[Federal Register Volume 86, Number 242 (Tuesday, December 21, 2021)]
[Rules and Regulations]
[Pages 72174-72178]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-27709]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-1064; Project Identifier MCAI-2021-01028-T; 
Amendment 39-21856; AD 2021-25-12]
RIN 2120-AA64


Airworthiness Directives; De Havilland Aircraft of Canada Limited 
(Type Certificate Previously Held by Bombardier, Inc.) Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2017-19-
09, which applied to certain De Havilland Aircraft of Canada Limited 
(Type Certificate Previously Held by Bombardier, Inc.) Model DHC-8-400 
series airplanes. AD 2017-19-09 required modifying the nose landing 
gear (NLG) shock strut assembly. This new AD requires repetitive 
lubrications of the trailing arm of the NLG. This new AD also requires 
revising the existing maintenance or inspection program to include new 
and revised airworthiness limitations (life limits for certain bolts). 
This AD was prompted by reports of a certain bolt being found missing 
or having stress corrosion cracking. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective January 5, 2022.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of January 5, 
2022.
    The FAA must receive comments on this AD by February 4, 2022.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:

[[Page 72175]]

     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: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.
    For service information identified in this final rule, 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 referenced 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. It is also 
available on the internet at https://www.regulations.gov by searching 
for and locating Docket No. FAA-2021-1064.

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-
1064; or in person at the Docket Management Facility between 9 a.m. and 
5 p.m., Monday through Friday, except Federal holidays. The AD docket 
contains this AD, any comments received, and other information. The 
street address for the Docket Operations office is listed above. 
Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Antariksh Shetty, Aerospace Engineer, 
Airframe and Propulsion Section, FAA, New York ACO Branch, 1600 Stewart 
Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; fax 516-
794-5531; email [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued AD 2017-19-09, Amendment 39-19039 (82 FR 43829, 
September 20, 2017) (AD 2017-19-09), which applied to certain De 
Havilland Aircraft of Canada Limited (Type Certificate Previously Held 
by Bombardier, Inc.) Model DHC-8-400, -401, and -402 airplanes. AD 
2017-19-09 was prompted by reports of discrepancies of a certain bolt 
at the pivot pin link, resulting in corrosion of the bolt. AD 2017-19-
09 required modifying the NLG shock strut assembly. The FAA issued AD 
2017-19-09 to address failure of the pivot pin retention bolt, which 
could result in a loss of directional control or loss of an NLG tire 
during takeoff or landing.

Actions Since AD 2017-19-09 Was Issued

    Since the FAA issued AD 2017-19-09, the FAA has determined new 
actions are necessary to address the unsafe condition. New bolts that 
have been installed must be repetitively lubricated and replaced before 
reaching their life limit. Failure of the pivot pin retention bolt 
could result in loss of directional control or loss of a NLG tire 
during takeoff or landing, which could lead to runway excursions. The 
actions required by AD 2017-19-09 are not retained in this AD.
    Transport Canada Civil Aviation (TCCA), which is the aviation 
authority for Canada, has issued TCCA AD CF-2009-29R4, dated October 1, 
2021 (TCCA AD CF-2009-29R4) (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-2021-1064.
    This AD was prompted by reports of a certain bolt at the pivot pin 
link being found missing or having stress corrosion cracking. The FAA 
is issuing this AD to address failure of the pivot pin retention bolt, 
which could result in a loss of directional control or loss of an NLG 
tire during takeoff or landing. 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 
84-32-167, dated August 12, 2021. This service information describes 
procedures for repetitive lubrications of the trailing arm of the NLG, 
which include a general visual inspection of the NLG pivot pin 
mechanism for discrepancies (i.e., bolt part number (P/N) NAS602-14D is 
missing or has damage (e.g., stress corrosion or stress corrosion 
cracking)) and replacement of missing or damaged bolts.
    De Havilland Aircraft of Canada Limited has also issued Temporary 
Revision ALI-0223, dated October 15, 2020. This service information 
describes new and revised airworthiness limitations, including life 
limits for certain bolts as specified in Structures Safe Life Task 32-
21-01-701 and Task 32-21-01-702.
    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 issuing this AD 
because the FAA evaluated all pertinent information and determined the 
unsafe condition exists and is likely to exist or develop on other 
products of the same type design.

