AD 84-11-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-61A | Airworthiness Directives; SIKORSKY AIRCRAFT DIVISION Model S-61 L/N/A Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61L | Airworthiness Directives; SIKORSKY AIRCRAFT DIVISION Model S-61 L/N/A Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61N | Airworthiness Directives; SIKORSKY AIRCRAFT DIVISION Model S-61 L/N/A Series Helicopters |
Unsafe Condition
Flange failure due to cracks in flanges (Part Numbers S6135-66228-0, S6135-64013-0, S6135-66657-0) surrounding bolt attachments.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect flanges with over 800 hours time in service for cracks using a 5-power magnifying glass within 15 hours time in service after AD effective date. If cracks found, replace flange and ensure proper alignment of intermediate gearbox, tail gearbox, and pylon drive shaft before further flight. Allow equivalent methods or interval adjustments upon FAA approval with substantiating data.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within 15 hours time in service after the effective date of this AD
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Affected Aircraft
Sikorsky Model S-61 L/N/A series helicopters with flanges P/N S6135-66228-0, S6135-64013-0, or S6135-66657-0 in the tail rotor drive system.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Possible Flange Failure
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_84-11-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 84-11-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; SIKORSKY AIRCRAFT DIVISION Model S-61 L/N/A Series Helicopters Subject: Possible Flange Failure Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 06/06/1984 Make: Sikorsky Aircraft Corporation Model: S-61A | S-61L | S-61N Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 84-11-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-4866 AD NUMBER: 84-11-03 SUBJECT HEADING: Airworthiness Directives; SIKORSKY AIRCRAFT DIVISION Model S-61 L/N/A Series Helicopters ACTION: SUMMARY: DATES: Effective June 6, 1984. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 84-11-03 SIKORSKY AIRCRAFT DIVISION: Amendment 39-4866. Applies to all Sikorsky Model S-61 L/N/A series helicopters, certificated in all categories and authorized for flight with gross weights in excess of 19,500 pounds, when equipped with the following tail rotor drive system components: a. Flange Part Number (P/N) S6135-66228-0 installed at the input and output couplings of the intermediate gearbox. b. Flange P/N S6135-64013-0 installed at either end of the pylon drive shaft and at the aft end of the section IV tail drive shaft (shaft immediately forward of the intermediate gearbox). c. Flange P/N S6135-66657-0 installed at the input coupling of the tail gearbox. Compliance is required as indicated (unless already accomplished). To intercept impending failure of the flanges identified above, accomplish the following: d. For flanges with more than 800 hours time in service since new, inspect the flange for cracks utilizing a 5-power or greater magnifying glass in the area surrounding the bolt attachments within the next 15 hours time in service after the effective date of this AD, unless already accomplished, and thereafter at intervals no to exceed 15 hours time in service from the last inspection. e. If cracks are found, replace the flange and assure proper alignment of intermediate gearbox, tail gearbox, and pylon drive shaft before further flight. f. Upon request, with substantiating data submitted through an FAA maintenance inspector, equivalent methods of compliance or adjustment in the inspection intervals or compliance time may be approved by the Manager, Boston Aircraft Certification Branch, FAA, New England Region. This amendment becomes effective June 6, 1984. FOOTER:
Document Text
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AD Final Rules - DRS_84-11-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 84-11-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; SIKORSKY AIRCRAFT DIVISION Model S-61 L/N/A Series Helicopters Subject: Possible Flange Failure Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 06/06/1984 Make: Sikorsky Aircraft Corporation Model: S-61A | S-61L | S-61N 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: 84-11-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-4866 AD NUMBER: 84-11-03 SUBJECT HEADING: Airworthiness Directives; SIKORSKY AIRCRAFT DIVISION Model S-61 L/N/A Series Helicopters ACTION: SUMMARY: DATES: Effective June 6, 1984. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 84-11-03 SIKORSKY AIRCRAFT DIVISION: Amendment 39-4866. Applies to all Sikorsky Model S-61 L/N/A series helicopters, certificated in all categories and authorized for flight with gross weights in excess of 19,500 pounds, when equipped with the following tail rotor drive system components: a. Flange Part Number (P/N) S6135-66228-0 installed at the input and output couplings of the intermediate gearbox. b. Flange P/N S6135-64013-0 installed at either end of the pylon drive shaft and at the aft end of the section IV tail drive shaft (shaft immediately forward of the intermediate gearbox). c. Flange P/N S6135-66657-0 installed at the input coupling of the tail gearbox. Compliance is required as indicated (unless already accomplished). To intercept impending failure of the flanges identified above, accomplish the following: d. For flanges with more than 800 hours time in service since new, inspect the flange for cracks utilizing a 5-power or greater magnifying glass in the area surrounding the bolt attachments within the next 15 hours time in service after the effective date of this AD, unless already accomplished, and thereafter at intervals no to exceed 15 hours time in service from the last inspection. e. If cracks are found, replace the flange and assure proper alignment of intermediate gearbox, tail gearbox, and pylon drive shaft before further flight. f. Upon request, with substantiating data submitted through an FAA maintenance inspector, equivalent methods of compliance or adjustment in the inspection intervals or compliance time may be approved by the Manager, Boston Aircraft Certification Branch, FAA, New England Region. This amendment becomes effective June 6, 1984. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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