```

[Federal Register Volume 86, Number 161 (Tuesday, August 24, 2021)]
[Proposed Rules]
[Pages 47258-47260]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-18111]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0694; Project Identifier MCAI-2021-00305-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).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 
airplanes. This proposed AD was prompted by reports of a possible hard 
contact between the #2 top high level sensor (HLS) terminal screw head 
and the #6 outer wing fuel access panel stiffener flange. This proposed 
AD would require removing and replacing or reworking the #6 outer wing 
fuel access panel assembly. 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 October 8, 
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.
     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 [email protected]; 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 at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0694; 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: Thomas Niczky, Aerospace Engineer, 
Avionics and Electrical Systems Section, FAA, New York ACO Branch, 1600 
Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7347; 
fax 516-794-5531; email [email protected].

SUPPLEMENTARY INFORMATION:

[[Page 47259]]

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-2021-0694; Project Identifier 
MCAI-2021-00305-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 NPRM.

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 
Thomas Niczky, Aerospace Engineer, Avionics and Electrical Systems 
Section, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; telephone 516-228-7347; fax 516-794-5531; email [email protected]. Any commentary that the FAA receives which is 
not specifically designated as CBI will be placed in the public docket 
for this rulemaking.

Background

    Transport Canada Civil Aviation (TCCA), which is the aviation 
authority for Canada, has issued TCCA AD CF-2021-08, dated March 9, 
2021 (TCCA AD CF-2021-08) (also referred to after this as the Mandatory 
Continuing Airworthiness Information, or the MCAI), to correct an 
unsafe condition for De Havilland Aircraft of Canada Limited Model DHC-
8-401 and -402 airplanes, serial numbers 4001 and 4003 through 4628 
inclusive. You may examine the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-
0694.
    This proposed AD was prompted by the discovery that as a result of 
build tolerances, a hard contact could occur between the #2 top HLS 
terminal screw head and the #6 outer wing fuel access panel stiffener 
flange. The FAA is proposing this AD to address the possibility of 
electrical arcing during a lightning strike, which could be a source of 
ignition inside the fuel tank. 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 
84-57-35, Revision A, dated February 11, 2021. This service information 
describes procedures for replacing or reworking the #6 outer wing fuel 
access panel assembly. The rework involves an eddy current or 
fluorescent liquid penetrant inspection of the rework area for crack 
indications. 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 AD Requirements in This NPRM

    This proposed AD would require accomplishing the actions specified 
in the service information already described.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 54 airplanes of U.S. registry. For either replacement or repair 
of the #6 outer wing fuel access panel, depending on the option 
selected by the operator to comply with this proposed AD, the FAA 
estimates the following costs:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
             Action                      Labor cost                 Parts cost              Cost per product
----------------------------------------------------------------------------------------------------------------
Replacement.....................  Up to 10 work-hours x     Up to $16,430............  Up to $17,280.
                                   $85 per hour = Up to
                                   $850.
Repair..........................  13 work-hours x $85 per   $49......................  $1,154.
                                   hour = $1,105.
----------------------------------------------------------------------------------------------------------------

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

[[Page 47260]]

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) 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 
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 adding the following new airworthiness 
directive:

De Havilland Aircraft of Canada Limited (Type Certificate Previously 
Held by Bombardier, Inc.): Docket No. FAA-2021-0694; Project 
Identifier MCAI-2021-00305-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by October 8, 2021.

(b) Affected ADs

    None.

(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 4628 inclusive.

(d) Subject

    Air Transport Association (ATA) of America Code 57, Wings.

(e) Unsafe Condition

    This AD was prompted by reports of a possible hard contact 
between the #2 top high level sensor (HLS) terminal screw head and 
the #6 outer wing fuel access panel stiffener flange. The FAA is 
issuing this AD to address the possibility of electrical arcing 
during a lightning strike, which could be a source of ignition 
inside the fuel tank.

(f) Compliance

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

(g) Required Actions

    Within 8,000 flight hours after the effective date of this AD: 
Do the actions specified in paragraph (g)(1) or (2) of this AD.
    (1) Replace the #6 outer wing fuel access panel assembly in 
accordance with Section 3.B., Part A, of the Accomplishment 
Instructions of De Havilland Aircraft of Canada Limited Service 
Bulletin 84-57-35, Revision A, dated February 11, 2021.
    (2) Rework the #6 outer wing fuel access panel assembly, 
including an eddy current or fluorescent liquid penetrant inspection 
for crack indications of the rework area, in accordance with Section 
3.B., Part B, of the Accomplishment Instructions of De Havilland 
Aircraft of Canada Limited Service Bulletin 84-57-35, Revision A, 
dated February 11, 2021. If any crack indication is found, before 
further flight, repair using a method approved in accordance with 
the procedures specified in paragraph (j)(2) of this AD.

(h) Parts Installation Prohibition

    As of the effective date of this AD, no person may install a #6 
outer wing fuel access panel assembly, part numbers (P/Ns) 85714233-
003/-004 and 85714233-005/-006, on any airplane.

(i) 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 84-57-35, dated October 1, 2020.

(j) 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 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.

(k) Related Information

    (1) Refer to Mandatory Continuing Airworthiness Information 
(MCAI) TCCA AD CF-2021-08, dated March 9, 2021, 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-2021-0694.
    (2) For more information about this AD, contact Thomas Niczky, 
Aerospace Engineer, Avionics and Electrical Systems Section, FAA, 
New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 
11590; telephone 516-228-7347; fax 516-794-5531; email [email protected].
    (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 [email protected]; 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 August 18, 2021.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2021-18111 Filed 8-23-21; 8:45 am]
BILLING CODE 4910-13-P
```