Requirements of This AD

    This AD requires accomplishing the actions described previously for 
De Havilland Aircraft of Canada Limited Service Bulletin 84-32-167, 
dated August 12, 2021. This AD also requires revising the existing 
maintenance or inspection program to include new and revised 
airworthiness limitations (life limits for certain bolts).

Differences Between This AD and the MCAI or Service Information

    Part I of TCCA AD CF-2009-29R4 requires a modification to the NLG 
shock strut assembly within 1,600 flight cycles or 9 months for certain 
airplanes. The FAA is currently considering requiring the modification 
in order to address the identified unsafe condition. However, the 
planned compliance time for the installation of the modification would 
allow enough time to provide notice and opportunity for prior public 
comment on the merits of the modification. Therefore, this AD does not 
include the modification.
    Part III of TCCA AD CF 2009-29R4 applies to all airplanes but 
specifies to do the actions using De Havilland Aircraft of Canada 
Service Bulletin 84-32-167, dated August 12, 2021. The service 
information only has instructions for pivot pin retention bolt P/N 
NAS6204-14D. Therefore, the repetitive lubrications specified in (i) of 
this AD is for airplanes with pivot pin

[[Page 72176]]

retention bolt P/N NAS6204-14D installed on the NLG assembly.

Explanation of Change to the Applicability

    AD 2017-19-09 did not include serial number (S/N) 4002 in its 
applicability but it did identify Model DHC-8-400 airplanes in the 
applicability. However, the only Model DHC-8-400 airplane is S/N 4002, 
making the reference to Model DHC-8-400 unnecessary. In addition, the 
Model DHC-8-400 airplane is not included in TCCA AD CF-2009-29R4. 
Therefore, this AD does not apply to the Model DHC-8-400 airplane.
    In addition, the FAA has revised the applicability of this AD to 
identify model designations as published in the most recent type 
certificate data sheet for the affected models.

FAA's Justification and Determination of the Effective Date

    An unsafe condition exists that requires the immediate adoption of 
this AD without providing an opportunity for public comments prior to 
adoption. The FAA has found that the risk to the flying public 
justifies waiving notice and comment prior to adoption of this rule 
because failure of the pivot pin retention bolt could result in a loss 
of directional control or loss of a NLG tire during takeoff or landing, 
which could lead to runway excursions. In addition, the compliance time 
for the required action is shorter than the time necessary for the 
public to comment and for publication of the final rule. Therefore, the 
FAA finds good cause that notice and opportunity for prior public 
comment are impracticable. In addition, for the reasons stated above, 
the FAA finds that good cause exists for making this amendment 
effective in less than 30 days.

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this AD. Send your comments to an address listed under 
ADDRESSES. Include ``Docket No. FAA-2021-1064; Project Identifier MCAI-
2021-01028-T'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the final rule, 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 
this final rule 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 final rule.

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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to 
Antariksh Shetty, Aerospace Engineer, Airframe and Propulsion Section, 
FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 
11590; telephone 516-228-7300; 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.

Interim Action

    The FAA considers this AD interim action. The FAA is currently 
considering requiring the modification to the NLG shock strut assembly 
specified in Part I of TCCA AD CF-2009-29R4.

Regulatory Flexibility Act (RFA)

    The requirements of the RFA do not apply when an agency finds good 
cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and 
comment. Because the FAA has determined that it has good cause to adopt 
this rule without notice and comment, RFA analysis is not required.

Costs of Compliance

    The FAA estimates that this AD affects 54 airplanes of U.S. 
registry.
    The FAA estimates the following costs to comply with this AD:

                                      Estimated Costs for Required Actions
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                                                                                     Cost per      Cost on U.S.
              Action                      Labor cost             Parts cost           product        operators
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New actions.......................  1 work-hour x $85 per  Negligible...........             $85          $4,590
                                     hour = $85.
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* Table does not include estimated costs for revising the maintenance or inspection program.

    The FAA has determined that revising the maintenance or inspection 
program takes an average of 90 work-hours per operator, although the 
FAA recognizes that this number may vary from operator to operator. In 
the past, the FAA has estimated that this action takes 1 work-hour per 
airplane. Since operators incorporate maintenance or inspection program 
changes for their affected fleet(s), the FAA has determined that a per-
operator estimate is more accurate than a per-airplane estimate. 
Therefore, the FAA estimates the total cost per operator to be $7,650 
(90 work-hours x $85 per work-hour).
    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
------------------------------------------------------------------------
                                                             Cost per
              Labor cost                   Parts cost        product
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2 work-hours x $85 per hour = $170....              $8             $178
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[[Page 72177]]

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 AD will not have federalism 
implications under Executive Order 13132. This AD will 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 that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866, and
    (2) Will not affect intrastate aviation in Alaska.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 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:
0
a. Removing Airworthiness Directive (AD) 2017-19-09, Amendment 39-19039 
(82 FR 43829, September 20, 2017); and
0
b. Adding the following new AD:

2021-25-12 De Havilland Aircraft of Canada Limited (Type Certificate 
Previously Held by Bombardier, Inc.): Amendment 39-21856; Docket No. 
FAA-2021-1064; Project Identifier MCAI-2021-01028-T.

