DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-2143; Project Identifier MCAI-2023-00088-A;
Amendment 39-22718; AD 2024-06-13]
RIN 2120-AA64

Airworthiness Directives; Diamond Aircraft Industries GmbH
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2022-21-15
for certain Diamond Aircraft Industries GmbH (DAI) Model DA 42, DA 42
NG, and DA 42 M-NG airplanes. AD 2022-21-15 required replacing the
rudder T-yoke axle with an improved rudder T-yoke axle. Since the FAA
issued AD 2022-21-15, the European Union Aviation Safety Agency (EASA)
superseded its mandatory continuing airworthiness information (MCAI) to
correct an unsafe condition on these products. This AD requires, for
certain airplanes, inspecting the rudder steering bracket edge distance
and depending on the inspection results, inspecting the T-yoke bolt
hole for wear and play, and corrective action if necessary. For certain
airplanes this AD requires replacing the rudder T-yoke bolt (axle) with
a serviceable part, installing a new self-locking nut, and applying
torque seal marks on the rudder T-yoke bolt head and self-locking nut.
For all airplanes this AD requires repetitively inspecting the torque
seal marks on the rudder T-yoke bolt head for proper alignment and the
self-locking nut for proper installation and corrective action if
necessary. This AD also prohibits the installation of affected parts.
The FAA is issuing this AD to address the unsafe condition on these
products.

DATES: This AD is effective May 28, 2024.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of May 28, 2024.

ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2023-2143; 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 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:
For service information contact Diamond Aircraft
Industries GmbH, N.A. Otto-Strase 5, A-2700 Wiener Neustadt,
Austria; phone: +43 2622 26700; email: airworthiness-austria@diamondaircraft.com;
website: diamondaircraft.com.
You may view this service information 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-2023-2143.

FOR FURTHER INFORMATION CONTACT: Penelope Trease, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
phone: (303) 342-1094; email: penelope.trease@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2022-21-15, Amendment 39-22214 (87 FR
67541, November 9, 2022) (AD 2022-21-15). AD 2022-21-15 applied to
certain DAI Model DA 42, DA 42 NG, and DA 42 M-NG airplanes. AD 2022-
21-15 was prompted by MCAI originated by EASA, which is the Technical
Agent for the Member States of the European Union. EASA issued EASA AD
2019-0302, dated December 13, 2019 (EASA AD 2019-0302) to correct an
unsafe condition on DAI Model DA 42, DA 42 NG, and DA 42 M-NG
airplanes. EASA AD 2019-0302 described the unsafe condition as reports
of a loose rudder T-yoke axle nut on DAI Model DA 42 airplanes and the
need for new inspections for correct installation of the self-locking
nut to the rudder T-yoke standard bolt LN 9037 (dimensions M6x90), and
depending on findings, accomplishment of applicable corrective
action(s) and replacement of the self-locking nut. EASA AD 2019-0302
also provided an optional terminating action for the repetitive
inspections. This condition, if not detected and corrected, could lead
to vertical movement of the bolt, possibly resulting in reduced rudder
control of the airplane.
AD 2022-21-15 required replacing the rudder T-yoke axle with an
improved rudder T-yoke bolt. The FAA issued AD 2022-21-15 to prevent
movement of the T-yoke bolt.
The NPRM published in the Federal Register on November 8, 2023 (88
FR 77060). The NPRM was prompted by EASA AD 2023-0013, dated January
18, 2023 (EASA AD 2023-0013) (also referred to as the MCAI) for all
Model DA 42, DA 42 M, DA 42 NG, and DA 42 M-NG airplanes. EASA AD 2023-
0013 superseded EASA AD 2019-0302.
The MCAI states that since EASA AD 2019-0302 was issued, DAI
published revised service information to provide additional inspection
and modification instructions. The MCAI requires a one-time inspection
of the rudder steering bracket for insufficient edge distance or wear,
replacement of rudder T-yoke standard bolt LN 9037 (dimensions M6x90)
with rudder T-yoke bolt part number (P/N) D60-5320-00-32, repetitive
inspections of rudder T-yoke bolt P/N D60-5320-00-32 for correct
installation, corrective actions if necessary, and prohibits
installation of rudder T-yoke standard bolt LN 9037 (dimensions M6x90).
The affected and serviceable parts, identified as ``bolt'' in EASA AD
2023-0013, were referred to as ``axle'' in EASA AD 2019-0302.
This condition, if not detected and corrected, could lead to
blockage or loss of rudder control. You may examine the MCAI in the AD
docket at regulations.gov under Docket No. FAA-2023-2143.
In the NPRM the FAA proposed to require, for certain airplanes,
inspecting the rudder steering bracket edge distance and depending on
the inspection results, inspecting the T-yoke bolt hole for wear and play,
and corrective action if necessary. For certain airplanes, the NPRM
proposed to require replacing the rudder T-yoke bolt (axle) with a
serviceable part and applying torque seal marks on the rudder T-yoke
bolt head, and self-locking nut. For all airplanes, the NPRM proposed
to require repetitively inspecting the torque seal marks on the rudder
T-yoke bolt head for proper alignment and the self-locking nut for
proper installation and corrective action if necessary. The NPRM also
proposed to prohibit the installation of affected parts.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from three commenters. The commenters
were two individuals and DAI. The individuals supported the NPRM
without any changes. The following presents the comments received on
the NPRM and the FAA's response to each comment.

