[Federal Register Volume 89, Number 137 (Wednesday, July 17, 2024)]
[Rules and Regulations]
[Pages 58061-58064]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-15657]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1885; Project Identifier MCAI-2022-01484-T; 
Amendment 39-22770; AD 2024-12-06]
RIN 2120-AA64


Airworthiness Directives; De Havilland Aircraft of Canada Limited 
(Type Certificate Previously Held by Bombardier, Inc.) Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

[[Page 58062]]


ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and -
402 airplanes. This AD was prompted by reports of moisture in the wing-
to-fuselage joint, between the mating front spar and rear spar frame 
segments. This AD requires a visual inspection of the fuselage front 
and rear spar frames, an ultrasonic test if applicable, other specified 
actions, and repair if necessary. The FAA is issuing this AD to address 
the unsafe condition on these products.

DATES: This AD is effective August 21, 2024.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of August 21, 
2024.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-1885; 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:
     For De Havilland Aircraft material incorporated by 
reference in this AD, contact De Havilland Aircraft of Canada Limited, 
Dash 8 Series Customer Response Centre, 5800 Explorer Drive, 
Mississauga, Ontario, L4W 5K9, Canada; telephone 855-310-1013 or 647-
277-5820; email dehavilland.com">thd@dehavilland.com; website dehavilland.com.
     You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th Street, 
Des Moines, WA. For information on the availability of this material at 
the FAA, call 206-231-3195. It is also available at regulations.gov 
under Docket No. FAA-2023-1885.

FOR FURTHER INFORMATION CONTACT: Deep Gaurav, Aviation Safety Engineer, 
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-
228-7300; email [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain De Havilland 
Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. The NPRM 
published in the Federal Register on September 25, 2023 (88 FR 65635). 
The NPRM was prompted by AD CF-2022-63, dated November 17, 2022, issued 
by Transport Canada, which is the aviation authority for Canada 
(referred to after this as the MCAI). The MCAI states several reports 
of moisture have been found in the wing-to-fuselage joint, between the 
mating front spar and rear spar frame segments. This condition, if not 
corrected, could lead to corrosion and structural degradation of the 
wing-to-fuselage joint and possible wing separation from the airplane.
    In the NPRM, the FAA proposed to require a visual inspection of the 
fuselage front and rear spar frames, an ultrasonic test if applicable, 
other specified actions, and repair if necessary. The FAA is issuing 
this AD to address the unsafe condition on these products.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2023-1885.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from De Havilland. The following 
presents the comment received on the NPRM and the FAA's response.

Request To Update the Service Information

    De Havilland stated that to allow some operators to accomplish the 
AD, an update is necessary to the work instructions in De Havilland 
Aircraft of Canada Limited Service Bulletin 84-53-81, Revision A, dated 
August 23, 2022. The service bulletin is in the process of being 
revised to allow operators an alternative means of accessing the front 
spar joint via the forward fairing rib on certain airplanes.
    To allow operators to use later revisions of the referenced 
document (issued after publication of the AD), either the FAA must 
revise the AD to reference specific later revisions, or operators may 
request approval to use later revisions as an alternative method of 
compliance with this AD under the provisions of paragraph (i)(1) of 
this AD.
    In light of the critical nature of the identified unsafe condition 
(i.e., corrosion and structural degradation of the wing-to-fuselage 
joint), the FAA does not consider it warranted to delay the issuance of 
this final rule until the revised service information is published. The 
FAA has not changed this AD in this regard.

Conclusion

    This product has been approved by the aviation authority of another 
country and is 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 this product. Except for minor editorial 
changes, 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 De Havilland Aircraft of Canada Limited Service 
Bulletin 84-53-81, Revision A, dated August 23, 2022. This material 
specifies procedures for a general visual inspection of the fuselage 
front and rear spar frames (including around the frame bolts) for signs 
of moisture (i.e., stains and streaks). If signs of moisture ingress 
are noted in the affected structure because of this inspection, then an 
ultrasonic test and other specified actions will be required, which 
includes installing a sealant plug, refinishing the frame edge sealing, 
and removing the existing frame recess sealant between the frame and 
struts in the cabin.
    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 41 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

[[Page 58063]]



                                      Estimated Costs for Required Actions
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                                                                                    Cost per       Cost on U.S.
                          Labor cost                              Parts cost        product         operators
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16 work-hours x $85 per hour = $1,360........................          $3,134           $4,494         $184,254
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    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition actions specified in this AD.

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

    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 adding the following new airworthiness 
directive:

2024-12-06 De Havilland Aircraft of Canada Limited (Type Certificate 
Previously Held by Bombardier, Inc.): Amendment 39-22770; Docket No. 
FAA-2023-1885; Project Identifier MCAI-2022-01484-T.

(a) Effective Date

    This airworthiness directive (AD) is effective August 21, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to De Havilland Aircraft of Canada Limited (Type 
Certificate Previously Held by Bombardier, Inc.) Model DHC-8-401 and 
-402 airplanes, certificated in any category, having serial numbers 
4001 and 4003 through 4624 inclusive.

(d) Subject

    Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by reports of moisture in the wing-to-
fuselage joint, between the mating front spar and rear spar frame 
segments. The FAA is issuing this AD to address potential corrosion 
and structural degradation of the wing-to-fuselage joint. The unsafe 
condition, if not addressed, could result in wing separation from 
the airplane.

(f) Compliance

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

(g) Inspection and Corrective Action

    At the applicable compliance times specified in paragraph (g)(1) 
or (2) of this AD, in accordance with Section 3.B., of the 
Accomplishment Instructions of De Havilland Aircraft of Canada 
Service Bulletin 84-53-81, Revision A, dated August 23, 2022, 
complete a general visual inspection of the fuselage spar frames and 
around the frame bolts for signs of moisture ingress (i.e., stains 
and streaks), accomplish other specified actions, and if necessary, 
perform an ultrasonic test. Do all applicable ultrasonic tests 
before further flight. If, during any ultrasonic test, any corrosion 
or structural degradation is found, before further flight, repair 
using a method approved by the Manager, International Validation 
Branch, FAA; or Transport Canada; or De Havilland Aircraft of Canada 
Limited's Transport Canada Design Approval Organization (DAO). If 
approved by the DAO, the approval must include the DAO-authorized 
signature.
    (1) For airplanes that, as of the effective date of this AD, 
have accumulated less than 32,000 total flight cycles: before 
accumulating 40,000 total flight cycles.
    (2) For airplanes that, as of the effective date of this AD, 
have accumulated 32,000 or more total flight cycles: within 8,000 
flight hours or 48 months, whichever occurs first after the 
effective date of this AD.

(h) Credit for Previous Actions

    This paragraph provides credit for actions required by paragraph 
(g) of this AD, if those actions were performed before the effective 
date of this AD using De Havilland Aircraft of Canada Limited 
Service Bulletin 84-53-81, dated May 27, 2022.

(i) Additional AD Provisions

    The following provisions also apply to this AD:
    (1) 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 responsible Flight Standards Office, as 
appropriate. If sending information directly to the manager, 
International Validation Branch, mail it to the address identified 
in paragraph (j) of this AD or email to [email protected]. 
Before using any approved AMOC, notify your appropriate principal 
inspector, or lacking a principal inspector, the manager of the 
responsible Flight Standards Office.
    (2) Contacting the Manufacturer: For any requirement in this AD 
to obtain instructions from a manufacturer, the instructions must be 
accomplished using a method approved by the Manager, International 
Validation Branch, FAA; or Transport Canada; or De Havilland 
Aircraft of Canada Limited's Transport Canada DAO. If approved by 
the DAO, the approval must include the DAO-authorized signature.

(j) Additional Information

    For more information about this AD, contact Deep Gaurav, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; telephone 516-228-7300; email 
[email protected].

[[Page 58064]]

(k) 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 this AD specifies otherwise.
    (i) De Havilland Aircraft of Canada Limited Service Bulletin 84-
53-81, Revision A, dated August 23, 2022.
    (ii) [Reserved]
    (3) For De Havilland Aircraft material incorporated by reference 
in this AD, contact De Havilland Aircraft of Canada Limited, Dash 8 
Series Customer Response Centre, 5800 Explorer Drive, Mississauga, 
Ontario, L4W 5K9, Canada; telephone 855-310-1013 or 647-277-5820; 
email dehavilland.com">thd@dehavilland.com; website dehavilland.com.
    (4) You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th 
Street, Des Moines, WA. For information on the availability of this 
material at the FAA, call 206-231-3195.
    (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/[email protected]">www.archives.gov/federal-register/cfr/[email protected].

    Issued on July 10, 2024.
James D. Foltz,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2024-15657 Filed 7-16-24; 8:45 am]
BILLING CODE 4910-13-P