SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments using a method listed under ADDRESSES . Include “Docket No. FAA-2026-8796; Project Identifier AD-2026-00018-R” at the beginning of your ( printed page 57520) comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may revise this proposal 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 NPRM.

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 NPRM 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 NPRM, 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 NPRM. Submissions containing CBI should be sent to James Guo, Aviation Safety Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712. 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 received a report of an event involving a Model 206L helicopter with Van Horn Aviation main rotor blades, part number 20633000-101. These blades were approved for installation through FAA STC SR02684LA.

During this event, the helicopter experienced an unexpected moderate-to-severe vertical vibration during flight. Due to the unexpected vibration, the pilot initially lowered the collective to begin a descent. Subsequently, when the pilot raised the collective and initiated a left turn, the vibration diminished. The pilot was able to complete a landing without further incident; however, post-flight inspection revealed that the helicopter had sustained tail boom damage. Due to this event, the manufacturer issued material that includes accomplishing existing maintenance actions that may help reduce the likelihood of this unsafe condition. The root cause for the vibration is still being investigated. Due to risk analysis based on historical events and ongoing investigation, the FAA has determined that this proposed interim AD is necessary to mitigate risk. This condition, if not addressed, could result in structural damage to the aircraft and loss of control of the helicopter.

FAA's Determination

The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed Van Horn Aviation, L.L.C. Rotorcraft Flight Manual Supplement, Document No. 206L-MR-FMS-101, Revision 0, dated March 25, 2026 (VHA RFMS). This material specifies procedures to accomplish in the event of an unexpected moderate-to-severe vibration during flight. 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.

Proposed AD Requirements in This NPRM

This proposed AD would require revising the existing RFM for the helicopter to include revising the Limitations section to include a text stating a V_NE limitation based on gross weight. This proposed AD would also require revising the existing RFM for the helicopter by incorporating the VHA RFMS.

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 pilot may perform this action because it only involves revising the RFM, which could be performed equally well by a pilot or a mechanic. This is an exception to the FAA's standard maintenance regulations.

Differences Between This Proposed AD and the Referenced Material

Where the material in Section 1, “Limitations,” of the VHA RFMS specifies “No Limitations,” this proposed AD would require revising the RFM to also include a V_NE limitation based on gross weight. Due to risk analysis based on historical events and ongoing investigation, the FAA has determined that this V_NE limitation is necessary to mitigate risk.

Interim Action

The FAA considers that this proposed AD would be an interim action. If further action is later identified, the FAA might consider further rulemaking.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 200 helicopters of U.S. registry.

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

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 ( printed page 57521) that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 this proposed regulation:

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

(2) Would not affect intrastate aviation in Alaska, and

(3) Would not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

The Proposed Amendment

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

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

Bell Textron Canada Limited: Docket No. FAA-2026-8796; Project Identifier AD-2026-00018-R.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by October 26, 2026.

(b) Affected ADs

None.

(c) Applicability

This AD applies to all Bell Textron Canada Limited Model 206L, 206L-1, 206L-3, and 206L-4 helicopters, certificated in any category, with FAA Supplemental Type Certificate (STC) SR02684LA installed.

(d) Subject

Joint Aircraft System Component (JASC) Code 6210, Main Rotor Blades.

(e) Unsafe Condition

This AD was prompted by an event where an affected helicopter with FAA STC SR02684LA installed experienced moderate to severe vertical vibration which resulted in damage to the tail boom of the helicopter. The FAA is issuing this AD to prevent excessive vibration which may result in structural failure. The unsafe condition, if not addressed, could result in structural damage to the aircraft and loss of control of the helicopter.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Required Actions

(1) Within 30 days after the effective date of this AD revise the existing rotorcraft flight manual (RFM) for the helicopter by accomplishing the following:

(i) Insert the Van Horn Aviation, L.L.C. Rotorcraft Flight Manual Supplement, Document No. 206L-MR-FMS-101, Revision 0, dated March 25, 2026.

(ii) In the Limitations section of the RFM, insert the following text with pen and ink: “V_NE is 85 KIAS (98 MPH) when Gross Weight is 3400 lb or below, or placarded V_NE, whichever is less”.

(2) The owner/operator (pilot) holding at least a private pilot certificate may revise the existing Rotorcraft Flight Manual for the helicopter as required by paragraphs (g)(1)(i) and (ii) and must enter compliance with this requirement into the helicopter maintenance records in accordance with 14 CFR 43.9(a) and 14 CFR 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.439.

(h) Special Flight Permits

Special flight permits may be issued in accordance with 14 CFR 21.197 and 21.199, provided the flight is restricted to a speed of no greater than 85 KIAS while the Gross Weight is less than 3400 lbs.

(i) Alternative Methods of Compliance (AMOCs)

(1) The Manager, West Certification 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 West Certification 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 James Guo, Aviation Safety Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone: (562) 627-5357; email: WCB-COS@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) Van Horn Aviation, L.L.C. Rotorcraft Flight Manual Supplement, Document No. 206L-MR-FMS-101, Revision 0, dated March 25, 2026.

(ii) [Reserved]

(3) For Van Horn Aviation, L.L.C. material identified in this AD contact Van Horn Aviation, LLC, 1510 West Drake Drive, Tempe, AZ 85283; phone: (480) 483-4202; email: info@vanhornaviation.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.

(5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/​federal-register/​cfr/​ibr-locations or email fr.inspection@nara.gov.

91 FR 57519