DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0183; Project Identifier MCAI-2020-01408-T]
Airworthiness Directives; De Havilland Aircraft of Canada Limited
(Type Certificate Previously Held by Bombardier, Inc.) Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to adopt a new airworthiness directive
for certain De Havilland Aircraft of Canada Limited Model DHC-8-400
series airplanes. This proposed AD was prompted by a report that a
number of nacelle A-frames were not manufactured in accordance with
engineering drawings. This proposed AD would require, depending on
airplane configuration, removing the fasteners on the nacelle A-frame
side brace sub-assemblies, doing an eddy current inspection for
cracking, cold-working the holes, installing oversize fasteners, re-
identifying the reworked side brace fitting and A-frame, and repair if
necessary. The FAA is proposing this AD to address the unsafe condition
on these products.
DATES: The FAA must receive comments on this proposed AD by May
ADDRESSES: You may send comments, using the procedures found in
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
instructions for submitting comments.
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.
For service information identified in this NPRM, contact De
Havilland Aircraft of Canada Limited, Q-Series Technical Help Desk, 123
Garratt Boulevard, Toronto, Ontario M3K 1Y5, Canada; telephone 416-375-
4000; fax 416-375-4539; email firstname.lastname@example.org; internet https://
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.
Examining the AD Docket
You may examine the AD docket on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2021-0183;
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, any comments received, and other information. The street
address for Docket Operations is listed above.
FOR FURTHER INFORMATION CONTACT: Andrea Jimenez, Aerospace Engineer,
Airframe and Propulsion Section, FAA, New York ACO Branch, 1600 Stewart
Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7330; fax 516-
794-5531; email email@example.com.
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-2021-0183; Project Identifier
MCAI-2020-01408-T" 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
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this proposed AD.
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
Andrea Jimenez, Aerospace Engineer, Airframe and Propulsion Section,
FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY
11590; telephone 516-228-7330; fax 516-794-5531; email 9-avs-nyaco-cos@
faa.gov. Any commentary that the FAA receives which is not specifically
designated as CBI will be placed in the public docket for this rulemaking.
Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued TCCA AD CF-2020-39, dated October 14,
2020 (referred to after this as the Mandatory Continuing Airworthiness
Information, or the MCAI), to correct an unsafe condition for certain
De Havilland Aircraft of Canada Limited Model DHC-8-400 series
airplanes. You may examine the MCAI in the AD docket on the internet at
https://www.regulations.gov by searching for and locating Docket No.
This proposed AD was prompted by a report that a number of nacelle
A-frames were not manufactured in accordance with engineering drawings.
The holes in the side brace sub-assemblies were not cold-worked as
required. As a result the side brace fitting might not meet its fatigue
life, and cracking of the A-frame bottom flange may result. The FAA is
proposing this AD to address possible cracking of the A-frame. This
condition, if not addressed, may lead to collapse of the main landing
gear (MLG). See the MCAI for additional background information.
Related Service Information Under 1 CFR Part 51
De Havilland Aircraft of Canada Limited has issued Service Bulletin
84-54-32, dated October 10, 2019. This service information describes
procedures, depending on airplane configuration, for removing the
fasteners on the nacelle A-frame side brace sub-assemblies, doing an
eddy current inspection for cracking, cold-working the holes,
installing oversize fasteners, and re-identifying the reworked side
brace fitting and A-frame.
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.
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 the State of Design Authority,
the FAA has been notified of the unsafe condition described in the MCAI
and service information referenced above. The FAA is proposing this AD
because the FAA evaluated all the relevant information and determined
the unsafe condition described previously is likely to exist or develop
on other products of the same type design.
Proposed Requirements of This NPRM
This proposed AD would require accomplishing the actions specified
in the service information described previously. This proposed AD would
also require repairing any crack found during an eddy current
Costs of Compliance
The FAA estimates that this proposed AD affects 41 airplanes of
U.S. registry. The FAA estimates the following costs to comply with
this proposed AD:
Estimated Costs for Required Actions
|15 work-hours x $85 per hour
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.
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 this proposed
(1) Is not a "significant regulatory action" under Executive
(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
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 adding the following new airworthiness