Main Rotor Gearbox - Main Rotor Shaft - Inspection / Replacement
- Published
- Effective
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Affected operators must comply with the AD by September 10, 2026. They need to review and update component history cards for each MRS, perform nondestructive inspections as required, mark REL MRS accordingly, and remove from service any MRS exceeding the new retirement life limits. Replacement or removal of MRS must occur at the next main gearbox overhaul or sooner if hours exceed the new limits.
Summary
The Federal Aviation Administration's Airworthiness Directive 2026-15-17 is a final rule addressing the main rotor shaft (MRS) inspection and replacement requirements for various helicopter models including Sikorsky S-61 variants, Croman SH-3H, Carson S-61L and SH-3H, Glacier CH-3E, Robinson Air Crane CH-3 and HH-3 variants, and Siller CH-3E and SH-3A helicopters. This directive updates life limits and inspection protocols for MRS part numbers S6135-20640-001, S6135-20640-002, and S6137-23040-001 to ensure continued airworthiness and safety.
What changed
This AD supersedes AD 2015-20-12 by reducing the retirement life of certain non-repetitive external lift (Non-REL) main rotor shafts from 13,000 hours to 7,300 hours time-in-service. It retains previous inspection and marking requirements but incorporates updated life limits based on new design re-evaluation and fatigue testing. The AD also updates type certificate holder names for some affected helicopter models.
Why it matters
The updated life limits and inspection requirements are critical to preventing fatigue cracks and potential structural failure of the main rotor shaft, which could lead to loss of main rotor power and helicopter control. Operators, maintenance organizations, and compliance teams must adhere to these revised limits to maintain safety and regulatory compliance. Failure to comply could result in unsafe flight conditions and regulatory penalties.
More for Sikorsky S-61
All 6- EASA AD US-2026-11-05Rotorcraft Flight Control - Auxiliary Servo Assembly - InspectionsJun 8, 2026
- EASA AD 2015-0226R8Equipment / Furnishings — Hoist — Test / ReplacementJul 16, 2025
- EASA AD US-2021-05-19Tail Rotor Control System - Arm Assembly - Life LimitApr 6, 2021
- EASA AD 2020-0039Fire Protection — Hand-held Fire Extinguishers — ReplacementFeb 27, 2020
- EASA SIB 2007-13FAA SAIB NE-07-30 - Sikorsky Aircraft S-61 Series Helicopters - Blade Inspection Method (BIM) System
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