky Models S-61A, S-61B, S-61D, S-61L, S-61N Series, S-61R, and S-61V Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61R | Airworthiness Directives; Sikorsky Models S-61A, S-61B, S-61D, S-61L, S-61N Series, S-61R, and S-61V Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61V | Airworthiness Directives; Sikorsky Models S-61A, S-61B, S-61D, S-61L, S-61N Series, S-61R, and S-61V Helicopters |
Unsafe Condition
Cracked primary servo mounting bracket retaining nuts could cause loss of main rotor control.
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Required Actions
Remove all MS21042-6 or MS20365-624C retaining nuts from the primary servo mounting brackets (P/N S613520249) and replace with P/N MS21045-6 retaining nuts in accordance with Sikorsky Service Bulletin No. 61B35-18. Equivalent methods of compliance require approval.
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Compliance Time
Within the next 25 hours time in service after the effective date of this Airworthiness Directive
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Affected Aircraft
Sikorsky Models S-61A, S-61B, S-61D, S-61L Series prior to SS No. 61454, S-61N Series prior to SS No. 61493, S-61R, S-61V helicopters.
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Federal Register Abstract
Loss of Main Rotor Control
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_72-25-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 72-25-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Sikorsky Models S-61A, S-61B, S-61D, S-61L, S-61N Series, S-61R, and S-61V Helicopters Subject: Loss of Main Rotor Control Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/15/1972 Make: Sikorsky Aircraft Corporation Model: S-61A | S-61D | S-61L | S-61N | S-61R | S-61V 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: 72-25-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1571 AD NUMBER: 72-25-04 SUBJECT HEADING: Airworthiness Directives; Sikorsky Models S-61A, S-61B, S-61D, S-61L, S-61N Series, S-61R, and S-61V Helicopters ACTION: SUMMARY: DATES: Effective December 15, 1972. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 72-25-04 SIKORSKY: Amdt. 39-1571. Applies to all Sikorsky S-61A, S-61B, S-61D, S- 61L Series prior to SS No. 61454, S-61N Series prior to SS No. 61493, S-61R, S-61V helicopters certificated in all categories. Compliance required as indicated. To prevent hazards in flight due to loss of main rotor control as a result of cracked primary servo mounting bracket retaining nuts, accomplish the following: (a) Within the next 25 hours time in service after the effective date of this Airworthiness Directive, remove all MS21042-6 or MS20365-624C retaining nuts from the primary servo mounting brackets, P/N S613520249, and replace with P/N MS21045-6 retaining nuts in accordance with Sikorsky Service Bulletin No. 61B35-18 dated 10 November 1972 or later revision approved by the Chief, Engineering and Manufacturing Branch, FAA, New England Region. (b) Upon request with substantiation data submitted through an FAA maintenance inspector, the compliance time specified in this AD may be increased by the Chief, Engineering and Manufacturing Branch, FAA, New England Region. (c) Equivalent methods of compliance must be approved by the Chief, Engineering and Manufacturing Branch, FAA, New England Region. This amendment becomes effective December 15, 1972. FOOTER:
Document Text
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AD Final Rules - DRS_72-25-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 72-25-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Sikorsky Models S-61A, S-61B, S-61D, S-61L, S-61N Series, S-61R, and S-61V Helicopters Subject: Loss of Main Rotor Control Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/15/1972 Make: Sikorsky Aircraft Corporation Model: S-61A | S-61D | S-61L | S-61N | S-61R | S-61V 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: 72-25-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-1571 AD NUMBER: 72-25-04 SUBJECT HEADING: Airworthiness Directives; Sikorsky Models S-61A, S-61B, S-61D, S-61L, S-61N Series, S-61R, and S-61V Helicopters ACTION: SUMMARY: DATES: Effective December 15, 1972. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 72-25-04 SIKORSKY: Amdt. 39-1571. Applies to all Sikorsky S-61A, S-61B, S-61D, S- 61L Series prior to SS No. 61454, S-61N Series prior to SS No. 61493, S-61R, S-61V helicopters certificated in all categories. Compliance required as indicated. To prevent hazards in flight due to loss of main rotor control as a result of cracked primary servo mounting bracket retaining nuts, accomplish the following: (a) Within the next 25 hours time in service after the effective date of this Airworthiness Directive, remove all MS21042-6 or MS20365-624C retaining nuts from the primary servo mounting brackets, P/N S613520249, and replace with P/N MS21045-6 retaining nuts in accordance with Sikorsky Service Bulletin No. 61B35-18 dated 10 November 1972 or later revision approved by the Chief, Engineering and Manufacturing Branch, FAA, New England Region. (b) Upon request with substantiation data submitted through an FAA maintenance inspector, the compliance time specified in this AD may be increased by the Chief, Engineering and Manufacturing Branch, FAA, New England Region. (c) Equivalent methods of compliance must be approved by the Chief, Engineering and Manufacturing Branch, FAA, New England Region. This amendment becomes effective December 15, 1972. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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