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2022-25-06 DE HAVILLAND AIRCRAFT OF CANADA LIMITED (TYPE CERTIFICATE PREVIOUSLY HELD BY BOMBARDIER, INC.): Amendment 39-22262; Docket No. FAA-2022-0993; Project Identifier MCAI-2022-00295-T
(a) EFFECTIVE DATE

    This airworthiness directive (AD) is effective January 23, 2023.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This AD applies to De Havilland Aircraft of Canada Limited  (Type Cer-
    tificate previously held by Bombardier Inc) Model DHC-8-402 airplanes,
    certificated in any category,  serial numbers 4095 through 4633 inclu-
    sive.

(d) SUBJECT

    Air Transport Association (ATA) of America Code 21,  Air  Conditioning
    System.

(e) UNSAFE CONDITION

    This AD was  prompted by an  investigation that found  that the actual
    operating temperatures within the integrated flight cabinet (IFC) were
    significantly  higher  than  anticipated  during  the   certification.
    Consequently, the reliability of the  IFC module does not meet  safety
    objectives. The FAA is issuing  this AD to address the  high operating
    temperatures  within  the  IFC,  which  could  lead  to   uncontrolled
    autopilot pitch trim  servo runaway and  failure of the  stall warning
    and  stick  pusher,  resulting  in  reduced  controllability  of   the
    airplane.

(f) COMPLIANCE

    Comply with this AD within the compliance times specified,  unless al-
    ready done.

(g) REQUIRED ACTIONS

    Within 8,000 flight hours or  48 months, whichever occurs first,  from
    the effective date of  this AD, do a  modification to improve the  IFC
    cooling capacity, in accordance  with paragraph 3.B., "Procedure,"  of
    the Accomplishment  Instructions of  De Havilland  Aircraft of  Canada
    Limited Service Bulletin 84-21-24, Revision B, dated Oct 13, 2021.

(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 84-21-24, Revision A, dated August 20, 2021.

(i) OTHER FAA AD PROVISIONS

    The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs):  The Manager,  New York ACO
    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 of the certification office,  send
    it to ATTN: Program  Manager, Continuing Operational Safety,  FAA, New
    York ACO Branch, 1600 Stewart  Avenue, Suite 410, Westbury, NY  11590;
    telephone 516-228-7300;  fax 516-794-5531.  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,  New York  ACO
    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.

(j) ADDITIONAL INFORMATION

(1) Refer to Transport Canada AD CF-2022-09,  dated March 3, 2022, for re-
    lated information.  This Transport Canada  AD  may be found  in the AD
    docket at regulations.gov under Docket No. FAA-2022-0993.

(2) For more information about this AD, contact Gabriel Kim, Aerospace En-
    gineer,  Mechanical Systems and Administrative Services Section,  FAA,
    New York  ACO Branch,  1600 Stewart Avenue,  Suite 410,  Westbury,  NY
    11590; telephone 516-228-7300; email 9-avs-nyaco-cos@faa.gov.

(3) Service information identified in this AD  that is not incorporated by
    reference is available at the addresses specified in paragraphs (k)(3)
    and (4) of this AD.

(k) MATERIAL INCORPORATED BY REFERENCE

(1) The Director of the Federal Register  approved  the  incorporation  by
    reference of the service information  listed in this paragraph under 5
    U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this service information as applicable  to do the actions
    required by this AD, unless this AD specifies otherwise.

(i) De Havilland Aircraft of Canada Limited Service Bulletin 84-21-24, Re-
    vision B, dated Oct 13, 2021.

(ii) [Reserved]

(3) For service information  identified 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
    North America (toll-free): 855-310-1013,  Direct: 647-277-5820;  email
    thd@dehavilland.com; website dehavilland.com.

(4) You may view this service information at the FAA,  Airworthiness Prod-
    ucts Section,  Operational  Safety  Branch,  2200 South 216th St., Des
    Moines, WA.  For information  on the availability  of this material at
    the FAA, call 206-231-3195.

(5) You may view  this service information  that is incorporated by refer-
    ence at the National Archives and Records Administration  (NARA).  For
    information on the availability of this material  at  NARA,  email fr.
    inspection@nara.gov,  or go to: www.archives.gov/federal-register/cfr/
    ibr-locations.html.

Issued on November 30, 2022. Christina Underwood, Acting Director, Compli-
ance & Airworthiness Division, Aircraft Certification Service.

FOR FURTHER INFORMATION CONTACT: Gabriel Kim, Aerospace Engineer, Mechani-
cal Systems and Administrative Services Section, FAA, New York ACO Branch,
1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300
email 9-avs-nyaco-cos@faa.gov.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0993; Project Identifier MCAI-2022-00295-T;
Amendment 39-22262; AD 2022-25-06]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain De Havilland Aircraft of Canada Limited Model DHC-8-402
airplanes. This AD was prompted by an investigation that found that the
actual operating temperatures within the integrated flight cabinet
(IFC) were significantly higher than anticipated during certification.
This AD requires a modification to improve the IFC cooling capacity.
The FAA is issuing this AD to address the unsafe condition on these
products.

DATES: This AD is effective January 23, 2023.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of January 23,
2023.

ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2022-0993; 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 service information identified in this final rule,
contact De Havilland Aircraft of Canada Limited, Dash 8 Series Customer
Response Centre, 5800 Explorer Drive, Mississauga, Ontario, L4W 5K9,
Canada; telephone North America (toll-free): 855-310-1013, Direct: 647-
277-5820; email thd@dehavilland.com; website dehavilland.com.
You may view this service information at the FAA,
Airworthiness Products Section, Operational Safety Branch, 2200 South
216th St., 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-2022-0993.

FOR FURTHER INFORMATION CONTACT: Gabriel Kim, Aerospace Engineer,
Mechanical Systems and Administrative Services Section, FAA, New York
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
telephone 516-228-7300; email 9-avs-nyaco-cos@faa.gov.

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-8-402 airplanes. The NPRM
published in the Federal Register on August 12, 2022 (87 FR 49776). The
NPRM was prompted by AD CF-2022-09, dated March 3, 2022, issued by
Transport Canada, which is the aviation authority for Canada (referred
to after this as the MCAI) (Transport Canada CF-2022-09). The MCAI
states that as a result of higher-than-expected failure rates in
service, the supplier's investigation found that actual operating
temperatures within the IFC were significantly higher than anticipated
during certification. Consequently, the reliability of the IFC module
does not meet safety objectives. The MCAI further states this failure
mode could lead to uncontrolled autopilot pitch trim servo runaway and/
or failure of the stall warning and stick pusher, resulting in reduced
controllability of the airplane.
In the NPRM, the FAA proposed to require a modification to improve
the IFC cooling capacity. 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-2022-0993.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from the Air Line Pilots Association,
International (ALPA), who supported the NPRM without change.
The FAA received an additional comment from Horizon Air. The
following presents the comment received on the NPRM and the FAA's
response to each comment.

Request To Exclude Job Set-Up and Close-Out

Horizon Air requested that the final rule mandate only paragraph
3.B., ``Procedure,'' of the Accomplishment Instructions of De Havilland
Service Bulletin 84-21-24, Revision B, dated Oct 13, 2021, because that
corrects the unsafe condition. Horizon Air stated that paragraph 3.A.
``Job Set-up,'' and paragraph 3.C., ``Close Out'' of the Accomplishment
Instructions of De Havilland Service Bulletin 84-21-24, Revision B,
dated Oct 13, 2021, do not directly correct the unsafe condition. The
commenter stated that incorporating the ``Job Set-up'' and ``Close
Out'' procedures as a requirement of the AD restricts an operator's
ability to perform other maintenance in conjunction with the
incorporation of the service information.
The FAA agrees with the requested change for the reasons provided
by the commenter. In addition, this change corresponds to Transport
Canada AD CF-2022-09, dated March 3, 2022. The FAA has revised
paragraph (g) of this AD accordingly.

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, 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.

Related Service Information Under 1 CFR Part 51

De Havilland Aircraft of Canada Limited has issued Service Bulletin
84-21-24, Revision B, dated October 13, 2021. This service information
specifies procedures for a modification to improve the IFC cooling
capacity. The tasks include reworking the forward and aft avionics rack
side panels, removing the piccolo tube assemblies, doing a general
visual inspection for contamination of the IFCs and avionics rack,
cleaning any contamination found, installing and routing new cooling
ducts, and installing two new extraction plenums in the avionics rack
cooling system.
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 the ADDRESSES section.

Costs of Compliance

The FAA estimates that this AD affects 56 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:

Estimated Costs for Required Actions

Labor cost
Parts cost
Cost per product
Cost on U.S. operators
11 work-hours x $85 per hour = $935
$6,950
$7,885
$441,560

The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some or all 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

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 adding the following new airworthiness
directive: