Airworthiness Directives; Diamond Aircraft Industries Inc. Airplanes

[Federal Register Volume 91, Number 58 (Thursday, March 26, 2026)]
[Rules and Regulations]
[Pages 14643-14645]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-05883]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-5397; Project Identifier MCAI-2025-00972-A; 
Amendment 39-23291; AD 2026-06-03]
RIN 2120-AA64


Airworthiness Directives; Diamond Aircraft Industries Inc. 
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2020-14-
06, which applied to all Diamond Aircraft Industries Inc. (DAI) Model 
DA 40, DA 40 F, and DA 40 NG airplanes. AD 2020-14-06 required 
replacing affected parts, inspecting the fuel tank chambers, and 
removing rubber material that has detached from the fuel tank 
connection hoses. AD 2020-14-06 also prohibited installing an affected 
part on any airplane. Since the FAA issued AD 2020-14-06, additional 
affected parts installed during production on Model DA 40 NG airplanes 
have been reported. As a result, the manufacturer has published updated 
service material for the Model DA 40 NG. This AD requires the same 
actions as AD 2020-14-06 and requires updated service material to be 
used for the Model DA 40 NG airplanes. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective April 30, 2026.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of April 30, 
2026.
    The Director of the Federal Register approved the incorporation by 
reference of certain other publications listed in this AD as of August 
4, 2020 (85 FR 42687, July 15, 2020).

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2025-5397; 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:
    <bullet> For Diamond Aircraft Industries material identified in 
this AD, contact DAI, 1560 Crumlin Sideroad, London, Ontario, Canada, 
N5V 1S2; phone: (519) 457-4041, fax: (519) 457-4045; email: [email protected].
    <bullet> 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. It is also available at regulations.gov under 
Docket No. FAA-2025-5397.

FOR FURTHER INFORMATION CONTACT: Joseph Catanzaro, Aviation Safety 
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
phone: (516) 228-7366; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2020-14-06, Amendment 39-21160 (85 FR 
42687, July 15, 2020), (AD 2020-14-06). AD 2020-14-06 applied to DAI 
Model DA 40, DA 40 F, and DA 40 NG airplanes (including Model DA 40 NG 
airplanes that have been converted from the Model DA 40 D). AD 2020-14-
06 required replacing affected parts, inspecting the fuel tank 
chambers, and removing rubber material that has detached from the fuel 
tank connection hoses. AD 2020-14-06 also prohibited installing an 
affected part on any airplane. The FAA issued AD 2020-14-06 to detect 
and prevent fuel starvation and reduced control of the airplane. AD 
2020-14-16 was prompted by Transport Canada CF-2019-39, dated October 
31, 2019 (Transport Canada AD CF-2019-39) issued by Transport Canada, 
which is the aviation authority for Canada.
    The NPRM was published in the Federal Register on December 23, 2025 
(90 FR 60031). The NPRM was prompted by Transport Canada AD CF-2019-
39R1, dated May 21, 2025 (also referred to as the MCAI), which 
superseded Transport Canada AD CF-2019-39 based on reports of 
additional affected parts installed during production on DAI Model DA 
40 NG airplanes. As a result, the manufacturer published updated 
service material for the Model DA 40 NG. The MCAI also continues to 
require replacing affected fuel tank connection hoses, inspecting the 
fuel tank chambers, and removing rubber material that has detached from 
the fuel tank connection hoses.
    In the NPRM, the FAA proposed to require the same actions as AD 
2020-14-06 and to require updated service material to be used for the 
Model DA 40 NG airplanes.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2025-5397.

Discussion of Final Airworthiness Directive

Comments

    The FAA received no comments on the NPRM or on the determination of 
the costs.

