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).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2009-10-04, 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 August 19, 2024.

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-2024-1696; 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: diamondaircraft.com">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 2009-0016),
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 100-hour 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 100-
hour 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

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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 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: