# [Amended]
**AGENCY:**
Federal Aviation Administration (FAA), DOT.
**ACTION:**
Notice of proposed rulemaking (NPRM).
**SUMMARY:**
The FAA proposes to adopt a new airworthiness directive (AD) for certain Dassault Aviation Model FALCON 2000EX airplanes. This proposed AD was prompted by a report of simultaneous failures of the main DC buses powered by Generator 1 (GEN1), and Generator 2 (GEN2) after flap extension during approach. This proposed AD would require revising the existing airplane flight manual (AFM). The FAA is proposing this AD to address the unsafe condition on these products.
**DATES:**
The FAA must receive comments on this proposed AD by November 10, 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-2025-2553; 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; telephone +49 221 8999 000; email *[email protected]* . You may find this material on the EASA website at *ad.easa.europa.eu* . It is also available at *regulations.gov* under Docket No. FAA-2025-2553.
• You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195.
**FOR FURTHER INFORMATION CONTACT:**
Steven Dzierzynski, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7367; email: *[email protected]* .
**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 the *ADDRESSES* section. Include “Docket No. FAA-2025-2553; Project Identifier MCAI-2025-00186-T” 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 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 Steven Dzierzynski, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7367; email: *[email protected]* . Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.
**Background**
EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2025-0042, dated February 19, 2025 (EASA AD 2025-0042) (also referred to as the MCAI), to correct an unsafe condition for certain Dassault Aviation Model FALCON 2000EX airplanes. The MCAI states there was a report of simultaneous failures of the main DC buses powered by GEN1 and GEN2 after flap extension during approach. This event resulted in intermittent crew alerting system (CAS) messages, including the red CAS message “2 GEN'S FAIL,” data flickering on the display units, and flashing lights on the overhead panel, which led to the loss of the main DC buses after a short period.
The FAA is issuing this AD to address intermittent and flickering data, as well as CAS messages. The unsafe condition, if not addressed, could lead to increased pilot workload, possibly during a critical phase of flight. You may examine the MCAI in the AD docket at *regulations.gov* under Docket No. FAA-2025-2553.
**Material Incorporated by Reference Under 1 CFR Part 51**
EASA AD 2025-0042 specifies procedures for revising the AFM to provide flightcrew with emergency procedures to address intermittent and flickering data and CAS messages.
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 referenced above. The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop in other products of the same type design.
**Proposed AD Requirements in This NPRM**
This proposed AD would be accomplishing the actions specified in EASA AD 2025-0042 described previously, except for any differences identified as exceptions in the regulatory text of this proposed AD.
**Compliance With AFM Revisions**
EASA AD 2025-0042 requires operators to “inform all flight crews, and, thereafter, operate the airplane accordingly.” However, this proposed AD would not specifically require those actions as those actions are already required by FAA regulations. FAA regulations require that operators furnish to pilots any changes to the AFM (for example, 14 CFR 121.137), and to ensure the pilots are familiar with the AFM (for example, 14 CFR 91.505). As with any other flightcrew training requirement, training on the updated AFM content is tracked by the operators and recorded in each pilot's training record, which is available for the FAA to review. FAA regulations also require pilots to follow the procedures in the existing AFM including all updates. 14 CFR 91.9 requires that any person operating a civil aircraft must comply with the operating limitations specified in the AFM. Therefore, including a requirement in this proposed AD to operate the airplane according to the revised AFM would be redundant and unnecessary.
**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 2025-0042 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2025-0042 through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Using common terms that are the same as the heading of a particular section in EASA AD 2025-0042 does not mean that operators need comply only with that section. For example, where the AD requirement refers to “all required actions and compliance times,” compliance with this AD requirement is not limited to the section titled “Required Action(s) and Compliance Time(s)” in EASA AD 2025-0042. Material required by EASA AD 2025-0042 for compliance will be available at *regulations.gov* by searching for and locating Docket No. FAA-2025-2553 after the FAA final rule is published.
**Costs of Compliance**
The FAA estimates that this AD, if adopted as proposed, would affect 304 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:
| Labor cost | Parts cost | Cost per | Cost on U.S. |
| --- | --- | --- | --- |
| 1 work-hour × $85 per hour = $85 | $0 | $85 | $25,840 |
**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 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.
**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:
**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
2. The FAA amends § 39.13 by adding the following new airworthiness directive:
*Dassault Aviation:* Docket No. FAA-2025-2553; Project Identifier MCAI-2025-00186-T.
**(a) Comments Due Date**
The FAA must receive comments on this airworthiness directive (AD) by November 10, 2025.
**(b) Affected ADs**
None.
**(c) Applicability**
This AD applies to Dassault Aviation Model FALCON 2000EX airplanes, certificated in any category, as identified in European Union Aviation Safety Agency (EASA) AD 2025-0042, dated February 19, 2025 (EASA AD 2025-0042).
**(d) Subject**
Air Transport Association (ATA) of America Code 24, Electrical Power.
**(e) Unsafe Condition**
This AD was prompted by a report of simultaneous failures of the main DC buses powered by Generator 1 (GEN1), and Generator 2 (GEN2) after flap extension during approach, which initially resulted in intermittent display of crew alerting system (CAS) messages, and led to the loss of the main DC buses. The FAA is issuing this AD to address intermittent and flickering data, as well as CAS messages. The unsafe condition, if not addressed, could lead to increased pilot workload, possibly during a critical phase of flight.
**(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 EASA AD 2025-0042.
**(h) Exceptions to EASA AD 2025-0042**
(1) Where paragraph (1) of EASA AD 2025-0042 specifies to “inform all flight crews and, thereafter, operate the airplane accordingly,” this AD does not require those actions as those actions are already required by existing FAA operating regulations (see 14 CFR 91.9, 14 CFR 91.505, and 14 CFR 121.137).
(2) Where EASA AD 2025-0042 refers to its effective date, this AD requires using the effective date of this AD.
(3) This AD does not adopt the “Remarks” section of EASA AD 2025-0042.
**(i) Additional AD Provisions**
The following provisions also apply to this AD:
(1) *Alternative Methods of Compliance (AMOCs):* 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 responsible Flight Standards 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: *[email protected]* . Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office.
(2) *Contacting the Manufacturer:* For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, International Validation Branch, FAA; or EASA; or Dassault Aviation's EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.
**(j) Additional Information**
For more information about this AD, contact Steven Dzierzynski, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7367; email: *[email protected].*
**(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 this AD specifies otherwise.
(i) European Union Aviation Safety Agency (EASA) AD 2025-0042, dated February 19, 2025.
(ii) Reserved.
(3) For EASA material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999 000; email *[email protected];* website *easa.europa.eu.* You may find this material on the EASA website at *ad.easa.europa.eu.*
(4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195.
(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 *[email protected].*
Issued on September 23, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.