# [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 all Diamond Aircraft Industries GmbH (DAI) Model DA 42, DA 42 NG, and DA 42 M-NG airplanes. This proposed AD was prompted by several reports of passenger door separation from the fuselage. This proposed AD would require revising the existing airplane flight manual (AFM) for your airplane to provide the flight crew with revised operating limitations, emergency procedures, and normal operating procedures; modifying the airplane; and repetitively inspecting the door latching and safety hooks for correct engagement, foreign objects, damage (including but not limited to corrosion and wear that exceeds specified limits), and proper function. The FAA is proposing this AD to address the unsafe condition on these products.
**DATES:**
The FAA must receive comments on this NPRM by October 9, 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-2025-2263; 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 Diamond Aircraft material identified in this proposed AD, contact DAI, N.A. Otto-Straβe 5, A-2700 Wiener Neustadt, Austria; phone: +43 2622 26700; email: *[email protected]* ; website: *diamondaircraft.com/* .
• You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. For information on the availability of this material at the FAA, call (817) 222-5110.
**FOR FURTHER INFORMATION CONTACT:**
Evan Weaver, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 944-8910; 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 to an address listed under *ADDRESSES* . Include “Docket No. FAA-2025-2263; Project Identifier MCAI-2024-00729-A” 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 Evan Weaver, 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 European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2024-0235, dated December 6, 2024 (EASA AD 2024-0235) (also referred to as the MCAI), to correct an unsafe condition on all DAI Model DA 42, DA 42 NG, DA 42 M, and DA 42 M-NG airplanes. The MCAI states that DAI received several reports of passenger door separation. DAI attributed the root cause of certain instances to the passenger doors not being properly latched, but DAI was unable to find a definitive root cause of the remaining occurrences. Passenger door separation could damage the airplane, possibly lead to loss of control of the airplane, and injure people on the ground. To address the unsafe condition, DAI issued an AFM temporary revision amending procedures and limitations and issued material with instructions to install placards in the cabin to prevent misuse of the passenger door, to inspect the passenger door latching and safety hook mechanisms, and to collect and report findings after each repetitive inspection to them. The MCAI requires updating the AFM, modifying the airplane, repetitively inspecting the door latching and safety hook mechanisms, and reporting all findings to DAI.
You may examine the MCAI in the AD docket at *regulations.gov* under Docket No. FAA-2025-2263.
**Material Incorporated by Reference Under 1 CFR Part 51**
The FAA reviewed Diamond Aircraft Mandatory Service Bulletin MSB 42-149 and MSB 42NG-095, dated December 2, 2024 (issued as one document), published with Diamond Aircraft Work Instruction WI-MSB 42-149 and WI-MSB 42NG-095, Revision 2, dated January 17, 2025 (issued as one document), attached. This material specifies procedures for installing passenger door placards and inspecting the passenger door system for Model DA 42, DA 42 M, DA 42 NG, and DA 42 M-NG airplanes.
The FAA also reviewed Diamond Aircraft DA 42 AFM Doc. No. 7.01.05-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024. This material specifies procedures for revising the operating limitations, emergency procedures, and normal operating procedures related to door latching and locking for Model DA 42 airplanes with Continental Aerospace Technologies engines installed.
In addition, the FAA reviewed Diamond Aircraft DA 42 with OAM 42-102 Garmin GFC 700 AFM Doc. No. 7.01.06-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024. This material specifies procedures for amending the AFM for Model DA 42 airplanes with Continental Aerospace Technologies engines and Garmin GFC 700 Automatic Flight Control System installed.
The FAA also reviewed Diamond Aircraft DA 42 NG AFM Doc. No. 7.01.15-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024. This material specifies procedures for revising the operating limitations, emergency procedures, and normal operating procedures of the AFM for Model DA 42 NG and DA 42 NG-M airplanes.
