[4910-13-P]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-1696; Project Identifier MCAI-2023-01234-A]
RIN 2120-AA64
Airworthiness Directives; Diamond Aircraft Industries Inc. (Type Certificate
Previously Held by Diamond Aircraft Industries GmbH) Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 2009-1004, which applies to certain Diamond Aircraft Industries GmbH (type certificate now
held by Diamond Aircraft Industries Inc.) Model DA 40 and DA 40 F airplanes. AD
2009-10-04 requires repetitively inspecting the nose landing gear (NLG) leg for cracks
and replacing the NLG leg if cracks are found. Since the FAA issued AD 2009-10-04,
Transport Canada updated mandatory continuing airworthiness information (MCAI) to
correct this unsafe condition on these products. This proposed AD results from changes
made to the part replacement options and the repetitive inspections. This proposed AD
would require doing repetitive detailed inspections of the NLG leg pivot axle for cracking
and if cracking is found replacing that part with a serviceable part. This proposed AD
would also require eventually replacing all NLG legs having certain part numbers with
serviceable parts, if not already done, and prohibit installing affected parts. Replacing
affected parts with serviceable parts would be terminating action for the repetitive
inspections specified in this proposed AD. The FAA is proposing this AD to address the
unsafe condition on these products.

DATES: The FAA must receive comments on this NPRM by [INSERT DATE 45 DAYS
AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].
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. FAA2024-1696; 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 MCAI,
any comments received, and other information. The street address for Docket Operations
is listed above.
Material Incorporated by Reference:
• For Diamond Aircraft Industries material, contact Diamond Aircraft Industries
Inc., 1560 Crumlin Sideroad, London, ON, Canada, N5V 1S2; phone: (519) 457-4041;
email: support-canada@diamondaircraft.com; 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: Gabriel Kim, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (516)
228-7300; email: 9-avs-nyaco-cos@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 ADDRESSES. Include
“Docket No. FAA-2024-1696; Project Identifier MCAI-2023-01234-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 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 Gabriel Kim,
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 2009-10-04, Amendment 39-15899 (74 FR 22435, May 13,
2009) (AD 2009-10-04), for certain Diamond Aircraft Industries GmbH (type certificate
now held by Diamond Aircraft Industries Inc.) Model DA 40 and DA 40 F airplanes.
AD 2009-10-04 was prompted by MCAI originated by the European Union Aviation
Safety Agency (EASA), which is the Technical Agent for the Member States of the
European Union. EASA issued AD 2009-0016, dated January 22, 2009 (EASA AD 20090016), to address fatigue cracking of the NLG leg part number (P/N) D41-3223-10-00 at
the pivot axle.
AD 2009-10-04 superseded and maintains the requirements of AD 2007-17-06,
Amendment 39-15164 (72 FR 46549, August 21, 2007), which required repetitively
inspecting the NLG leg for cracks and replacing the NLG leg if cracks are found. The
FAA issued AD 2009-10-04 to exclude from the applicability any airplanes that have the
improved NLG leg installed.
Actions Since AD 2009-10-04 was Issued
Effective November 15, 2017, the design and oversight responsibilities for the
Model DA 40, DA 40 F, and DA 40 D airplanes were transferred from Diamond Aircraft
Industries GmbH of Austria as the design approval holder, and EASA as the civil
aviation authority, to Diamond Aircraft Industries Inc. (Diamond), of Canada as the new
design approval holder, and Transport Canada as the civil aviation authority. After that
transition, Transport Canada received several in-service reports of P/N D41-3223-10-

00_1 cracking at the pivot axle and in some cases, fracture of the NLG leg. Investigation
revealed that the failures were the result of fatigue cracking.
Since the FAA issued AD 2009-10-04, Transport Canada superseded EASA
AD 2009-0016 and issued Transport Canada AD CF-2023-50, dated July 10, 2023
(Transport Canada AD CF-2023-50), to address failure of the NLG leg at the pivot axle
by requiring initial and repetitive detailed inspections of NLG leg P/N D41-3223-10-00
and P/N D41-3223-10-00_1 to detect cracking, replacing a NLG leg, as required, with a
serviceable part, and prohibiting the installation of NLG leg P/N D41-3223-10-00 or P/N
D41-3223-10-00_1 as a replacement part.
Transport Canada AD CF-2023-20 differed from the Diamond material because
Transport Canada AD CF-2023-20 required a detailed inspection of the pivot axle of the
NLG leg P/N D41-3223-10-00 and P/N D41-3223-10-00_1 using a bright light and 10X
magnifying glass instead of Type II visible dye for the inspection of the pivot axle. After
Transport Canada AD CF-2023-50 was issued, the repetitive inspection interval was
increased from 100 hours air time to 110 hours air time to align with the scheduled 100hour inspection in chapter 5 of the DA 40 series Airplane Maintenance Manual. To
require the change to Transport Canada AD CF-2023-50, Transport Canada issued AD
CF-2023-50R1, dated November 29, 2023 (also referred to as the MCAI). The MCAI
was published to address the time interval change of the repetitive inspection from 100hour intervals to 110-hour intervals.
You may examine the MCAI in the AD docket at regulations.gov under Docket
No. FAA-2024-1696.
Related Material under 1 CFR Part 51
The FAA reviewed Diamond Mandatory Service Bulletin MSB 40-091 Rev. 0,
dated January 18, 2021, published with Diamond Aircraft Industries Work Instruction
WI-MSB 40-091 Rev. 0, dated January 18, 2021 (issued as one document). This material

specifies procedures for doing repetitive dye penetrant inspections of the NLG leg pivot
axle for cracking and replacing the NLG for Model DA 40 airplanes.
The FAA also reviewed Diamond Mandatory Service Bulletin MSB F4-038
Rev. 0, dated January 18, 2021, published with Diamond Aircraft Industries Work
Instruction WI-MSB F4-038 Rev. 0, dated January 18, 2021 (issued as one document).
This material specifies procedures for doing repetitive dye penetrant detailed inspections
of the NLG leg pivot axle for cracking and replacing the NLG for Model DA 40 F
airplanes.
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 ADDRESSES.
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 retain none of the requirements of AD 2009-10-04. This
proposed AD would require doing repetitive detailed inspections of the NLG leg pivot
axle for cracking and if cracking is found replacing that part with a serviceable part. This
proposed AD would require eventually replacing all NLG legs having certain part
numbers with serviceable parts, if not already done, and prohibiting installing affected
parts. Replacing affected parts with serviceable parts would be terminating action for the
repetitive inspections that would be required by this proposed AD.

Differences Between this Proposed AD, the MCAI, and the Material
The MCAI applies to Model DA 40 D airplanes, however, this proposed AD
would not because that model does not have an FAA type certificate.
Although the Diamond material specifies to do dye penetrant inspections, the
MCAI requires, and this proposed AD would require, using a bright light (minimum of
100 foot-candles) and 10X magnifying glass instead of dye penetrant.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 693
airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed AD:
Estimated costs
Action

Labor Cost

Parts Cost

Inspect NLG
leg pivot axle

1 work-hour x
$85 per hour =
$85 per
inspection
cycle
2 work-hours x
$85 per hour =
$170

Replace NLG
leg

$50 per
inspection
cycle

Cost per
airplane
$135 per
inspection
cycle

Cost on U.S.
operators
Up to $93,555
per inspection
cycle

$3,900

$4,070

Up to
$2,820,510

The costs of the proposed inspection and replacement of the NLG leg are based
on all airplanes having an affected NLG installed. The FAA has no way of determining
the number of airplanes that have the affected NLG installed, and those that do not have
one installed would only be affected by the installation prohibition.
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:
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 2009-10-04, Amendment 39-15899 (74 FR
22435, May 13, 2009); and
b. Adding the following new airworthiness directive:
Diamond Aircraft Industries Inc. (Type Certificate Previously Held by Diamond
Aircraft Industries GmbH): Docket No. FAA-2024-1696; Project Identifier MCAI2023-01234-A.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive (AD) by
[INSERT DATE 45 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL
REGISTER].
(b) Affected ADs
This AD replaces AD 2009-10-04, Amendment 39-15899 (74 FR 22435, May 13,
2009) (AD 2009-10-04).
(c) Applicability
This AD applies to Diamond Aircraft Industries Inc. (type certificate previously
held by Diamond Aircraft Industries GmbH) Model DA 40 and DA 40F airplanes, all
serial numbers, certificated in any category.

(d) Subject
Joint Aircraft System Component (JASC) Code 3220, Nose/Tail Landing Gear.
(e) Unsafe Condition
This AD was prompted by failure of a NLG in the area of the pivot axle. The
unsafe condition, if not addressed, could lead to damage to the airplane and injury to
occupants.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Definitions
For the purposes of this AD the definitions in paragraphs (g)(1) through (3) of this
AD apply:
(1) An “affected part” is an NLG leg having either P/N D41-3223-10-00 or P/N
D41-3223-10-00_1.
(2) A “serviceable part” is an NLG leg that is not an affected part. NLG legs
having P/N D41-3223-10-00_2 or P/N D41-3223-10-00_3 are considered serviceable
parts.
(3) The “applicable mandatory service bulletin (MSB) for your airplane” is:
(i) For Model DA 40 airplanes: Diamond Aircraft Industries Mandatory Service
Bulletin MSB 40-091 Rev. 0, dated January 18, 2021, published with Diamond Aircraft
Industries Work Instruction WI-MSB 40-091 Rev. 0, dated January 18, 2021 (issued as
one document).
(ii) For Model DA 40 F airplanes: Diamond Aircraft Industries Mandatory
Service Bulletin MSB F4-038 Rev. 0, dated January 18, 2021, published with Diamond
Aircraft Industries Work Instruction WI-MSB F4-038 Rev. 0, dated January 18, 2021
(issued as one document).

