AD 91-12-01
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-61A | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61D | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61E | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61L | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61N | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61NM | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61R | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61V | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters |
Unsafe Condition
Failure of a main rotor blade spindle due to improper application of sealing compound between the spacer and spindle assembly, which could cause loss of the main rotor blade and subsequent loss of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Visually inspect sleeve and spindle assemblies for sealing compound integrity using an inspection mirror and flashlight. If sealing compound is missing or defective, conduct ultrasonic inspections for cracks or flaws. Replace spindle assemblies with cracks/flaws before flight. For intact sealing compound, perform one-time ultrasonic inspection within 200 hours. Record compliance in aircraft logs.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 10 hours time in service after receipt of this AD (for assemblies with 6 months/500 hours time in service since new/overhaul) or within 10 hours after reaching 6 months/500 hours time in service (for others).
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Model S-61A, S-61D, S-61E, S-61L, S-61N, S-61NM, S-61R, S-61V helicopters with main rotor head assemblies equipped with sleeve and spindle assemblies P/N S6110-23350-041 manufactured/overhauled before February 6, 1991.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Sleeve & Spindle Assemblies
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_91-12-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 91-12-01 Document Type: AD Final Rules Docket Number: 91-ASW-04 Subject Heading: Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters Subject: Sleeve & Spindle Assemblies Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 07/08/1991 Make: Sikorsky Aircraft Corporation Model: S-61A | S-61D | S-61E | S-61L | S-61N | S-61NM | 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: 91-12-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: 91-ASW-04 AMENDMENT: 39-7012 AD NUMBER: 91-12-01 SUBJECT HEADING: Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters ACTION: SUMMARY: DATES: Effective July 8, 1991. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 91-12-01 SIKORSKY AIRCRAFT: Amendment 39-7012. Docket No. 91-ASW-04. Supersedes AD 91-04-01. Applicability: All Model S-61 series helicopters, certificated in any category, on main rotor head assemblies equipped with sleeve and spindle assemblies, P/N S6110-23350-041, that were manufactured or overhauled prior to February 6, 1991. Compliance: Required as indicated, unless already accomplished. To prevent the failure of a main rotor blade spindle, which could cause loss of the main rotor blade and subsequent loss of the helicopter, accomplish the following: (a) Within the next 10 hours time in service after receipt of this AD, visually inspect all sleeve and spindle assemblies for evidence of proper application of sealing compound between the spacer, P/N S6112-23055-101, and the spindle assembly, P/N S6112-23027-041, on main rotor head assemblies equipped with sleeve and spindle assemblies, P/N S6110-23350-041, that have 6 months or 500 hours or more time in service on the effective date of this AD since new or the last overhaul. Visually inspect in accordance with paragraph (c) of this AD. (b) For main rotor head assemblies equipped with sleeve and spindle assemblies, P/N S6110-23350-041, that do not have 6 months or 500 hours time in service since new or overhaul, visually inspect the spindle assemblies for evidence of proper application of sealing compound between the spacer, P/N S6112-23055-101, and the spindle assembly, P/N S6112-23027-041, on main rotor head assemblies equipped with sleeve and spindle assemblies, P/N S6110-23350-041, in accordance with paragraph (c) of this AD. Conduct this inspection within 10 hours time in service after reaching 6 months or 500 hours time in service since new or overhaul, whichever comes first. NOTE: Two configurations of spacers exist. One has two puller slots spaced 180 degrees apart. The second has no puller slots. The spacers, P/N S6112-23055-101, affected by this AD have slots. (c) Utilizing an inspection mirror and flashlight, visually inspect all 5 rotor head sleeve and spindle assemblies for evidence of proper sealing compound application in the spacer slot area. (d) If the sealing compound is not present in the spacer slot, or if the sealant has voids, gaps, or pores, before further flight, inspect each suspect spindle, P/N S6112-23027-041, for crack or