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 any comments 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 any other changes described previously, 
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 Diamond Aircraft Industries Mandatory Service 
Bulletin

[[Page 14644]]

No. MSB 40NG-064 Rev. 3, dated January 23, 2025, which specifies 
procedures for replacing affected parts, inspecting the fuel tank 
chambers, and removing rubber material that has detached from the 
hoses. This material also specifies the service centers from which the 
affected parts could have been obtained and the serial numbers for 
additional DAI Model DA 40 NG airplanes that are affected by the unsafe 
condition and were not in the previous version of the material.
    This AD also requires the following Diamond Aircraft Industries 
Mandatory Service Bulletins, which the Director of the Federal Register 
approved for incorporation by reference as of August 4, 2020 (85 FR 
42687, July 15, 2020):
    <bullet> Diamond Aircraft Industries Mandatory Service Bulletin No. 
MSB 40-087, Revision 3, dated November 5, 2019.
    <bullet> Diamond Aircraft Industries Mandatory Service Bulletin No. 
MSB F4-037, Revision 3, dated November 5, 2019.
    <bullet> Diamond Aircraft Industries Work Instruction WI-MSB 40-
087, Revision 0, dated July 1, 2019.
    <bullet> Diamond Aircraft Industries Work Instruction WI-MSB F4-
037, Revision 0, dated July 1, 2019.
    <bullet> Diamond Aircraft Industries Work Instruction WI-MSB 40 NG-
064, Revision 0, dated July 1, 2019.
    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.

Costs of Compliance

    The FAA estimates that this AD affects 987 airplanes of U.S. 
registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                       Cost per    Cost on U.S.
                  Action                            Labor cost           Parts cost    product       operators
----------------------------------------------------------------------------------------------------------------
Inspect the fuel tank chambers...........  1 work-hour x $85 per hour            $0          $85         $83,895
                                            = $85.
Remove detached rubber material..........  5 work hours x $85 per hour            0          425         419,475
                                            = $425.
Replace fuel tank connection hose........  10 work hours x $85 per              383        1,233       1,216,971
                                            hour = $850.
----------------------------------------------------------------------------------------------------------------

    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some of the costs of this 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 has determined that 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 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:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

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


Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  39.13 by:
0
a. Removing Airworthiness Directive 2020-14-06, Amendment 39-21160 (85 
FR 42687, July 15, 2020); and
0
b. Adding the following new airworthiness directive:

2026-06-03 Diamond Aircraft Industries Inc: Amendment 39-23291; 
Docket No. FAA-2025-5397; Project Identifier MCAI-2025-00972-A.

(a) Effective Date

    This airworthiness directive (AD) is effective April 30, 2026.

(b) Affected ADs

    This AD replaces AD 2020-14-06, Amendment 39-21160 (85 FR 42687, 
July 15, 2020); (AD 2020-14-06).

(c) Applicability

    This AD applies to all Diamond Aircraft Industries Inc. Model DA 
40, DA 40 F, and DA 40 NG airplanes (including Model DA 40 NG 
airplanes that have been converted from the Model DA 40 D), 
certificated in any category.

(d) Subject

    Joint Aircraft System Component (JASC) Code 1410, Hoses and 
tubes.

(e) Unsafe Condition

    This AD was prompted by reports of fuel tank connection hose 
deterioration and reports of affected parts that were installed 
during production on Model DA 40 NG airplanes. The FAA is issuing 
this AD to detect and address such deterioration, which, if not 
corrected, could result in contamination of the fuel system and 
restriction of fuel flow and could lead to fuel starvation and 
reduced control of the airplane.

(f) Compliance

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

(g) Definitions

    For the purpose of this AD, ``affected part'' means a fuel tank 
connection hose that meets the criteria in paragraph (g)(1), (2), or 
(3) of this AD.
    (1) Part number (P/N) D4D-2817-10-70 installed during production 
on Model DA 40 NG airplanes with a serial number listed in

[[Page 14645]]

Section I.2. of Diamond Aircraft Industries Mandatory Service 
Bulletin MSB 40NG-064 Rev. 3, dated January 23, 2025; or
    (2) P/N D4D-2817-10-70 or BENOLPRESS (no part number) purchased 
between July 13, 2017, and February 26, 2019, as listed in Section 
I.11 of Diamond Aircraft Industries Mandatory Service Bulletin No. 
MSB 40-087, Revision 3, dated November 5, 2019; Diamond Aircraft 
Industries Mandatory Service Bulletin No. MSB 40NG-064 Rev. 3, dated 
January 23, 2025; or Diamond Aircraft Industries Mandatory Service 
Bulletin No. MSB F4-037, Revision 3, dated November 5, 2019; or
    (3) P/N D4D-2817-10-70 installed as a replacement part on or 
after July 13, 2017, if it is unknown whether the part meets the 
criteria in paragraph (g)(1) or (2) of this AD.

(h) Required Actions

    Within 100 hours time-in-service or within 2 months, whichever 
occurs first after the effective date of this AD, replace each 
affected part as defined in paragraph (g) of this AD, inspect the 
main fuel tank chambers, and remove any detached rubber material in 
accordance with Sections III.1 and III.2 of the Instructions in 
Diamond Aircraft Industries Work Instruction WI-MSB 40-087, Revision 
0, dated July 1, 2019; Diamond Aircraft Industries Work Instruction 
WI-MSB F4-037, Revision 0, dated July 1, 2019; or Diamond Aircraft 
Industries Work Instruction WI-MSB 40NG-064, Revision 0, dated July 
1, 2019; as applicable to your model airplane.

(i) No Reporting Requirement

    Although the service material specifies to submit information to 
the manufacturer, this AD does not require that action.

(j) Installation Prohibition

    As of the effective date of this AD, do not install an affected 
part, as defined in paragraph (g) of this AD, on any airplane.

(k) Credit for Previous Actions

    This paragraph provides credit for the actions required by 
paragraph (h) of this AD if those actions were performed before the 
effective date of this AD, and the affected part for the Model DA 40 
NG airplane was identified using Diamond Aircraft Industries 
Mandatory Service Bulletin No. MSB 40NG-064, Revision 2, dated 
August 29, 2019.

(l) 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 (m)(1) of 
this AD and email it to: [email protected].
    (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.

(m) Additional Information

    (1) For more information about this AD, contact Joseph 
Catanzaro, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 
410, Westbury, NY 11590; phone: (516) 228-7366; email: 
[email protected].
    (2) Material identified in this AD that is not incorporated by 
reference is available at the address specified in paragraph (n)(5) 
of this AD.

(n) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) 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.
    (3) The following material was approved for IBR on April 30, 
2026.
    (i) Diamond Aircraft Industries Mandatory Service Bulletin MSB 
40NG-064 Rev. 3, dated January 23, 2025.
    (ii) [Reserved]
    (4) The following material was approved for IBR on August 4, 
2020 (85 FR 42687, July 15, 2020).
    (i) Diamond Aircraft Industries Mandatory Service Bulletin No. 
MSB 40-087, Revision 3, dated November 5, 2019.
    (ii) Diamond Aircraft Industries Mandatory Service Bulletin No. 
MSB F4-037, Revision 3, dated November 5, 2019.
    (iii) Diamond Aircraft Industries Work Instruction WI-MSB 40-
087, Revision 0, dated July 1, 2019.
    (iv) Diamond Aircraft Industries Work Instruction WI-MSB 40NG-
064, Revision 0, dated July 1, 2019.
    (v) Diamond Aircraft Industries Work Instruction WI-MSB F4-037, 
Revision 0, dated July 1, 2019.
    (5) For Diamond Aircraft Industries material identified in this 
AD, contact Diamond Aircraft Industries Inc., 1560 Crumlin Sideroad, 
London, Ontario, Canada, N5V 1S2; phone: (519) 457-4041, fax: (519) 
457-4045; email: [email protected].
    (6) 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.
    (7) 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 March 18, 2026.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2026-05883 Filed 3-25-26; 8:45 am]
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