DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-0975; Product Identifier 2020-NM-061-AD]
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.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive
(AD)
for certain De Havilland Aircraft of Canada Limited Model DHC-8-400,
-401, and -402 airplanes. This proposed AD was
prompted by a report of main landing gear (MLG) retractions after
striking an obstacle or severe wheel imbalance after a tire failure.
This proposed AD would require inspections for correct height of the
lock link over-center stop pin and for correct gaps of the left-hand
and right-hand MLG downlock proximity sensors, replacement of the shim
if necessary, and corrective actions, and installation of a new
improved proximity sensor electronic unit (PSEU) with software changes.
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 December
17, 2020.
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 https://www.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.
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 thd@dehavilland.com; 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-2020-0975;
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. Comments will be
available in the AD docket shortly after receipt.
FOR FURTHER INFORMATION CONTACT: Darren Gassetto, Aerospace Engineer,
Mechanical Systems and Administrative Services Section, FAA, New York
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
telephone 516-228-7323; fax 516-794-5531; 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 the ADDRESSES section. Include "Docket No. FAA-2020-0975;
Product Identifier 2020-NM-061-AD" 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
Darren Gassetto, Aerospace Engineer, Mechanical Systems and
Administrative Services Section, FAA, New York ACO Branch, 1600 Stewart
Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7323; 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.
Discussion
Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian AD CF-2016-31R1, dated March
24, 2017 (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, -401, and -402 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. FAA-2020-0975.
This proposed AD was prompted by a report of MLG retractions after
striking an obstacle or severe wheel imbalance after a tire failure.
The FAA is proposing this AD to address loss of MLG downlock signal
caused by the vibrations from those events, which leads to de-
energizing the MLG solenoid sequence valve (SSV) and subsequent removal
of hydraulic pressure from the MLG downlock actuator. Loss of the
hydraulic pressure in the downlock actuator, combined with the
vibrations, can cause the stabilizer brace to unlock and the MLG to
subsequently retract. See the MCAI for additional background
information.
Related Service Information Under 1 CFR Part 51
De Havilland Aircraft of Canada Limited has issued Bombardier
Service Bulletin 84-32-140, Revision B, dated January 30, 2018. This
service information describes set-up procedures for proper
configuration of the MLG prior to performing subsequent procedures for
inspections for correct height of the lock link over-center stop pin
and for correct gaps of the left-hand and right-hand MLG downlock
proximity sensors, and replacement of the shim.
De Havilland Aircraft of Canada Limited has also issued Bombardier
Service Bulletin 84-32-143, Revision B, dated November 16, 2016, which
describes procedures for installation of a new, improved PSEU, PSEU
30145-0601, with software changes.
De Havilland Aircraft of Canada Limited has also issued Bombardier
Service Bulletin 84-32-149, dated November 16, 2016, which describes
procedures for installation of a new, improved PSEU, PSEU 30145-0602,
with software changes.
These documents are distinct since they apply to different airplane
configurations. 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.
FAA's Determination
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.
Costs of Compliance
The FAA estimates that this proposed AD affects 57 airplanes of
U.S. registry. The FAA estimates the following costs to comply with
this proposed AD:
Estimated Costs for Required Actions
Labor cost |
Parts cost |
Cost per product |
Cost on U.S. operators |
Up to 12 work-hours x $85 per
hour = Up to $1,020 |
Up to $4,750 |
Up to $5,770 |
Up to $328,890 |
The FAA estimates the following
costs to do any necessary on-
condition actions 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 these on-condition actions:
Estimated Costs of On-Condition Actions
Labor cost
|
Parts cost
|
Cost per
product
|
1 work-hour
x $85 per hour = $85
|
$374
|
$459
|
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 this proposed
regulation:
(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 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
directive (AD):
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