flaws in accordance with Sikorsky Aircraft Alert Service Bulletin (ASB) No. 61B10-48, dated January 18, 1991, using the ultrasonic inspection method. (e) If a crack or flaw indication is found in the spindle (from the inspections of paragraph (d)), replace the sleeve and spindle assembly prior to further flight with an airworthy component using standard maintenance instructions. (f) If no indication of cracks or flaws are found from the inspections of paragraph (d), return the sleeve and spindle assembly to service using ASB No. 61B10-48 and standard maintenance instructions and, thereafter, conduct repetitive ultrasonic inspections in accordance with paragraph (d) at intervals not to exceed 50 hours time in service. (g) For slotted sleeve and spindle assemblies that have the sealing compound intact in the slot area (i.e., that did not require ultrasonic inspection in accordance with paragraph (d) of this AD), conduct a one-time ultrasonic inspection of the spindle in accordance with ASB No. 61B10-48 within the next 200 hours time in service after the initial visual inspection required in either paragraph (a) or (b) of this AD. (h) An alternate method of compliance with the inspections and rework of paragraph (a) through (g) can be accomplished by tearing down the sleeve and spindle assembly as specified in Part 3 of ASB No. 61B10-48 and inspecting the spindle radius area for corrosion. If corrosion is found in the spindle radius area, replace the spindle assembly with an airworthy component. If no corrosion is found, reassemble and reseal the sleeve and spindle in accordance with Part 3 and reinstall on the rotor head in accordance with the maintenance manual. Sleeve and spindle assemblies that have been torn down, inspected, and resealed in accordance with Part 3 of ASB 61B10-48, are no longer required to comply with paragraphs (a), (b), (c), (d), (e), (f), or (g) above. (i) Record compliance with paragraphs (e), (f), (g) or (h) by part number, serial number and blade location in the aircraft logbook/maintenance records. (j) An alternate method of compliance or adjustment of the compliance times which provides an equivalent level of safety, may be used if approved by the Manager, Boston Aircraft Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, 12 New England Executive Park, Burlington, MA 01803. (k) In accordance with FAR 21.197 and 21.199, the helicopter may be flown to a base where the ultrasonic inspections required by this AD may be accomplished. The ultrasonic inspections and sleeve and spindle disassembly and the inspection for corrosion shall be done in accordance with pages 1 through 33 of Sikorsky Aircraft Alert Service Bulletin No. 61B10-48, dated January 18, 1991. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Sikorsky Aircraft, 6900 Main Street, Stratford, Connecticut 06601-1380, Attn: Commercial Customer Support. Copies may be inspected at the Rules Docket, Office of the Assistant Chief Counsel, Southwest Region, Federal Aviation Administration, 4400 Blue Mound Road, Building 3B, Room 158, Fort Worth, Texas 76193, or at the Office of the Federal Register, 1100 L Street, Room 8401, Washington, DC 20591. Amendment 39-7012 supersedes Priority Letter AD 91-04-01, issued on February 6, 1991. This amendment (39-7012 AD 91-12-01) becomes effective on July 8, 1991. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_91-12-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 91-12-01 Document Type: AD Final Rules Docket Number: 91-ASW-04 Subject Heading: Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters Subject: Sleeve & Spindle Assemblies Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 07/08/1991 Make: Sikorsky Aircraft Corporation Model: S-61A | S-61D | S-61E | S-61L | S-61N | S-61NM | 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: 91-12-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: 91-ASW-04 AMENDMENT: 39-7012 AD NUMBER: 91-12-01 SUBJECT HEADING: Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61 Series Helicopters ACTION: SUMMARY: DATES: Effective July 8, 1991. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 91-12-01 SIKORSKY AIRCRAFT: Amendment 39-7012. Docket No. 91-ASW-04. Supersedes AD 91-04-01. Applicability: All Model S-61 series helicopters, certificated in any category, on main rotor head assemblies equipped with sleeve and spindle assemblies, P/N S6110-23350-041, that were manufactured or overhauled prior to February 6, 1991. Compliance: Required as indicated, unless already accomplished. To prevent the failure of a main rotor blade spindle, which could cause loss of the main rotor blade and subsequent loss of the helicopter, accomplish the following: (a) Within the next 10 hours time in service after receipt of this AD, visually inspect all sleeve and spindle assemblies for evidence of proper application of sealing compound between the spacer, P/N S6112-23055-101, and the spindle