(a) Effective Date

    This airworthiness directive (AD) is effective January 5, 2022.

(b) Affected ADs

    This AD replaces AD 2017-19-09, Amendment 39-19039 (82 FR 43829, 
September 20, 2017) (AD 2017-19-09).

(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 and subsequent.

(d) Subject

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

(e) Reason

    This AD was prompted by reports of a certain bolt at the pivot 
pin link being found missing or having stress corrosion cracking. 
The FAA is issuing this AD to address failure of the pivot pin 
retention bolt, which could result in a loss of directional control 
or loss of a nose landing gear (NLG) tire during takeoff or landing, 
which could lead to runway excursions.

(f) Compliance

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

(g) Maintenance or Inspection Program Revision

    For airplanes with pivot pin retention bolt part number (P/N) 
NAS6204-14D installed on the NLG assembly: Within 30 days after the 
effective date of this AD, or within 30 days after installation of 
pivot pin retention bolt part number P/N NAS6204-14D, whichever 
occurs later, revise the existing maintenance or inspection program, 
as applicable, to incorporate the information for Structures Safe 
Life Task 32-21-01-701 and Task 32-21-01-702, as specified in De 
Havilland Aircraft of Canada Limited Temporary Revision ALI-0223, 
dated October 15, 2020. The initial compliance time for doing the 
tasks is at the applicable time specified in De Havilland Aircraft 
of Canada Limited Temporary Revision ALI-0223, dated October 15, 
2020, or within 30 days after the effective date of this AD, 
whichever occurs later; except, if replacement of bolt P/N NAS6204-
14D was performed before the effective date of this AD as specified 
in De Havilland Aircraft of Canada Service Bulletin 84-32-161, the 
initial compliance time for Task 32-21-01-702 (bolt P/N NAS6204-14D 
replacement) is within 3 months after the effective date of this AD 
or within 800 flight cycles after performing the replacement, 
whichever occurs later.

(h) No Alternative Actions or Intervals

    After the existing maintenance or inspection program has been 
revised as required by paragraph (g) of this AD, no alternative 
actions (e.g., replacements) or intervals may be used unless the 
actions and intervals are approved as an alternative method of 
compliance (AMOC) in accordance with the procedures specified in 
paragraph (j)(1) of this AD.

(i) Repetitive Lubrications

    For airplanes with pivot pin retention bolt P/N NAS6204-14D 
installed on the NLG assembly: Within 30 days or 400 flight cycles, 
whichever occurs first after the effective date of this AD, and 
thereafter at intervals not exceeding 400 flight cycles, lubricate 
the trailing arm of the NLG, including doing a general visual 
inspection of the NLG pivot pin mechanism for discrepancies (i.e., 
bolt P/N NAS602-14D is missing or has damage (e.g., stress corrosion 
or stress corrosion cracking)) and, as applicable, replacing the 
bolt before further flight, in accordance with paragraph 3.B. of the 
Accomplishment Instructions of De Havilland Aircraft of Canada 
Limited Service Bulletin 84-32-167, dated August 12, 2021.

(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-2009-29R4, dated October 1, 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-2021-1064.
    (2) For more information about this AD, contact Antariksh 
Shetty, Aerospace Engineer, Airframe and Propulsion Section, FAA, 
New York ACO Branch, 1600 Stewart

[[Page 72178]]

Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; fax 
516-794-5531; email [email protected].

(l) 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-
32-167, dated August 12, 2021.
    (ii) De Havilland Aircraft of Canada Limited Temporary Revision 
ALI-0223, dated October 15, 2020.
    (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.
    (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 Administration 
(NARA). For information on the availability of this material at 
NARA, email [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on December 3, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.

[FR Doc. 2021-27709 Filed 12-17-21; 11:15 am]
BILLING CODE 4910-13-P