The FAA also reviewed Diamond Aircraft DA 42 NG AFM Doc. No. 7.01.16-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024. This material specifies procedures for amending the AFM for Model DA 42 NG and DA 42 NG-M airplanes with MAM 42-600 Performance Enhancement.
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 and material 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 require accomplishing the actions specified in the material already described, except as discussed under “Differences Between this Proposed AD and the MCAI.” The owner/operator (pilot) holding at least a private pilot certificate may revise the existing AFM for your airplane and must enter compliance with the applicable paragraph of this proposed AD into the airplane maintenance records in accordance with 14 CFR 43.9(a) and 14 CFR 91.417(a)(2)(v). The pilot may perform this action because it only involves revising the existing AFM. This action could be performed equally well by a pilot or mechanic. This is an exception to the FAA's standard maintenance regulations.
**Differences Between This Proposed AD and the MCAI**
The MCAI applies to DAI Model 42 M airplanes, but this proposed AD would not include this model because it does not have an FAA type certificate.
The MCAI includes a requirement to inform all flight crews and, thereafter, operate the airplane. However, this AD would not specifically require this action based on the following:
• For the operating limitations: l4 CFR 91.9 requires that no person may operate a civil aircraft without complying 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. Further, compliance with such a requirement in an AD would be impracticable to demonstrate or track on an ongoing basis; therefore, a requirement to operate the airplane in such a manner would be unenforceable.
• For the emergency procedures and normal operating procedures: FAA regulations mandate compliance with only the operating limitations section of the flight manual. The flight manual changes required by this AD apply to the emergency procedures and normal procedures section of the existing AFM for your airplane. Furthermore, compliance with such requirements in an AD is impracticable to demonstrate or track on an ongoing basis; therefore, a requirement to operate the aircraft in such a manner is unenforceable. Nonetheless, the FAA recommends that flight crews of the airplanes listed in the applicability operate in accordance with the revised emergency procedures mandated by this proposed AD.
The service bulletin referred to in the MCAI specifies to contact DAI for repair instructions, but this proposed AD would require contacting the Manager, International Validation Branch, FAA; EASA; or DAI's EASA Design Organization Approval (DOA) instead.
The MCAI specifies where the temporary revisions provide instructions to contact the manufacturer, but this proposed AD would require contacting the Manager, International Validation Branch, FAA; EASA; or DAI's EASA DOA instead.
The MCAI specifies reporting inspection results within 7 days after accomplishing any inspection, but this proposed AD would require reporting inspection results within 30 days after accomplishing any inspection.
**Interim Action**
The FAA considers that this proposed AD would be an interim action. This unsafe condition is still under investigation by the manufacturer and, depending on the results of that investigation, the FAA may consider further rulemaking action.
**Costs of Compliance**
The FAA estimates that this AD, if adopted as proposed, would affect 222 airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed AD:
| Action | Labor cost | Parts cost | Cost per | Cost on U.S. |
| --- | --- | --- | --- | --- |
| AFM revision | 1 work-hour × $85 per hour = $85 | $0 | $85 | $18,870. |
| Initial inspection | 3 work-hours × $85 per hour = $255 | 0 | $255 | $56,610. |
| Repetitive inspections | 1 work-hour × $85 per hour = $85 (each inspection cycle) | 0 | $85 (each inspection cycle) | $18,870 (each inspection cycle). |
| Placard installation | 1 work-hour × $85 per hour = $85 | 25 | $110 | $24,420. |
| Inspection results reporting | 1 work-hour × $85 per hour = $85 (each cycle) | 0 | $85 (each cycle) | $18,870 (each cycle). |
The FAA estimates the following costs to do any necessary replacements that would be required based on the results of the proposed inspections. The agency has no way of determining the number of airplanes that might need these replacements:
| Action | Labor cost | Parts cost | Cost per |
| --- | --- | --- | --- |
| Safety hook replacement | 1 work-hour × $85 per hour = $85 | $306 | $391 |
| Safety hook spring replacement | 1 work-hour × $85 per hour = $85 | 8 | 93 |
| Retaining bracket replacement | 1 work-hour × $85 per hour = $85 | 185 | 270 |
| Safety hook actuation pin replacement | 1 work-hour × $85 per hour = $85 | 164 | 249 |
| Latching mechanism spring replacement | 1 work-hour × $85 per hour = $85 | 12 | 97 |
| Latching bolts replacement | 1 work-hour × $85 per hour = $85 | 109 | 194 |
| Gas spring replacement | 1 work-hour × $85 per hour = $85 | 312 | 397 |
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.
