The FAA is adopting a new airworthiness directive (AD) for certain H[eacute]licopt[egrave]res Guimbal (HG) Model Cabri G2 helicopters. This AD was prompted by a report of a pote...
[Docket No. FAA-2026-4630; Project Identifier MCAI-2025-01824-R; Amendment 39-23472; AD 2026-19-05]
RIN 2120-AA64
AGENCY:
Federal Aviation Administration (FAA), DOT.
ACTION:
Final rule.
SUMMARY:
The FAA is adopting a new airworthiness directive (AD) for certain Hélicoptères Guimbal (HG) Model Cabri G2 helicopters. This AD was prompted by a report of a potential malfunction of the helicopter emergency locator transmitter (ELT) and subsequent findings of weak ELT signals on 121.5 MHz and 406 MHz frequencies due to improper antenna installation (location). This AD requires revising the existing rotorcraft flight manual (RFM) for the helicopter. The FAA is issuing this AD to address the unsafe condition on these products.
DATES:
This AD is effective November 2, 2026.
The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of November 2, 2026
ADDRESSES:
AD Docket:
You may examine the AD docket at
regulations.gov
under Docket No. FAA-2026-4630; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
Material Incorporated by Reference:
For Guimbal material identified in this AD, contact HG, 1070, rue du Lieutenant Parayre, Ae´rodrome d'Aix-en-Provence, 13290 Les Milles, France; phone: 33-04-42-39-10-88; email:support@guimbal.com;
website:
guimbal.com.
You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 10101 Hillwood Parkway, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110. It is also available atregulations.gov
under Docket No. FAA-2026-4630.
FOR FURTHER INFORMATION CONTACT:
David Enns, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4147; email:
david.enns@faa.gov.
SUPPLEMENTARY INFORMATION:
Background
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain HG Model Cabri G2 helicopters. The NPRM was published in the
Federal Register
on May 7, 2026 (91 FR 24752). The NPRM was prompted by European Union Aviation Safety Agency (EASA) AD 2025-0282, dated December 12, 2025 (EASA AD 2025-0282) (also referred to as the MCAI), issued by EASA, which is the Technical Agent for the Member States of the European Union. The MCAI states that a report of a potential malfunction of the helicopter ELT was received. Subsequent investigation revealed that due to improper antenna installation (location), the ELT produced a weaker signal than expected on 121.5 MHz and 406 MHz frequencies. The MCAI further states that both HG cockpit ELT antenna configurations are affected.
In the NPRM, the FAA proposed to require revising the existing RFM for the helicopter. The FAA is issuing this AD to address the unsafe condition on these products.
You may examine the MCAI in the AD docket at
regulations.gov
under Docket No. FAA-2026-4630.
Discussion of Final Airworthiness Directive
Comments
The FAA received a comment from one anonymous commenter. The following presents the comment received on the NPRM and the FAA's response to the comment.
( printed page 61119)
Request for Mandatory ELT Antenna Modification.
The commenter requested that the FAA revise the NPRM to convert the optional ELT antenna modification into a requirement and also require a 6-month compliance time associated with the modification. The commenter stated that the limitation specified in the RFM treats the symptom instead of the root cause. The commenter also stated that the underlying issue is that the antenna was improperly located inside the cockpit, and that the unsafe condition will persist until the modification is completed. Additionally, the commenter stated the NPRM omits the deadline of completing the modification within 6 months, which opens the possibility that an affected aircraft continues to fly with a degraded ELT.
The FAA disagrees that the ELT antenna modification should be required. EASA and FAA regulations differ regarding when an ELT is required. Specifically, under 14 CFR 135.168, FAA regulations require an ELT for part 135 overwater operations. Once the revision of the RFM limitations section that is required by this AD has been completed, overwater operations are prohibited until the modification has been performed, thereby eliminating the operational context in which a functional ELT is mandated by FAA regulations. Regarding the commenter's request for a 6-month compliance time, the FAA notes that since the modification is optional, no compliance deadline is necessary. Operators who wish to resume part 135 overwater operations may complete the modification at their discretion. The FAA did not change this AD as a result of this comment.
Conclusion
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 referenced above. The FAA reviewed the relevant data, considered the comment received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes and the addition of section 6 Final Steps of Guimbal Mandatory Service Bulletin SB 25-006 B, dated December 12, 2025 (Guimbal SB 25-006 B) to the optional terminating action, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Guimbal SB 25-006 B, which specifies procedures for discarding the VHF2 antenna and associated parts from service (if installed), modifying the ELT antenna, which includes relocating the ELT antenna from inside the cockpit to an exterior location, relocating and installing a new VHF2 antenna (if installed), torquing nuts, installing cotter pins, trimming the cowlings, routing the ELT antenna cable, repairing the engine cowl honeycomb, and paint touch-ups.