(h) Required Actions
For all airplanes with an affected part installed, do the applicable actions specified
in paragraphs (h)(1) and (2) of this AD.
(1) Within 25 hours time-in-service (TIS) or 30 days after the effective date of
this AD, whichever occurs first, and thereafter at intervals not to exceed 110 hours TIS,
perform the actions required by paragraphs (h)(1)(i) through (v) of this AD:
(i) Prepare the airplane for inspection of the pivot axle of the affected part in
accordance with Section III, Paragraphs 1 through 4, of the Work Instruction of the
applicable MSB for your airplane.
(ii) Clean the pivot axle of the affected part ensuring that any visible dye
inspection residue is removed.
Note 1 to paragraph (h)(1)(ii): Paragraph 5-63, Cleaners and Applicators, of
Chapter 5, Nondestructive Inspection (NDI), Section 5, Penetrant Inspection, of FAA
Advisory Circular 43.13-1B, “Acceptable Methods, Techniques, and Practices – Aircraft
Inspection and Repair,” Change 1, dated September 8, 1998, provides guidance regarding
an approved cleaning method.
(iii) Perform a detailed inspection of the pivot axle of the affected part using a
bright light (minimum of 100 foot-candles) and 10X magnifying glass to detect cracking,
paying special attention to the radius at the top of the pivot axle as shown in Figure 1 of
the Work Instruction of the applicable MSB for your airplane, except where Figure 1
refers to a “dye penetrant inspection” this AD does not require that type of inspection.
(iv) If any cracking is found during any inspection required by paragraph
(h)(1)(iii) of this AD, before further flight, replace the affected part with a serviceable
part, and reinstall the nose wheel fork in accordance with Section III, Paragraphs 8
through 12 of the Work Instruction of the applicable MSB for your airplane.

(v) If no cracking is found during any inspection required by paragraph (h)(1)(iii)
of this AD and the compliance time specified in paragraph (h)(2) of this AD has not been
exceeded, the affected part can remain installed until the compliance time specified in
paragraph (h)(2) of this AD is reached. Reinstall the nose wheel fork in accordance with
Section III, Paragraphs 8 through 12, of the Work Instruction of the applicable MSB for
your airplane.
(2) Within 2,500 hours TIS or 24 months after the effective date of this AD,
whichever occurs first, replace an affected part with a serviceable part. This part
replacement is terminating action for the repetitive inspections required by paragraph
(h)(1) of this AD.
(i) Parts Installation Prohibition
As of the effective date of this AD, do not install an affected part on any airplane.
(j) 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, mail it to the address identified in
paragraph (k)(1) of this AD or email to: 9-AVS-AIR-730-AMOC@faa.gov. If mailing
information, also submit information by email. 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.
(k) Additional Information
(1) For more information about this AD, contact Gabriel Kim, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (516)
228-7300; email: 9-avs-nyaco-cos@faa.gov.

(2) FAA Advisory Circular 43.13-1B, “Acceptable Methods, Techniques, and
Practices – Aircraft Inspection and Repair,” Change 1, dated September 8, 1998, may be
found at drs.faa.gov.
(l) 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.
(i) Diamond Aircraft Industries Mandatory Service Bulletin MSB 40-091 Rev. 0,
dated January 18, 2021, published with Diamond Aircraft Industries Work Instruction
WI-MSB 40-091 Rev. 0, dated January 18, 2021 (issued as one document).
(ii) Diamond Aircraft Industries Mandatory Service Bulletin MSB F4-038 Rev.0,
dated January 18, 2021, published with Diamond Aircraft Industries Work Instruction
WI-MSB F4-038 Rev. 0, dated January 18, 2021 (issued as one document).
(3) For Diamond Aircraft Industries material contact Diamond Aircraft Industries
Inc., 1560 Crumlin Sideroad, London, ON, Canada, N5V 1S2; phone: (519) 457-4041;
email: support-canada@diamondaircraft.com; 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
fr.inspection@nara.gov.

Issued on June 21, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division,
Aircraft Certification Service.
[FR Doc. 2024-14140 Filed: 7/3/2024 8:45 am; Publication Date: 7/5/2024]