90 FR 117 pgs. 26225-26228 - Airworthiness Directives; Airbus Helicopters
Type: PRORULEVolume: 90Number: 117Pages: 26225 - 26228
Pages: 26225, 26226, 26227, 26228Docket number: [Docket No. FAA-2025-1108; Project Identifier MCAI-2025-00428-R]
FR document: [FR Doc. 2025-11339 Filed 6-18-25; 8:45 am]
Agency: Transportation Department
Sub Agency: Federal Aviation Administration
Official PDF Version: PDF Version
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-1108; Project Identifier MCAI-2025-00428-R]
RIN 2120-AA64
Airworthiness Directives; Airbus Helicopters
AGENCY:
Federal Aviation Administration (FAA), DOT.
ACTION:
Notice of proposed rulemaking (NPRM).
SUMMARY:
[top] The FAA proposes to supersede Airworthiness Directive (AD) 2020-24-07, which applies to certain Airbus Helicopters Model AS350B3, EC130B4, and EC130T2 helicopters. AD 2020-24-07 requires modifying and inspecting the pilot's and co-pilot's throttle twist grip (twist grip) for proper operation. Since the FAA issued AD 2020-24-07, Airbus Helicopters developed another modification of the twist grip and additional corrective actions for helicopters already modified. This proposed AD was prompted by reports of the engine remaining in idle when the twist grip was turned from the "IDLE" mode to the "FLIGHT" mode. This proposed AD would retain the actions required by AD 2020-24-07 and mandate an additional modification, which would constitute terminating action for the repetitive inspections.
DATES:
The FAA must receive comments on this NPRM by August 4, 2025.
ADDRESSES:
You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:
• Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.
• Fax: (202) 493-2251.
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2025-1108; 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 NPRM, the mandatory continuing airworthiness information (MCAI) any comments received, and other information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
• For European Union Aviation Safety Agency (EASA) material identified in this proposed AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: ADs@easa.europa.eu; website: easa.europa.eu. You may find this material on the EASA website at ad.easa.europa.eu.
• You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110. It is also available at regulations.gov under Docket No. FAA-2025-1108.
FOR FURTHER INFORMATION CONTACT:
Zain Jamal, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (847) 294-7264; email: zain.jamal@faa.gov .
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include "Docket No. FAA-2025-1108; Project Identifier MCAI-2025-00428-R" at the beginning of your 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 amend the 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 Zain Jamal, 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 AD 2020-24-07, Amendment 39-21337 (85 FR 78954, December 8, 2020) (AD 2020-24-07), for Airbus Helicopters Model AS350B3 helicopters with an ARRIEL 2B1 engine with the two-channel Full Authority Digital Engine Control (FADEC) and with new twist grip modification (MOD) 073254 or with an ARRIEL 2D engine installed; Model EC130B4 helicopters with an ARRIEL 2B1 engine with the two-channel FADEC and with new twist grip MOD 073773 installed; and Model EC130T2 helicopters with an ARRIEL 2D engine installed. AD 2020-24-07 was prompted by MCAI originated by EASA, which is the Technical Agent for the Member States of the European Union. EASA issued EASA AD 2017-0059, dated April 6, 2017 (EASA AD 2017-0059), to correct an unsafe condition identified, as the microswitches in the engine "IDLE"/"FLIGHT" control system could be affected by the corrosive effects of a salt-laden atmosphere.
AD 2020-24-07 requires repetitively inspecting the wiring, performing an insulation test, inspecting the pilot and copilot twist grip controls, and testing the pilot and copilot twist grip controls for proper functioning. The FAA issued AD 2020-24-07 to prevent the failure of one of the microswitches, 53Ka, 53Kb, or 65K, which can prevent switching from "IDLE" mode to "FLIGHT" mode during autorotation training making it impossible to recover from a practice autorotation and compelling the pilot to continue the autorotation to the ground. This condition could result in unintended touchdown to the ground at a flight-idle power setting during a practice autorotation, damage to the helicopter, and injury to occupants.