Request To Extend the Compliance Time

DAI requested that the compliance time in the proposed AD be
changed from ``Within 200 hours time-in-service (TIS) or 9 months after
the effective date of this AD, whichever occurs first'' to ``Within 200
flight hours or 12 months after the effective date of this AD,
whichever occurs first.'' DAI explained that the pilot and passenger
seats need to be removed prior to the inspection of the rudder steering
bracket and the installation of the improved T-yoke bolt and that the
removal of these seats is already part of an airplane's annual
inspection. DAI noted that extending the compliance time from 9 months
to 12 months would allow operators to align the requirements specified
in the proposed AD with an airplane's scheduled annual inspection. DAI
mentioned that this would avoid unnecessary financial burden for
operators. DAI also noted that the formation of wear in the hole in the
rudder steering bracket is related to flight time and not a specific
period of time. In addition, DAI emphasized that an unnecessary
maintenance action that can be avoided also avoids possible maintenance
errors.
The FAA agrees with the commenter's request to extend the
compliance time from 9 months to 12 months and revised paragraph (h)(1)
of this AD to specify ``Within 200 hours time-in-service (TIS) or 12
months after the effective date of this AD, whichever occurs first . .
. .'' Extending the compliance time by 3 months will not adversely
affect safety and will allow the inspection of the rudder steering
bracket and the installation of the improved T-yoke bolt to be
performed during the annual inspection. The FAA does not agree to
change ``Within 200 hours time-in-service (TIS) . . . .'' to ``Within
200 flight hours . . . .'' Although the MCAI compliance time specifies
``flight hours'' this AD requires using ``hours TIS'' because ``TIS''
is defined in FAA regulations and is used with respect to maintenance
records and ``flight hours'' is not defined in FAA regulations.

Request To Require Entire Work Instruction Instead of Specific Steps

DAI requested that instead of referring to specific steps in the
work instructions identified in paragraphs (h)(1) and (2) and paragraph
(i) of the proposed AD that the entire work instruction be referred to.
DAI stated that it is important to reference the entire document and
include all of the steps instead of specific steps because there are
additional steps that were not identified in paragraphs (h)(1) and (2)
and paragraph (i) of the proposed AD that operators need to do in order
to complete the required actions specified in the proposed AD. DAI
provided the example that operators must do step 9, release rudder
cable turnbuckles, of Diamond Aircraft Work Instruction WI-MSB 42-143
and WI-MSB 42NG-086, Revision 3, dated November 15, 2022 (issued as one
document) attached to Diamond Aircraft Mandatory Service Bulletin DAI
MSB 42-143/1 and DAI MSB 42NG-086/1, dated January 25, 2022 (issued as
one document) because it is important that the T-yoke bolt and self-
locking nut are tightened with released rudder cable tension.
The FAA agrees to require additional steps from the applicable work
instructions in paragraphs (h)(2) and (i) of this AD but does not agree
to require compliance with the entire work instruction document. The
requirements of this AD correspond with the requirements in EASA AD
2023-0013. EASA AD 2023-0013 only requires the following specific steps
from the work instructions: inspecting the edge distance and repair if
required, inspecting the hole and repair if required, replacing an
affected part with a serviceable part, and marking the head of the T-
yoke bolt and the self-locking nut.
The FAA acknowledges that doing additional steps in the work
instructions is necessary to complete the actions required by this AD,
for example, removing the pilot and passenger seats prior to the
inspection of the rudder steering bracket and the installation of the
improved T-yoke bolt; however, to provide operators flexibility
regarding how the required steps are accomplished, the FAA does not
require that operators follow all of the steps in the work
instructions. For example, 14 CFR part 135 operators could have their
own maintenance program which includes instructions regarding pilot and
passenger seat removal. Requiring seat removal in accordance with the
work instructions would create an unnecessary burden on operators
because they would have to submit an alternative method of compliance
(AMOC) request to the FAA if they did not follow the process specified
in the work instructions to remove the seats.
Paragraph (h)(2) of this AD was revised to add steps 9 and 10 of
Diamond Aircraft Work Instruction WI-MSB 42-143 and WI-MSB 42NG-086,
Revision 3, dated November 15, 2022 (issued as one document) attached
to Diamond Aircraft Mandatory Service Bulletin DAI MSB 42-143/1 and DAI
MSB 42NG-086/1, dated January 25, 2022 (issued as one document), with
the exception that instead of discarding a self-locking nut an operator
is required to remove that part from service. Steps 9 and 10 of that
work instruction specify releasing the rudder cable turnbuckles and
removing and discarding the self-locking nut of the T-yoke bolt.
Paragraph (i) of this AD was revised to add steps 6 through 9 of
the Instructions, Section III, in Diamond Aircraft Work Instruction WI-
RSB 42-139 and WI-RSB 42NG-081, Revision 2, dated November 15, 2022
(issued as one document) attached to Diamond Aircraft Recommended
Service Bulletin DAI RSB 42-139 and DAI RSB 42NG-081, dated October 21,
2019 (issued as one document), with the exception that instead of
discarding a self-locking nut an operator is required to remove that
part from service. Steps 6 through 9 of that work instruction are
included in the ``Replacement of rudder T-yoke bolt'' instructions and
specify procedures for accessing the rudder T-yoke bolt, which include
disconnecting the nose landing gear (NLG) steering linkage at the
steering cardan in the wheel well, releasing the rudder cable
turnbuckles, removing the self-locking nut of the T-yoke bolt,
discarding the nut, and removing the T-yoke bolt from the rudder
steering bracket.

Request To Require Application of Torque Seal Marks for Group 1 Minus
Group 2 Airplanes

DAI requested that the requirement to apply torque seal marks be
added in paragraph (h) of the proposed AD because that action should
also be done on Group 1 minus Group 2 airplanes. DAI noted that the
requirement to apply torque seal marks was only included in paragraph
(i) of the proposed AD and was only applicable to Group 2 airplanes.
The FAA agrees with the commenter's request but instead of revising
paragraph (h) of this AD, the FAA revised paragraph (i) of this AD to
change the header from ``Replacement'' to ``Replacement and Application
of Torque Seal Marks,'' added paragraph (i)(1) that is applicable to
Group 1 airplanes that are not also Group 2 airplanes, and moved the
content of paragraph (i) of the proposed AD to paragraph (i)(2) of this
AD.

Request To Have Operator Contact Only DAI for Post-Inspection
Instructions

DAI requested that paragraphs (h)(3) and (4) of the proposed AD be
revised to require operators to contact only DAI for post-inspection
instructions instead of contacting ``. . . the Manager, International
Validation Branch, FAA; the European Union Aviation Safety Agency
(EASA); or Diamond's EASA Design Organization Approval (DOA) . . . .''
DAI noted that depending on the extent of the inspection findings, in
the case of a too large edge distance or a worn or enlarged hole on the
rudder steering bracket, the rudder steering bracket could be repaired
instead of being replaced. The commenter stated that the intention is
to avoid the replacement of the rudder steering bracket if possible,
but this has to be determined for each airplane by DAI experts.
The FAA does not agree with the commenter's request. The FAA
acknowledges that not all discrepancies will result in a rudder
steering bracket having to be replaced and that some rudder steering
brackets can be repaired. The FAA cannot delegate repair approval
authority to a single outside entity; however, the current language in
paragraphs (h)(3) and (4) of this AD provides operators the option to
contact DAI's EASA DOA with the inspection findings for a determination
regarding if the affected rudder steering bracket can be repaired or
must be replaced. The FAA has not changed this AD regarding this issue.

Request To Clarify "Proposed AD Requirements in This NPRM" Section

DAI requested clarification of the proposed requirement regarding
repetitive inspections of the torque seal marks in the ``Proposed AD
Requirements in this NPRM'' section of the NPRM. DAI stated that
existing wording could be misinterpreted to mean the inspections would
only apply to the torque seal marks on the T-yoke bolt head and
clarification was needed to specify that the repetitive inspections are
visual inspections of the torque seal marks for proper alignment on the
T-yoke bolt head and the self-locking nut.
The FAA acknowledges the commenter's request and agrees that the
proposed wording clarifies the requirement in this AD regarding the
repetitive inspections of the torque seal marks; however, the
``Proposed AD Requirements in this NPRM'' section is not carried over
to the final rule. The FAA has not changed this AD regarding this
issue.

Conclusion

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 referenced above. The FAA reviewed the relevant data,
considered the 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
any changes described previously, this AD is adopted as proposed in the
NPRM. None of the changes will increase the economic burden on any
operator.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Diamond Aircraft Mandatory Service Bulletin DAI
MSB 42-143/1 and DAI MSB 42NG-086/1, dated January 25, 2022 (issued as
one document), published with DAI Work Instruction WI-MSB 42-143 and
WI-MSB 42NG-086, Revision 3, dated November 15, 2022 (issued as one
document) attached. The service bulletin specifies compliance with the
work instruction, which contains procedures for inspecting the hole
position and condition in the rudder steering bracket.
The FAA also reviewed Diamond Aircraft Mandatory Service Bulletin
DAI MSB 42-146 and DAI MSB 42NG-087, dated November 15, 2022 (issued as
one document). The service bulletin specifies the serial numbers for
affected airplanes defined as Group 2 airplanes in paragraph (g)(2) of
this AD.
In addition, the FAA reviewed Diamond Aircraft Recommended Service
Bulletin DAI RSB 42-139 and DAI RSB 42NG-081, dated October 21, 2019
(issued as one document), published with DAI Work Instruction WI-RSB
42-139 and WI-RSB 42NG-081, Revision 2, dated November 15, 2022 (issued
as one document) attached. The service bulletin specifies compliance
with the work instruction, which contains procedures for replacement of
the rudder T-yoke axle with an improved (additional retaining pin)
rudder T-yoke axle.
This service information is reasonably available because the
interested parties have access to it through their normal course of
business or by the means identified in ADDRESSES.

Differences Between This AD and the MCAI

The MCAI applies to DAI Model DA 42 M airplanes and this AD does
not because those airplanes do not have an FAA type certificate.
Paragraph (1) of the MCAI specifies a compliance time of within 200
flight hours or 9 months after the effective date of the MCAI,
whichever occurs first, for measuring the distance between the edge of
the rudder steering bracket hole and rear edge of the rudder steering
bracket but this AD requires doing that action within 200 hours TIS or
12 months after the effective date of this AD, whichever occurs first.
Extending the compliance time by three months will not adversely affect
safety and will allow this action to be done during regularly scheduled
maintenance. Although the MCAI compliance time specifies ``flight
hours'' this AD requires using ``hours TIS.''
Paragraph (3) of the MCAI specifies to contact the manufacturer for
repair instructions and paragraph (7) of the MCAI specifies to contact
the manufacturer for corrective actions if any discrepancy is found,
but for both of those corrective actions, this AD requires contacting
either the Manager, International Validation Branch, FAA; EASA; or
Diamond's EASA DOA instead. If approved by the DOA, the approval must
include the DOA-authorized signature.

Costs of Compliance

The FAA estimates that this AD affects 205 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:


Estimated Costs

The FAA estimates the following costs to do any necessary on-
condition action that would be required based on the results of any
required actions. The FAA has no way of determining the number of
aircraft that might need this on-condition action:

On-Condition Costs

Since the replacement or repair instructions could vary
significantly from airplane to airplane if discrepancies are found
during the inspections, the FAA has no data to determine the number of
airplanes that would need follow-on actions or what the cost per
airplane would be.

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

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 2022-21-15, Amendment 39-22214 (87
FR 67541, November 9, 2022); and

b. Adding the following new airworthiness directive: