AD 2014-08-06
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-76A | Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-76B | Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-76C | Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters |
Unsafe Condition
Failure of a bifilar lug, damage to the main rotor system, and subsequent loss of control of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect the main rotor lower bifilar arm assembly for cracks and replace it if a crack is found. Test for correct torque on the lug nuts and conduct torque stabilization tests if necessary. Replace the main rotor hub (MRH) pilot with part number 76103-08003-102 as terminating action.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Effective June 2, 2014.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Aircraft Corporation Model S-76A, S-76B, and S-76C helicopters with a certain MRH pilot installed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Main Rotor Head
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - 2014-08-06.pdf Copy URL Document Versions Feedback DetailsAttachments/Public Comments AD Number: 2014-08-06 Document Type: AD Final Rules Docket Number: FAA-2013-0637 Subject Heading: Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters Subject: Main Rotor Head Status: Current Citation: Federal Register Volume 79, Number 81 (Monday, April 28, 2014) Citation Publish Date: 04/28/2014 Effective Date: 06/02/2014 Make: Sikorsky Aircraft Corporation Model: S-76A | S-76B | S-76C Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: 2005-22-01 Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: Automatic Zoom Actual Size Page Fit Page Width 50% 75% 100% 125% 150% 200% 300% 400% 125% of 6 1 [Federal Register Volume 79, Number 81 (Monday, April 28, 2014)] [Rules and Regulations] [Pages 23260-23262] From the Federal Register Online via the Government Printing Office [www.gpo.gov] [FR Doc No: 2014-08849] –––––––––––––––––––––––––––––––––– DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA-2013-0637; Directorate Identifier 2013-SW-030-AD; Amendment 39-17830; AD 2014-08-06] RIN 2120-AA64 Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. –––––––––––––––––––––––––––––––––– SUMMARY: We are superseding Airworthiness Directive (AD) 2005-22-01 for Sikorsky Aircraft Corporation (Sikorsky) Model S-76A, B, and C helicopters. AD 2005-22-01 required inspecting the main rotor lower bifilar arm assembly (bifilar arm assembly) for a crack, and if there is a crack, replacing the bifilar arm assembly. AD 2005-22-01 also required a one-time test for the correct torque on the lug nuts, and if necessary, conducting torque stabilization tests. This new AD retains the requirements of AD 2005-22-01 and also requires replacing the main rotor hub (MRH) pilot with a different part-numbered MRH pilot, which is terminating action for the requirements of the AD. This AD was prompted by the development of a terminating procedure for the inspections required by AD 2005-22-01. We are issuing this AD to prevent failure of a bifilar lug, damage to the main rotor system, and subsequent loss of control of the helicopter. DATES: This AD is effective June 2, 2014. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of November 10, 2005 (70 FR 61721, October 26, 2005). ADDRESSES: For service information identified in this AD, contact Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical Support, mailstop s581a, 6900 Main Street, Stratford, CT 06614; telephone (800) 562-4409; email tsslibrary@sikorsky.com; or at http://www.sikorsky.com. You may review service information at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. Examining the AD Docket You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal 2 holidays. The AD docket contains this AD, any incorporated by reference service information, the economic evaluation, any comments received, and other information. The address for the Docket Office (phone: 800-647-5527) is Document Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Nicholas Faust, Aviation Safety Engineer, Boston Aircraft Certification Office, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, Massachusetts 01803; telephone (781) 238-7763; email nicholas.faust@faa.gov. SUPPLEMENTARY INFORMATION: Discussion We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2005-22-01, Amendment 39-14345 (70 FR 61721, October 26, 2005) (AD 2005-22-01). AD 2005- 22-01 applied to Sikorsky Model S-76A, B, and C helicopters with a certain MRH pilot installed. The NPRM published in the Federal Register on July 23, 2013 (78 FR 44048). AD 2005-22-01 required repetitively inspecting the bifilar arm assembly for a crack, and replacing the bifilar arm assembly if it has a crack. If there is not a crack, AD 2005-22-01 required a one-time test for the correct torque on the lug nuts, and if necessary, conducting torque stabilization. After we issued AD 2005-22-01, Sikorsky produced a newly-redesigned pilot with a larger flange diameter that provides greater support for the bifilar assembly and reduces stress on the bifilar assembly attachment lugs. The NPRM proposed to retain the repetitive inspection requirements of AD 2005-22-01, but also proposed to require replacing the MRH pilot, part number (P/N) 76103- 08003-101, with newly-redesigned MRH pilot, P/N 76103-08003-102, as terminating action. Related Service Information Sikorsky issued S-76 Alert Service Bulletin (ASB) 76-65-62, dated December 14, 2004, which describes procedures for inspecting the lower bifilar assembly for a crack. Sikorsky has also issued ASB 76-65-65, Basic Issue, dated March 22, 2012, which specifies measuring the MRH diameter and, if the diameter is small, replacing the MRH pilot with a newly-redesigned MRH pilot with a larger flange diameter. Comments We gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM (78 FR 44048, July 23, 2013) or on the determination of the cost to the public. Costs of Compliance We estimate that this AD affects 181 helicopters of U.S. Registry. We estimate that operators may incur the following costs in order to comply with this AD: • Inspecting the bifilar arm assembly requires about 4 work-hours, at an average labor rate of $85 per hour, for a cost per helicopter of $340 and a total cost to U.S. operators of $61,540. • Replacing a cracked bifilar arm assembly requires about 4 work-hours, at an average labor rate of $85 per hour, and required parts cost about $19,727, for a cost per helicopter of $20,067.
Document Text
Show stored source text (verify against official source)
AD Final Rules - 2014-08-06.pdf Copy URL Document Versions Feedback DetailsAttachments/Public Comments AD Number: 2014-08-06 Document Type: AD Final Rules Docket Number: FAA-2013-0637 Subject Heading: Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters Subject: Main Rotor Head Status: Current Citation: Federal Register Volume 79, Number 81 (Monday, April 28, 2014) Citation Publish Date: 04/28/2014 Effective Date: 06/02/2014 Make: Sikorsky Aircraft Corporation Model: S-76A | S-76B | S-76C Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: 2005-22-01 Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: Automatic Zoom Actual Size Page Fit Page Width 50% 75% 100% 125% 150% 200% 300% 400% 125% of 6 1 [Federal Register Volume 79, Number 81 (Monday, April 28, 2014)] [Rules and Regulations] [Pages 23260-23262] From the Federal Register Online via the Government Printing Office [www.gpo.gov] [FR Doc No: 2014-08849] –––––––––––––––––––––––––––––––––– DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA-2013-0637; Directorate Identifier 2013-SW-030-AD; Amendment 39-17830; AD 2014-08-06] RIN 2120-AA64 Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. –––––––––––––––––––––––––––––––––– SUMMARY: We are superseding Airworthiness Directive (AD) 2005-22-01 for Sikorsky Aircraft Corporation (Sikorsky) Model S-76A, B, and C helicopters. AD 2005-22-01 required inspecting the main rotor lower bifilar arm assembly (bifilar arm assembly) for a crack, and if there is a crack, replacing the bifilar arm assembly. AD 2005-22-01 also required a one-time test for the correct torque on the lug nuts, and if necessary, conducting torque stabilization tests. This new AD retains the requirements of AD 2005-22-01 and also requires replacing the main rotor hub (MRH) pilot with a different part-numbered MRH pilot, which is terminating action for the requirements of the AD. This AD was prompted by the development of a terminating procedure for the inspections required by AD 2005-22-01. We are issuing this AD to prevent failure of a bifilar lug, damage to the main rotor system, and subsequent loss of control of the helicopter. DATES: This AD is effective June 2, 2014. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of November 10, 2005 (70 FR 61721, October 26, 2005). ADDRESSES: For service information identified in this AD, contact Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical Support, mailstop s581a, 6900 Main Street, Stratford, CT 06614; telephone (800) 562-4409; email tsslibrary@sikorsky.com; or at http://www.sikorsky.com. You may review service information at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. Examining the AD Docket You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal 2 holidays. The AD docket contains this AD, any incorporated by reference service information, the economic evaluation, any comments received, and other information. The address for the Docket Office (phone: 800-647-5527) is Document Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590. FOR FURTHER INFORMATION CONTACT: Nicholas Faust, Aviation Safety Engineer, Boston Aircraft Certification Office, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, Massachusetts 01803; telephone (781) 238-7763; email nicholas.faust@faa.gov. SUPPLEMENTARY INFORMATION: Discussion We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2005-22-01, Amendment 39-14345 (70 FR 61721, October 26, 2005) (AD 2005-22-01). AD 2005- 22-01 applied to Sikorsky Model S-76A, B, and C helicopters with a certain MRH pilot installed. The NPRM published in the Federal Register on July 23, 2013 (78 FR 44048). AD 2005-22-01 required repetitively inspecting the bifilar arm assembly for a crack, and replacing the bifilar arm assembly if it has a crack. If there is not a crack, AD 2005-22-01 required a one-time test for the correct torque on the lug nuts, and if necessary, conducting torque stabilization. After we issued AD 2005-22-01, Sikorsky produced a newly-redesigned pilot with a larger flange diameter that provides greater support for the bifilar assembly and reduces stress on the bifilar assembly attachment lugs. The NPRM proposed to retain the repetitive inspection requirements of AD 2005-22-01, but also proposed to require replacing the MRH pilot, part number (P/N) 76103- 08003-101, with newly-redesigned MRH pilot, P/N 76103-08003-102, as terminating action. Related Service Information Sikorsky issued S-76 Alert Service Bulletin (ASB) 76-65-62, dated December 14, 2004, which describes procedures for inspecting the lower bifilar assembly for a crack. Sikorsky has also issued ASB 76-65-65, Basic Issue, dated March 22, 2012, which specifies measuring the MRH diameter and, if the diameter is small, replacing the MRH pilot with a newly-redesigned MRH pilot with a larger flange diameter. Comments We gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM (78 FR 44048, July 23, 2013) or on the determination of the cost to the public. Costs of Compliance We estimate that this AD affects 181 helicopters of U.S. Registry. We estimate that operators may incur the following costs in order to comply with this AD: • Inspecting the bifilar arm assembly requires about 4 work-hours, at an average labor rate of $85 per hour, for a cost per helicopter of $340 and a total cost to U.S. operators of $61,540. • Replacing a cracked bifilar arm assembly requires about 4 work-hours, at an average labor rate of $85 per hour, and required parts cost about $19,727, for a cost per helicopter of $20,067.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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