Actions Since AD 2020-24-07 Was Issued
[top] Since the FAA issued AD 2020-24-07, EASA superseded AD 2017-0059 and issued EASA AD 2023-0133, dated July 5, 2023 (EASA AD 2023-0133). EASA AD 2023-0133 states that Airbus Helicopters developed MOD 074782, introducing a new engine power control assembly with microswitches 53Ka, 53Kb and 65K, and mandating installation of a serviceable assembly, while prohibiting installation of an affected microswitch on any helicopter. EASA AD 2023-0133 also expands the applicability to all serial numbers of Airbus Helicopters Model AS 350 B3, EC 130 B4, and EC 130 T2 helicopters. EASA then superseded AD 2023-0133 and issued EASA AD 2023-0187, dated October 27, 2023 (EASA AD 2023-0187). EASA AD 2023-0187 states that errors were found in the modification installation procedure and requires amending the modification instructions and additional work for certain helicopters already modified. EASA then superseded AD 2023-0187 and issued EASA AD 2023-0187R1, dated March 20, 2025 (EASA AD 2023-0187R1) (also referred to as the MCAI), to correct an unsafe condition for all Airbus Helicopters Model AS 350 B3, EC 130 B4, and EC 130 T2 helicopters. The MCAI states that the salt-laden atmospheric condition definition should be re-formulated, adjusting to the less
You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-1108.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed EASA AD 2023-0187R1, which specifies procedures for modifying the twist grip operational logic on helicopters with MOD 074263 installed. EASA AD 2023-0187R1 also specifies procedures for repetitively inspecting for no marks, residue, or corrosion and testing the "IDLE" and "FLIGHT" controls on the pilot's and copilot's twist grips on helicopters with MOD 074699 installed. Additionally, EASA AD 2023-0187R1, specifies procedures for installing MOD 074782 on helicopters if an affected microswitch is installed, which would constitute terminating action for the repetitive inspections. For those helicopters with MOD 074782 installed, EASA AD 2023-0187R1 specifies accomplishing a one-time inspection of the installation of the microswitch assembly of the engine power control. EASA AD 2023-0187R1 also prohibits installing a microswitch having a part number (P/N) T3933-3 or a twist grip containing a microswitch P/N T3933-3 on any helicopter.
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 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, it has notified the FAA of the unsafe condition described in the MCAI referenced above. 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.
Proposed AD Requirements in This NPRM
This proposed AD would retain all the requirements of AD 2020-24-07. This proposed AD would require installing new microswitches. This proposed AD would also require accomplishing the actions specified in the material already described, except for any differences identified as exceptions in the regulatory text of this proposed AD. See "Differences Between this Proposed AD and the MCAI" for a discussion of the general differences included in this AD.
Explanation of Required Compliance Information
In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, the FAA proposes to incorporate EASA AD 2023-0187R1 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2023-0187R1 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Material referenced in EASA AD 2023-0187R1 for compliance will be available at regulations.gov under Docket No. FAA-2025-1108 after the FAA final rule is published.
Differences Between This Proposed AD and the MCAI
EASA AD 2023-0187R1 specifies the initial inspections within 10 flight hours or 7 days; this AD requires compliance before the next autorotation training flight, 100 hours time-in-service, or 6 months, whichever occurs first, as the unsafe condition only occurs when transitioning the throttle in-flight from flight to idle and back to flight, such as during a practice autorotation. Additionally, EASA AD 2023-0187R1 specifies installing Airbus Helicopters MOD 074263; this proposed AD would not require the modification as it would not correct the unsafe condition.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 856 helicopters of U.S. registry. Labor costs are estimated at $85 per hour. Based on these numbers, the FAA estimates the following costs to comply with this proposed AD.
Inspecting the wiring, performing an insulation test, inspecting the pilot and copilot twist grip controls, and testing the pilot and copilot twist grip controls required by MOD 074699 would take about 4 work-hours, for an estimated cost of $340 per helicopter and $291,040 for the U.S. fleet. Installing MOD 074782 would take about 4 work-hours, for an estimated cost of $340 per helicopter.
The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected operators.
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
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 that the 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:
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PART 39-AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority:
49 U.S.C. 106(g), 40113, 44701.
§?39.13 [Amended]
2. The FAA amends §?39.13 by:
a. Removing Airworthiness Directive 2020-24-07, Amendment 39-21337 (20 FR 19121, December 8, 2020); and
b. Adding the following new airworthiness directive:
Airbus Helicopters: Docket No. FAA-2025-1108; Project Identifier MCAI-2025-00428-R.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive (AD) by August 4, 2025.