**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 current 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 take 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**
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:
*Diamond Aircraft Industries GmbH:* Docket No. FAA-2025-2263; Project Identifier MCAI-2024-00729-A.
**(a) Comments Due Date**
The FAA must receive comments on this airworthiness directive (AD) by October 9, 2025.
**(b) Affected ADs**
None.
**(c) Applicability**
This AD applies to all Diamond Aircraft Industries GmbH (DAI) Model DA 42, DA 42 NG, and DA 42 M-NG airplanes, certificated in any category.
**(d) Subject**
Joint Aircraft System Component (JASC) Code 5210, Passenger/Crew Doors.
**(e) Unsafe Condition**
This AD was prompted several reports of passenger door separation from the fuselage. The FAA is issuing this AD to address this unsafe condition. The unsafe condition, if not addressed, could result in damage to the aircraft, loss of control of the aircraft, injuries to persons, and damage to property on the ground.
**(f) Definition**
For the purposes of this AD, “the Diamond Aircraft work instruction” is defined as Diamond Aircraft Work Instruction WI-MSB 42-149 and WI-MSB 42NG-095, Revision 2, dated January 17, 2025 (issued as one document), attached to Diamond Aircraft Mandatory Service Bulletin MSB 42-149 and MSB 42NG-095, dated December 2, 2024 (issued as one document).
**(g) Applicable AFM Temporary Revisions**
(1) For Model DA 42 airplanes without OAM 42-102: Diamond Aircraft DA 42 Airplane Flight Manual (AFM) Doc. No. 7.01.05-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024.
(2) For Model DA 42 airplanes with OAM 42-102, Garmin GFC 700: Diamond Aircraft DA 42 with OAM 42-102 Garmin GFC 700 AFM Doc. No. 7.01.06-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024.
(3) For Model DA 42 NG and DA 42 NG-M airplanes without MAM 42-600 Performance Enhancement: Diamond Aircraft DA 42 NG AFM Doc. No. 7.01.15-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024.
(4) For Model DA 42 NG and DA 42 NG-M airplanes with MAM 42-600 Performance Enhancement: Diamond Aircraft DA 42 NG AFM Doc. No. 7.01.16-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024.
**(h) Compliance**
Comply with this AD within the compliance times specified, unless already done.
**(i) Required Actions**
(1) Within 50 hours time-in-service (TIS) or 50 days, whichever occurs first after the effective date of this AD, revise the existing AFM for your airplane to include the information specified in the applicable AFM temporary revision specified in paragraphs (g)(1) through (4) of this AD appropriate for your airplane model.
(i) The owner/operator (pilot) holding at least a private pilot certificate may revise the existing AFM for your airplane and must enter compliance with the applicable paragraph of this AD into the airplane 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 91.147, 121.380, or 135.439.
(ii) The AFM revision required by paragraph (i)(1) of this AD may be accomplished before the initial inspection and modification required by paragraph (i)(2) of this AD for that airplane.
(2) Within 50 hours TIS or 50 days, whichever occurs first after the effective date of this AD, accomplish the initial inspection of the safety hook, safety hook spring, retaining bracket, safety hook actuation pin, latching mechanism spring, latching bolts, and gas spring and the modification of the airplane with placards in accordance with the instructions of Section III, steps 2 through 4, 6, 7, 9 through 11, 13, 14, 16, 18, 19, 21 through 23, and 25 through 36 in the Diamond Aircraft work instruction specified in paragraph (f) of this AD.
(3) Within 200 hours TIS or 12 months, whichever occurs first after the initial inspection required by paragraph (i)(2) of this AD, and thereafter at intervals not to exceed 210 hours TIS or 13 months, whichever occurs first, accomplish the repetitive inspections of the airplane in accordance with the instructions of Section IV, steps 2 through 6, of the Diamond Aircraft work instruction specified in paragraph (f) of this AD.
(4) If, during any inspection as required by paragraph (i)(2) or (3) of this AD, any findings, as defined in Section III, steps 2 through 4, 6, 7, 9 through 11, 13, 14, 16, 18, 19, 21 through 23, and 25 through 36, and Section IV, steps 2 through 5, of the Diamond Aircraft work instruction is identified, before further flight, accomplish the applicable corrective action(s) in accordance with the instructions of Section III, steps 2 through 4, 6, 7, 9 through 11, 13, 14, 16, 18, 19, 21 through 23, and 25 through 36, and Section IV, steps 2 through 5, of the Diamond Aircraft work instruction specified in paragraph (f) of this AD. Where instructed to contact the manufacturer “in case of doubt” or for approved instructions, this AD requires before further flight using instructions approved by the Manager, International Validation Branch, FAA; the European Union Aviation Safety Agency (EASA); or DAI's EASA Design Organization Approval (DOA) and within the compliance time specified therein, accomplishing those instructions. If approved by the DOA, the approval must include the DOA-authorized signature.
**(j) Reporting**
(1) Within 30 days after performing the initial inspection required by paragraph (i)(2) of this AD or within 30 days after the effective date of this AD, whichever occurs later, report the results of the initial inspection, including no findings, to DAI. The report must include the information specified in Appendix B of the Diamond Aircraft work instruction specified in paragraph (f) of this AD.
(2) Report the results of each repetitive inspection required by paragraph (i)(3) of this AD, including no findings, to DAI within 30 days after that inspection. The report must include the information specified in Appendix B of the Diamond Aircraft work instruction specified in paragraph (f) of this AD.
**(k) Credit for Previous Actions**
You may take credit for the actions required by paragraph (i) of this AD if you performed those actions before the effective date of this AD using Diamond Aircraft Mandatory Service Bulletin MSB 42-149 and MSB 42NG-095, dated December 2, 2024 (issued as one document), published with Diamond Aircraft Work Instructions WI-MSB 42-149 and WI-MSB 42NG-095, Revision 1, dated December 5, 2024 (issued as one document), attached.
**(l) 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 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 (m) 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 local flight standards district office/certificate holding district office.
**(m) Additional Information**
For more information about this AD, contact Evan Weaver, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 944-8910; email: *[email protected].*
**(n) 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) Diamond Aircraft Mandatory Service Bulletin MSB 42-149 and MSB 42NG-095, dated December 2, 2024 (issued as one document), published with Diamond Aircraft Work Instruction WI-MSB 42-149 and WI-MSB 42NG-095, Revision 2, dated January 17, 2025 (issued as one document), attached.
(ii) Diamond Aircraft DA 42 Aircraft Flight Manual (AFM) Doc. No. 7.01.05-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024.
(iii) Diamond Aircraft DA 42 with OAM 42-102 Garmin GFC 700 AFM Doc. No. 7.01.06-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024.
(iv) Diamond Aircraft DA 42 NG AFM Doc. No. 7.01.15-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024.
(v) Diamond Aircraft DA 42 NG AFM Doc. No. 7.01.16-E Temporary Revision TR-MAM-42-1333, Door Latching and Locking, dated November 28, 2024.
(3) For Diamond Aircraft material identified in this AD, contact Diamond Aircraft Industries GmbH, N.A. Otto-Straβe 5, A-2700 Wiener Neustadt, Austria; phone: +43 2622 26700; email: *[email protected];* website: *diamondaircraft.com/* .
(4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. 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 *[email protected].*
Issued on August 20, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.