SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments using a method listed under ADDRESSES . Include “Docket No. FAA-2026-4650; Project Identifier MCAI-2026-00514-R” at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this final rule because of those comments.

Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this final rule.

Confidential Business Information

CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this AD contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this AD, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this AD. Submissions containing CBI should be sent to Soban Saeed, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

The FAA issued Emergency AD 2026-10-51, dated May 15, 2026 (also referred to as the emergency AD), to address an unsafe condition on Hélicoptères Guimbal Model Cabri G2 helicopters. The FAA sent the emergency AD to all known U.S. owners and operators of these helicopters. The emergency AD requires inspecting the MR mast for cracks and corrosion pitting, and depending on the results of the inspection, the emergency AD requires accomplishing the corrective actions. The emergency AD also requires modifying the MR mast, which includes applying corrosion protection to the MR mast and reporting inspection results within 14 days after accomplishment of the inspection. The emergency AD prohibits installing an MGB having part number (P/N) G21-10-000, P/N G21-10-001, P/N G21-10-002, or P/N G21-10-003, unless certain requirements are met.

Emergency AD 2026-10-51 was prompted by European Union Aviation Safety Agency (EASA) Emergency AD 2026-0095-E, dated May 12, 2026 (also referred to as the MCAI), issued by EASA, which is the Technical Agent for ( printed page 34741) the Member States of the European Union, to correct an unsafe condition on Hélicoptères Guimbal Model Cabri G2 helicopters. The MCAI states a report was received of a crack on the MR mast after the crew reported an abnormal increase of vibration.

The FAA is issuing this AD to detect and correct any cracks or corrosion on the MR mast. This condition, if not detected and corrected, could lead to failure of the MR mast, possibly resulting in loss of control of the helicopter.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-4650.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed Guimbal Service Bulletin SB 26-009 B, Revision B, dated May 13, 2026. This material specifies procedures for disassembly of the MR mast, inspection of the MR mast for a crack or corrosion pitting, and corrective actions, which include removing affected parts from service and contacting HG customer support for further instructions.

The FAA also reviewed Guimbal Service Bulletin SB 18-023 E, Revision E, dated May 13, 2026, which specifies procedures for inspecting the MR mast for corrosion and applying protective coatings.

This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

FAA's Determination

These products have been approved by the civil aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI and material referenced above. The FAA is issuing this AD after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.

AD Requirements

This AD requires accomplishing the actions specified in the material already described, except as discussed under “Differences Between this AD and the Referenced Material.”

Differences Between This AD and the Referenced Material

Where the referenced material specifies contacting HG for repair instructions or corrective actions, this AD requires using a method approved by the FAA, EASA, or Hélicoptères Guimbal's EASA Design Organization Approval (DOA).

Interim Action

The FAA considers that this AD is an interim action. If final action is later identified, the FAA might consider additional rulemaking.

Justification for Immediate Adoption and Determination of the Effective Date

Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for “good cause,” finds that those procedures are “impracticable, unnecessary, or contrary to the public interest.” Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause.

An unsafe condition exists that required the immediate adoption of Emergency AD 2026-10-51, issued on May 15, 2026, to all known U.S. owners and operators of these helicopters. The FAA found that the risk to the flying public justified forgoing notice and comment prior to adoption of this rule because the MR mast is critical to flight of a helicopter. Cracking of the MR mast may lead to destruction of the MR mast, departure of the main rotor head, and loss of control of the helicopter. Since the FAA has no information pertaining to the extent of cracking of the MR mast that may currently exist in helicopters, the initial actions required by this AD must be accomplished before further flight for certain helicopters. This compliance time is shorter than the time necessary for the public to comment and for the publication of the final rule. These conditions still exist, therefore, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b).

In addition, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days, for the same reasons the FAA found good cause to forego notice and comment.

Regulatory Flexibility Act

The requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because FAA has determined that it has good cause to adopt this rule without prior notice and comment, RFA analysis is not required.

Costs of Compliance

The FAA estimates that this AD affects 67 helicopters of U.S. registry.

The FAA estimates the following costs to comply with this AD:

The FAA estimates the following costs to do any necessary repairs that would be required based on the results of the inspection. The agency has no way of determining the number of helicopters that might need this repair:

The extent of the MR mast repairs that may be needed could vary significantly from helicopter to helicopter. The FAA has no way of determining the work-hours it may take to perform these repairs or the number of helicopters that may require repair. However, according to the manufacturer, the cost of an MR mast repair (overhaul) may cost up to $19,950 per repair.

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a currently valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to be approximately 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. All responses to this collection of information are mandatory. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to: Information Collection Clearance Officer, Federal Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177-1524.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866, and

(2) Will not affect intrastate aviation in Alaska.

The Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: