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Proposed rule

Airworthiness Directives; Various Helicopters

Built by the Tribune's code from the Federal Register. No AI wrote this page. Published in the Federal Register April 21, 2026. Document 2026-07720. Updated Nov. 12, 2026.

What it does

The FAA proposes to supersede Airworthiness Directive (AD) 2015-20-12, which applies to certain Sikorsky Aircraft Corporation Model S-61A, D, E, L, N, NM serial number (S/N) 61454, R, and V; Croman Corporation Model SH-3H; Carson Helicopters, Inc., Model S-61L and SH- 3H; Glacier Helicopter, Inc., Model CH-3E; Robinson Air Crane, Inc., Model CH-3E, CH-3C, HH-3C and HH-3E; and Siller Helicopters Model CH-3E and SH-3A helicopters. AD 2015-20-12 requires calculating or recalculating the hours time-in-service (TIS) of the main rotor shaft (MRS), determining whether the MRS is repetitive external lift (REL) or non-REL, performing a nondestructive inspection (NDI) for cracks, replacing any MRS that has cracks, replacing parts before their life limits and removing from service any parts that have exceeded their life limits. This proposed AD would also require establishing retirement lives for each REL MRS, including reducing life limits and allowing for modification of life limits based on service information, and removing any MRS with oversized dowel pin bores. Since the FAA issued AD 2015-20-12, a design re-evaluation shows that the MRS on certain helicopter models requires a lower life limit. This proposed AD would retain some of the requirements of AD 2015-20-12, and would also lower the retirement life for a certain MRS installed on certain helicopters and would update the type certificate holder name for some of the affected helicopter models. The FAA is proposing this AD to address the unsafe condition on these products.

The Federal Aviation Administration's summary, as published in the Federal Register.

What it would change

1 part of Title 14 of the Code of Federal Regulations:

14 CFR 39

Before this

747 earlier Federal Register documents under regulation identifier 2120-AA64 since Jan. 1, 2025.

Since then:

What happens next and when

The FAA must receive comments on this proposed AD by June 5, 2026.

The agency's dates, word for word.

Check it yourself

The record as published

Document number2026-07720
ActionNotice of proposed rulemaking (NPRM).
AgenciesTransportation Department; Federal Aviation Administration
PublishedApril 21, 2026
Comments closeJune 5, 2026
Regulation identifier (RIN)2120-AA64
DocketFAA-2026-3488

Source: the Federal Register (public domain). The document in the Federal Register