(b) Affected ADs
This AD replaces AD 2020-24-07, Amendment 39-21337 (20 FR 19121, December 8, 2020).
(c) Applicability
This AD applies to Airbus Helicopters Model AS350B3, EC130B4, and EC130T2 helicopters, certificated in any category.
(d) Subject
Joint Aircraft System Component (JASC) Code 7600, Engine Controls.
(e) Unsafe Condition
This AD was prompted by reports of the of the engine remaining in idle when the throttle twist grip was turned from the "IDLE" mode to the "FLIGHT" mode. The FAA is issuing this AD to correct the failure of one of the microswitches, 53Ka, 53Kb, or 65K which can prevent the pilot from switching from "IDLE" mode to "FLIGHT" mode during autorotation training making it impossible to recover from a practice autorotation and compelling the pilot to continue the autorotation to the ground. This condition could result in unintended touchdown to the ground at a flight-idle power setting during a practice autorotation, damage to the helicopter, and injury to occupants.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Requirements
Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in and in accordance with European Union Aviation Safety Agency AD 2023-0187R1, dated March 20, 2025 (EASA AD 2023-0187R1).
(h) Exceptions to EASA AD 2023-0187R1
(1) Where EASA AD 2023-0187R1 refers to its effective date, November 10, 2023 (the effective date of EASA AD 2023-0187, dated October 27, 2023), or July 19, 2023 (the effective date of EASA AD 2023-0133, dated July 5, 2023), this AD requires using the effective date of this AD.
(2) Where EASA AD 2023-0187R1 refers to April 13, 2017 (the effective date of EASA AD 2017-0059, dated April 6, 2017), this AD requires using January 30, 2019 (the effective date of AD 2018-26-02, Amendment 39-19532 (83 FR 66093, December 26, 2018)).
(3) Where EASA AD 2023-0187R1 refer to flight hours (FH), this AD requires using hours time-in-service.
(4) This AD does not adopt paragraphs (1) and (2) of EASA AD 2023-0187R1.
(5) Instead of complying with the compliance times in Table 1 in paragraph (3) of EASA AD 2023-0187R1, this AD requires the helicopters identified under the Helicopters in Pre-MOD 074699 Configuration column to accomplish the actions required by paragraph (3) of EASA AD 2023-0187R1 before the next practice autorotation, within 100 hours time-in-service, or 6 months after January 12, 2021 (the effective date of AD 2020-24-07), whichever occurs first.
(6) Where Table 2 in paragraph (4), Table 3 in paragraph (7), and Table 4 in paragraph (9) of EASA AD 2023-0187R1 states "For helicopters which operate or have operated in salt-laden atmospheric conditions," this AD requires replacing that text with "For helicopters which operate or have operated in salt-laden atmospheric conditions, or if it cannot be determined if a helicopter has been operated in salt-laden atmospheric conditions."
(7) Where paragraph (6) of EASA AD 2023-0187R1 states "discrepancies are detected," this AD requires replacing that text with "marks, residue, corrosion, flaky varnish are detected; the values of the insulation test are less than 10 megaOhms; the microswitch closes in the "IDLE" position and does not open as soon as the twist grip is turned to the "FLIGHT" position; or the microswitch is open in the "FLIGHT" position and does not close as soon as the twist grip is turned to the "IDLE" position".
(8) Where paragraph (9) of EASA AD 2023-0187R1 states "any discrepancy," for purposes of this AD, discrepancy is defined as a nut torque that is outside allowable torque limits, or clearance between the support plate assembly and the washers that is not within 01.mm to 0.3 mm.
(9) This AD does not adopt the "Remarks" section of EASA AD 2023-0187R1.
(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) Related Information
For more information about this AD, contact Zain Jamal, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (847) 294-7264; email: zain.jamal@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) European Union Aviation Safety Agency (EASA) AD 2023-0187R1, dated March 20, 2025.
(ii) [Reserved]
(3) For EASA material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: ADs@easa.europa.eu; website: easa.europa.eu. You may find this EASA material on the EASA website at ad.easa.europa.eu.
(4) You may view this material at FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-321, 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 .
Issued on June 16, 2025.
Paul R. Bernado,
Acting Director, Compliance & Airworthiness Division, Aircraft Certification Service.
[FR Doc. 2025-11339 Filed 6-18-25; 8:45 am]
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