[Federal Register Volume 87, Number 213 (Friday, November 4, 2022)]
[Proposed Rules]
[Pages 66619-66623]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-23594]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-1403; Project Identifier MCAI-2022-00122-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 adopt a new airworthiness directive (AD) 
for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and 
-402 airplanes. This proposed AD was prompted by reports of corrosion 
on the horizontal stabilizer lower center skin panel, including a 
finding of corrosion where the skin thickness had been substantially 
reduced, which affected design margins. This proposed AD would require 
inspecting the horizontal stabilizer lower center skin panel for 
corrosion, and reworking, repairing, or replacing the lower center skin 
panel 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 December 
19, 2022.

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 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.
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2022-1403; 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, the mandatory continuing airworthiness 
information (MCAI), any comments received, and other information. The 
street address for Docket Operations is listed above.
    Material Incorporation by Reference:
     For service information identified in this NPRM, contact 
De Havilland Aircraft of Canada Limited, Dash 8 Series Customer 
Response Centre, 5800 Explorer Drive, Mississauga, Ontario, L4W 5K9, 
Canada; telephone 855-310-1013 or 647-277-5820; email 
dehavilland.com">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.

FOR FURTHER INFORMATION CONTACT: Yaser Osman, Aerospace Engineer, 
Airframe and Propulsion Section, FAA, New York ACO Branch, 1600 Stewart 
Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email [email protected].

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-2022-1403; Project Identifier 
MCAI-2022-00122-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 
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

[[Page 66620]]

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 Yaser Osman, Aerospace Engineer, Airframe and Propulsion 
Section, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; telephone 516-228-7300; 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-2022-02, dated January 28, 
2022 (TCCA AD CF-2022-02) (also referred to after this as 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 at regulations.gov under Docket No. FAA-2022-1403.
    This proposed AD was prompted by reports of corrosion on the 
horizontal stabilizer lower center skin panel, including a finding of 
corrosion where the skin thickness had been substantially reduced, 
which affected design margins. The root cause was found to be 
inconsistent chemical processing of the lower center skin panel, with 
missing anodizing layer and primer on some areas of the skin panel 
surface. The FAA is proposing this AD to address possible reduction of 
skin panel thickness due to the effects of corrosion, which could 
compromise the structural integrity of the horizontal stabilizer. 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 
84-55-05, Revision C, dated August 19, 2021. This service information 
describes procedures for inspecting the horizontal stabilizer lower 
center skin panel for corrosion, and, depending on the level of 
corrosion, reworking or repairing the horizontal stabilizer lower 
center skin panel.
    De Havilland Aircraft of Canada Limited has also issued Service 
Bulletin 84-55-11, dated February 16, 2021. This service information 
describes procedures for replacing the horizontal stabilizer lower 
center skin panel.
    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, except as discussed under 
``Differences Between this NPRM and the MCAI or Service Information.''

Differences Between This NPRM and the MCAI or Service Information

    TCCA AD CF-2022-02 specifies credit for repair, rework, or 
replacement of corroded horizontal stabilizer lower center skin panel 
using certain repair drawings. De Havilland Aircraft of Canada Limited 
has informed the FAA that four additional repair drawings are also 
acceptable for credit. Therefore, paragraph (h)(2) of this proposed AD 
would provide credit for those additional repair drawings.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 56 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 per       Cost on U.S.
                          Labor cost                              Parts cost        product         operators
----------------------------------------------------------------------------------------------------------------
108 work-hours x $85 per hour = $9,180.......................              $0           $9,180         $514,080
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary on-
condition replacements 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 this on-condition replacement:

                 Estimated Costs of On-Condition Actions
------------------------------------------------------------------------
                                                             Cost per
              Labor cost                   Parts cost        product
------------------------------------------------------------------------
108 work-hours x $85 per hour = $9.180         $21,449          $30,629
------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition repairs or rework specified in this 
proposed AD.
    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.

[[Page 66621]]

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) 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-2022-1403; Project 
Identifier MCAI-2022-00122-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by December 19, 2022.

(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, having 
serial numbers 4001 and 4003 through 4549 inclusive.

(d) Subject

    Air Transport Association (ATA) of America Code 55, Stabilizers.

(e) Unsafe Condition

    This AD was prompted by reports of corrosion on the horizontal 
stabilizer lower center skin panel, including a finding of corrosion 
where the skin thickness had been substantially reduced, which 
affected design margins. The FAA is issuing this AD to address 
possible substantial reduction of skin panel thickness due to the 
effects of corrosion, which could compromise the structural 
integrity of the horizontal stabilizer.

(f) Compliance

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

(g) Inspection and Corrective Actions

    (1) Within 8,000 flight hours or 48 months, whichever occurs 
first, after the effective date of this AD: Inspect the horizontal 
stabilizer lower center skin panel for corrosion in accordance with 
Section 3.B. Part A of the Accomplishment Instructions of De 
Havilland Aircraft of Canada Service Bulletin 84-55-05 Revision C, 
dated August 19, 2021. If any corrosion is found, before further 
flight, do the applicable actions specified in paragraph (g)(2) or 
(3) of this AD.
    (2) If the corrosion is within the allowable repair limits as 
specified in Figure 5 Detail C of De Havilland Aircraft of Canada 
Service Bulletin 84-55-05 Revision C, dated August 19, 2021, perform 
the corrosion rework in accordance with Section 3.B. Part B of the 
Accomplishment Instructions of De Havilland Aircraft of Canada 
Service Bulletin 84-55-05 Revision C, dated August 19, 2021.
    (3) If the corrosion is beyond the allowable repair limits as 
specified in Figure 5 Detail C of De Havilland Aircraft of Canada 
Service Bulletin 84-55-05 Revision C, dated August 19, 2021, 
accomplish the action specified in paragraph (g)(3)(i) or (ii) of 
this AD.
    (i) Replace the existing horizontal stabilizer lower center skin 
panel in accordance with the Accomplishment Instructions of De 
Havilland Aircraft of Canada Service Bulletin 84-55-11 Initial 
Issue, dated February 16, 2021.
    (ii) Obtain and follow repair instructions 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.

(h) Credit for Previous Actions

    (1) This paragraph provides credit for actions required by 
paragraphs (g)(1) and (2) of this AD, if those actions were 
performed before the effective date of this AD using De Havilland 
Aircraft of Canada Limited Service Bulletin 84-55-05, Initial Issue, 
dated January 12, 2016; De Havilland Aircraft of Canada Limited 
Service Bulletin 84-55-05, Revision A, dated June 3, 2016; De 
Havilland Aircraft of Canada Limited Service Bulletin 84-55-05, 
Revision B, dated February 26, 2021.
    (2) This paragraph provides credit for the actions required by 
paragraph (g)(2) or (3) of this AD, if those actions were performed 
before the effective date of this AD using any of the repair 
drawings (RDs) specified in figure 1 to paragraph (h) of this AD.

Figure 1 to paragraph (h)--Repair Drawings
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[GRAPHIC] [TIFF OMITTED] TP04NO22.061

(i) Additional 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. 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.

(j) Related Information

    (1) Refer to TCCA AD CF-2022-02, dated January 28, 2022, for 
related information. This TCCA AD may be found in the AD docket at 
regulations.gov under Docket No. FAA-2022-1403.
    (2) For more information about this AD, contact Yaser Osman, 
Aerospace Engineer, Airframe and Propulsion Section, FAA, New York 
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
telephone 516-228-7300; email [email protected].
    (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 (IBR) 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-
55-05, Revision C, dated August 19, 2021.
    (ii) De Havilland Aircraft of Canada Limited Service Bulletin 
84-55-11, dated February 16, 2021.
    (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 855-310-1013 or 647-277-5820; email 
dehavilland.com">thd@dehavilland.com; website dehavilland.com.
    (4) 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records

[[Page 66623]]

Administration (NARA). For information on the availability of this 
material at NARA, email [email protected], or go to: 
www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on October 25, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2022-23594 Filed 11-3-22; 8:45 am]
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