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.
Differences Between This AD and the MCAI
The MCAI specifies updating the RFM to insert a RFM temporary revision in the limitation section, whereas this AD does not.
The MCAI requires the modification of the ELT to be completed within 6 months, whereas this AD does not.
Costs of Compliance
The FAA estimates that this AD affects 70 helicopters of U.S. registry.
The FAA estimates the following costs to comply with this AD:
Estimated Costs
Action
Labor cost
Parts cost
Cost per
product
Cost on U.S.
operators
Revise RFM
1 work-hour × $85 per hour = $85
$0
$85
$5,950
The FAA estimates the following costs to do the optional modification. The agency has no way of determining the number of helicopters that might need this modification:
Optional Costs
Action
Labor cost
Parts cost
Cost per
product
Modify ELT antenna
3.5 work-hours × $85 per hour = $298
Up to $1,000
Up to $1,298.
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
( printed page 61120)
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:
(2) Will not affect intrastate aviation in Alaska, and
(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.
This airworthiness directive (AD) is effective November 2, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to Hélicoptères Guimbal (HG) Model Cabri G2 helicopters having serial numbers (S/N) 1003 to 1389, except S/N 1383 and 1388, certificated in any category.
(d) Subject
Joint Aircraft System Component (JASC) Code 2562, Emergency locator beacon.
(e) Unsafe Condition
This AD was prompted by a report of a potential malfunction of the helicopter emergency locator transmitter (ELT) and subsequent findings of weak ELT signals on 121.5 MHz and 406 MHz frequencies due to improper antenna installation (location). The FAA is issuing this AD to address the safety risk posed by weak ELT signal transmissions. The unsafe condition, if not addressed, could impair the ability to detect a distress signal during a helicopter emergency, which could delay the arrival of rescue services and timely medical assistance to injured occupants.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Required Actions
Within 30 days after the effective date of this AD, revise the limitations section of the existing rotorcraft flight manual (RFM) for the helicopter by inserting the following text: “For Cabri G2 not equipped with the external ELT antenna: Operations conducted overwater under 14 CFR part 135 are prohibited pursuant to 14 CFR 135.168”.
(1) Inserting a copy of this AD into the limitation section of the RFM satisfies the requirements of paragraph (g) of this AD.
(2) The owner/operator (pilot) holding at least a private pilot certificate may revise the existing RFM for the helicopter and must enter compliance into the helicopter maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.439.
(h) Optional Terminating Action
(1) For internal ELT antenna helicopters, as a terminating action, you may modify the ELT antenna and relocate and install a new VHF2 antenna (if installed) in accordance with section 2 ELT Antenna Installation through section 4 Engine Cowl Honeycomb Repair and section 6 Final Steps of Guimbal Mandatory Service Bulletin SB 25-006 B, dated December 12, 2025 (Guimbal SB 25-006 B), except as provided in paragraphs (h)(1)(i) and (ii) of this AD.
(i) Instead of discarding parts, you must remove those parts from service.
(ii) Where Guimbal SB 25-006 B uses the term check, this AD requires doing an inspection.
(2) Upon completion of paragraph (h)(1) of this AD, revise the RFM by removing the limitation identified in paragraph (g) of this AD.
(i) Alternative Methods of Compliance (AMOCs)
(1) The Manager, International Validation Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the International Validation Branch, send it to the attention of the person identified in paragraph (j) of this AD and email to
AMOC@faa.gov.
(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.
(j) Additional Information
For more information about this AD, contact David Enns, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4147; email:
david.enns@faa.gov.
(k) Material Incorporated by Reference
(1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise.
(i) Guimbal Mandatory Service Bulletin SB 25-006 B, dated December 12, 2025.
(ii) [Reserved]
(3) For Guimbal material identified in this AD, contact Hélicoptères Guimbal, 1070, rue du Lieutenant Parayre, Aérodrome d'Aix-en-Provence, 13290 Les Milles, France; phone: +33-4-42-39-10-88; email:
support@guimbal.com;
website: guimbal.com.
(4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 10101 Hillwood Parkway, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110.
14 CFR part 39
49 U.S.C. 106(g)
www.archives.gov/federal-register/cfr/ibr-locations