[Federal Register Volume 86, Number 35 (Wednesday, February 24, 2021)]
[Proposed Rules]
[Pages 11175-11178]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-03597]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0018; Project Identifier MCAI-2020-01214-T]
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 supersede Airworthiness Directive (AD) 
2015-17-08, which applies to certain Bombardier, Inc. Model DHC-8-400 
series airplanes. AD 2015-17-08 requires installing new cable 
assemblies with a pull-down resistor. Since the FAA issued AD 2015-17-
08, a modification has been developed to address all known single point 
failures that could lead to runaway of the nose wheel steering (NWS) 
system. This proposed AD would require modifications to the NWS system. 
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 April 12, 
2021.

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.

[[Page 11176]]

     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-2021-
0018; 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: Siddeeq Bacchus, Aerospace Engineer, 
Mechanical Systems and Administrative Services Section, FAA, New York 
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
telephone 516-228-7362; 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 ADDRESSES. Include ``Docket No. FAA-2021-0018; Project Identifier 
MCAI-2020-01214-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 
Siddeeq Bacchus, Aerospace Engineer, Mechanical Systems and 
Administrative Services Section, FAA, New York ACO Branch, 1600 Stewart 
Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7362; 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

    The FAA issued AD 2015-17-08, Amendment 39-18241 (80 FR 51459, 
August 25, 2015) (AD 2015-17-08), for certain Bombardier, Inc. Model 
DHC-8-400 series airplanes. AD 2015-17-08 requires installing new cable 
assemblies with a pull-down resistor. AD 2015-17-08 resulted from an 
in-service report of an uncommanded and unannunciated nose wheel 
steering during airplane pushback from the gate. The FAA issued AD 
2015-17-08 to address an uncommanded nose wheel steering during takeoff 
or landing in the event of an open circuit in the steering system, and 
possible consequent runway excursion.

Actions Since AD 2015-17-08 Was Issued

    Since the FAA issued AD 2015-17-08, De Havilland Aircraft of Canada 
Limited has developed a modification to address all known single point 
failures that could lead to runaway of the NWS system. The FAA 
considered AD 2015-17-08 interim action since it did not address all of 
the concerns identified during the design review following the incident 
that prompted AD 2015-17-08. The FAA has determined that the 
modification specified in this proposed AD is necessary to address the 
unsafe condition, including concerns not addressed by AD 2015-17-08.
    Transport Canada Civil Aviation (TCCA), which is the aviation 
authority for Canada, has issued TCCA AD CF-2020-28, dated August 14, 
2020 (also 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-8-401 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-2021-0018.
    This proposed AD was prompted by a report indicating that several 
failure modes of the NWS system may cause the loss of feedback from 
both rotary variable differential transformers to the steering control 
unit. The FAA is proposing this AD to address failure modes of the NWS 
system, which could lead to NWS runaway, loss of directional control of 
the airplane, and possible consequent runway excursion. 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 
84-32-162, Revision B, dated November 13, 2019, including UTC Aerospace 
Systems Service Bulletin 406300-32-142, dated June 24, 2019; and UTC 
Aerospace Systems Service Bulletin 406330-32-143, dated June 24, 2019. 
This service information describes procedures for modifying the NWS 
system (terminating wiring, reworking the left-hand console frame, and 
installing an NWS electronic control unit and NWS hand control). 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

[[Page 11177]]

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 retain none of the requirements of AD 2015-
17-08. 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 54 airplanes of 
U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

                                      Estimated Costs for Required Actions
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                                                                                                  Cost on U.S.
             Action                    Labor cost            Parts cost      Cost per product      operators
----------------------------------------------------------------------------------------------------------------
Modification...................  13 work-hours x $85     Up to $122.......  Up to $1,227.....  Up to $65,258.
                                  per hour = $1,105.
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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 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

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 removing Airworthiness Directive (AD) 
2015-17-08, Amendment 39-18241 (80 FR 51459, August 25, 2015), and 
adding the following new AD:

De Havilland Aircraft of Canada Limited (Type Certificate Previously 
Held by Bombardier, Inc.): Docket No. FAA-2021-0018; Project 
Identifier MCAI-2020-01214-T.

(a) Comments Due Date

    The FAA must receive comments by April 12, 2021.

(b) Affected Airworthiness Directives (ADs)

    This AD replaces AD 2015-17-08, Amendment 39-18241 (80 FR 51459, 
August 25, 2015) (AD 2015-17-08).

(c) Applicability

    This AD applies to De Havilland Aircraft of Canada Limited Model 
DHC-8-401 and -402 airplanes, certificated in any category, serial 
numbers 4001, and 4003 through 4608 inclusive.

(d) Subject

    Air Transport Association (ATA) of America Code 32, Landing 
gear.

(e) Reason

    This AD was prompted by a report indicating that several failure 
modes of the nose wheel steering (NWS) system may cause the loss of 
feedback from both rotary variable differential transformers to the 
steering control unit. The FAA is issuing this AD to address failure 
modes of the NWS system, which could lead to NWS runaway, loss of 
directional control of the airplane, and possible consequent runway 
excursion.

(f) Compliance

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

(g) New Requirement of this AD

    Within 4,000 flight hours or 18 months, whichever occurs first 
after the effective date of this AD: Perform modifications to the 
NWS system, in accordance with paragraph 3.B of the Accomplishment 
Instructions of De Havilland Aircraft of Canada Limited Service 
Bulletin 84-32-162, Revision B, dated November 13, 2019, including 
UTC Aerospace Systems Service Bulletin 406300-32-142, dated June 24, 
2019; and UTC Aerospace Systems Service Bulletin 406330-32-143, 
dated June 24, 2019.

(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 84-32-162, dated August 26, 2019, including UTC 
Aerospace Systems Service Bulletin 406300-32-142, dated June 24, 
2019; and UTC Aerospace Systems Service Bulletin 406330-32-143, 
dated June 24, 2019; or De Havilland Aircraft of Canada Limited 
Service Bulletin 84-32-162, Revision A, dated October 18, 2019, 
including UTC Aerospace Systems Service Bulletin 406300-32-142, 
dated June 24, 2019; and UTC Aerospace Systems Service Bulletin 
406330-32-143, dated June 24, 2019.

(i) Other FAA AD Provisions

    (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.

[[Page 11178]]

    (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 Civil Aviation (TCCA); or De 
Havilland Aircraft of Canada Limited's TCCA Design Approval 
Organization (DAO). If approved by the DAO, the approval must 
include the DAO-authorized signature.

(j) Related Information

    (1) Refer to Mandatory Continuing Airworthiness Information 
(MCAI) Canadian AD CF-2020-28, dated August 14, 2020, for related 
information. This MCAI may be found in the AD docket on the internet 
at https://www.regulations.gov by searching for and locating Docket 
No. FAA-2021-0018.
    (2) For more information about this AD, contact Siddeeq Bacchus, 
Aerospace Engineer, Mechanical Systems and Administrative Services 
Section, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; telephone 516-228-7362; fax 516-794-5531; email 
9-avs-nyaco-cos@faa.gov.
    (3) For service information identified in this AD, 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.

    Issued on January 27, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-03597 Filed 2-23-21; 8:45 am]
BILLING CODE 4910-13-P


