Opportunity
Federal Register #20261517
FAA Airworthiness Directive: Main Rotor Shaft Inspections and Life Limit Reductions for Sikorsky and Other Helicopters
Buyer
Federal Aviation Administration (FAA), Department of Transportation
Posted
August 06, 2026
Identifier
20261517
The Federal Aviation Administration (FAA), under the Department of Transportation, has issued a final rule updating airworthiness requirements for main rotor shafts (MRS) on multiple helicopter models. - Government Buyer: - Department of Transportation, Federal Aviation Administration, Aircraft Certification Service - OEMs Involved: - Sikorsky Aircraft Corporation - Croman Corporation - Carson Helicopters - Glacier Helicopter - Robinson Air Crane - Siller Helicopters - Products/Parts Affected: - Main Rotor Shaft (MRS) with part numbers: - S613520640001 - S613520640002 - S613723040001 - Key Requirements: - Mandates updated calculations for main rotor shaft usage - Requires nondestructive inspections for cracks - Imposes reduced retirement life limits for specified MRS part numbers (as low as 7,300 hours TIS for Non-REL MRS) - Requires marking of REL (reworked) MRS - Calls for removal of MRS with oversized dowel pin bores - Applies to 76 U.S. helicopters across several models (S-61A, D, E, L, N, NM, R, V; SH-3H; S-61L; CH-3E; CH-3C; HH-3C; HH-3E; SH-3A, etc.) - References Sikorsky Alert Service Bulletin No. 61B3569 for compliance procedures - Notable: This is a regulatory safety directive, not a procurement or purchase request.
Description
The FAA is superseding Airworthiness Directive (AD) 2015-20-12 for certain helicopter models including Sikorsky Aircraft Corporation, Croman Corporation, Carson Helicopters, Glacier Helicopter, Robinson Air Crane, and Siller Helicopters. The directive requires updated inspections and reduced retirement lives for main rotor shafts (MRS) based on a design re-evaluation that shows a lower life limit is necessary. It retains some previous requirements but modifies retirement lives and updates type certificate holder names. The AD aims to address unsafe conditions related to fatigue cracks in the MRS that could lead to structural failure and loss of control.