assembly, P/N S6112-23027-041, on main rotor head assemblies equipped with sleeve and spindle assemblies, P/N S6110-23350-041, that have 6 months or 500 hours or more time in service on the effective date of this AD since new or the last overhaul. Visually inspect in accordance with paragraph (c) of this AD. (b) For main rotor head assemblies equipped with sleeve and spindle assemblies, P/N S6110-23350-041, that do not have 6 months or 500 hours time in service since new or overhaul, visually inspect the spindle assemblies for evidence of proper application of sealing compound between the spacer, P/N S6112-23055-101, and the spindle assembly, P/N S6112-23027-041, on main rotor head assemblies equipped with sleeve and spindle assemblies, P/N S6110-23350-041, in accordance with paragraph (c) of this AD. Conduct this inspection within 10 hours time in service after reaching 6 months or 500 hours time in service since new or overhaul, whichever comes first. NOTE: Two configurations of spacers exist. One has two puller slots spaced 180 degrees apart. The second has no puller slots. The spacers, P/N S6112-23055-101, affected by this AD have slots. (c) Utilizing an inspection mirror and flashlight, visually inspect all 5 rotor head sleeve and spindle assemblies for evidence of proper sealing compound application in the spacer slot area. (d) If the sealing compound is not present in the spacer slot, or if the sealant has voids, gaps, or pores, before further flight, inspect each suspect spindle, P/N S6112-23027-041, for crack or flaws in accordance with Sikorsky Aircraft Alert Service Bulletin (ASB) No. 61B10-48, dated January 18, 1991, using the ultrasonic inspection method. (e) If a crack or flaw indication is found in the spindle (from the inspections of paragraph (d)), replace the sleeve and spindle assembly prior to further flight with an airworthy component using standard maintenance instructions. (f) If no indication of cracks or flaws are found from the inspections of paragraph (d), return the sleeve and spindle assembly to service using ASB No. 61B10-48 and standard maintenance instructions and, thereafter, conduct repetitive ultrasonic inspections in accordance with paragraph (d) at intervals not to exceed 50 hours time in service. (g) For slotted sleeve and spindle assemblies that have the sealing compound intact in the slot area (i.e., that did not require ultrasonic inspection in accordance with paragraph (d) of this AD), conduct a one-time ultrasonic inspection of the spindle in accordance with ASB No. 61B10-48 within the next 200 hours time in service after the initial visual inspection required in either paragraph (a) or (b) of this AD. (h) An alternate method of compliance with the inspections and rework of paragraph (a) through (g) can be accomplished by tearing down the sleeve and spindle assembly as specified in Part 3 of ASB No. 61B10-48 and inspecting the spindle radius area for corrosion. If corrosion is found in the spindle radius area, replace the spindle assembly with an airworthy component. If no corrosion is found, reassemble and reseal the sleeve and spindle in accordance with Part 3 and reinstall on the rotor head in accordance with the maintenance manual. Sleeve and spindle assemblies that have been torn down, inspected, and resealed in accordance with Part 3 of ASB 61B10-48, are no longer required to comply with paragraphs (a), (b), (c), (d), (e), (f), or (g) above. (i) Record compliance with paragraphs (e), (f), (g) or (h) by part number, serial number and blade location in the aircraft logbook/maintenance records. (j) An alternate method of compliance or adjustment of the compliance times which provides an equivalent level of safety, may be used if approved by the Manager, Boston Aircraft Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, 12 New England Executive Park, Burlington, MA 01803. (k) In accordance with FAR 21.197 and 21.199, the helicopter may be flown to a base where the ultrasonic inspections required by this AD may be accomplished. The ultrasonic inspections and sleeve and spindle disassembly and the inspection for corrosion shall be done in accordance with pages 1 through 33 of Sikorsky Aircraft Alert Service Bulletin No. 61B10-48, dated January 18, 1991. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Sikorsky Aircraft, 6900 Main Street, Stratford, Connecticut 06601-1380, Attn: Commercial Customer Support. Copies may be inspected at the Rules Docket, Office of the Assistant Chief Counsel, Southwest Region, Federal Aviation Administration, 4400 Blue Mound Road, Building 3B, Room 158, Fort Worth, Texas 76193, or at the Office of the Federal Register, 1100 L Street, Room 8401, Washington, DC 20591. Amendment 39-7012 supersedes Priority Letter AD 91-04-01, issued on February 6, 1991. This amendment (39-7012 AD 91-12-01) becomes effective on July 8, 1991. FOOTER:
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