[Federal Register Volume 86, Number 146 (Tuesday, August 3, 2021)]
[Proposed Rules]
[Pages 41794-41798]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-16431]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0613; Project Identifier MCAI-2020-01431-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-8-400, -
401, and -402 airplanes. This proposed AD was prompted by a report of 
cracking found on a main landing gear (MLG) drag strut assembly. This 
proposed AD would require a records review to determine if an affected 
MLG drag strut assembly is installed, repetitive detailed inspections 
for cracking of affected strut assemblies, a one-time magnetic particle 
inspection for cracking, and on-condition actions 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 September 
17, 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.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0613; 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.

[[Page 41795]]


FOR FURTHER INFORMATION CONTACT: Aziz Ahmed, Aerospace Engineer, 
Airframe and Propulsion Section, FAA, New York ACO Branch, 1600 Stewart 
Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7329; fax 516-
794-5531; 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-2021-0613; Project Identifier 
MCAI-2020-01431-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 Aziz 
Ahmed, Aerospace Engineer, Airframe and Propulsion Section, FAA, New 
York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
telephone 516-228-7329; 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-2020-43, dated October 21, 
2020 (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 at 
https://www.regulations.gov by searching for and locating Docket No. 
FAA-2021-0613.
    This proposed AD was prompted by a report of cracking found on an 
MLG drag strut assembly. The MLG drag strut had accumulated a total of 
26,968 flight cycles and 12,392 flight hours since new, of which 2,830 
flight cycles and 1,420 flight hours had accumulated since the last 
overhaul. The last overhaul had been conducted one year prior to the 
crack finding. It is suspected that the cracking was caused by the 
clamping method used by the repair facility during the most recent 
overhaul, and was missed during subsequent non-destructive testing 
(NDT) inspections required as part of the refurbishment process. The 
FAA is proposing this AD to address cracking of the MLG drag strut 
assembly and possible failure under compression loads during landing or 
ground operations, which could result in asymmetric MLG configuration 
and potential runway excursion. See the MCAI for additional background 
information.

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 a records review to determine if an 
affected MLG drag strut assembly is installed, repetitive detailed 
inspections for cracking of affected strut assemblies, a one-time 
magnetic particle inspection for cracking, and on-condition actions if 
necessary. On-condition actions include replacing the MLG drag strut 
assembly and re-identifying the MLG drag strut assembly.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 34 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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              Labor cost                   Parts cost        Cost per product          Cost on U.S. operators
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Up to 11 work-hours x $85 per hour =                $0   Up to $935..............  Up to $31,790.
 Up to $935.
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    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:

[[Page 41796]]



                                     Estimated Costs of On-Condition Actions
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              Labor cost                   Parts cost        Cost per product          Cost on U.S. operators
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Up to 10 work-hours x $85 per hour =               $ *   Up to $850..............  Up to $850.
 Up to $850.
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* The FAA has received no definitive data that would enable the agency to provide parts cost estimates for the
  actions 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.

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-2021-0613; Project 
Identifier MCAI-2020-01431-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 17, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to De Havilland Aircraft of Canada Limited Model 
DHC-8-400, -401, and -402 airplanes, certificated in any category, 
serial numbers 4001, 4003, and subsequent.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a report of cracking found on a main 
landing gear (MLG) drag strut assembly. The FAA is issuing this AD 
to address cracking of the MLG drag strut assembly and possible 
failure under compression loads during landing or ground operations, 
which could result in asymmetric MLG configuration and potential 
runway excursion.

(f) Compliance

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

(g) Records Review, Repetitive Inspections, and On-Condition Actions

    Within 30 days after the effective date of this AD: Review the 
applicable airplane maintenance records to determine if any affected 
MLG drag strut assembly identified in figure 1 to the introductory 
text of paragraph (g) of this AD is installed. If any affected MLG 
drag strut assembly is installed, do the actions specified in 
paragraphs (g)(1) and (2) of this AD.
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[GRAPHIC] [TIFF OMITTED] TP03AU21.001

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    (1) Within 80 flight hours after accomplishing the records 
review required by paragraph (g) of this AD, do a detailed 
inspection for cracking of the affected MLG drag strut assembly, and 
do all applicable on-condition actions before further flight, in 
accordance with a method approved by the Manager, New York ACO 
Branch, FAA. Repeat the inspection thereafter at intervals not to 
exceed 80 flight hours until the magnetic particle inspection 
required by paragraph (g)(2) of this AD is done.
    Note 1 to paragraph (g)(1): Guidance on the inspections and on-
condition actions required by this AD can be found in Transport 
Canada Civil Aviation (TCCA) AD CF-2020-43, dated October 21, 2020.
    (2) Within 1,600 flight hours or 12 months after the effective 
date of this AD, whichever occurs first, perform a magnetic particle 
inspection for cracks of the entire tubular section of the affected 
MLG drag strut assembly, and do all on-condition actions before 
further flight, in accordance with a method approved by the Manager, 
New York ACO Branch, FAA. Performing the magnetic particle 
inspection required by this paragraph terminates the repetitive 
detailed inspections required by paragraph (g)(1) of this AD.

(h) Parts Installation Prohibition

    As of the effective date of this AD, no person may install an 
affected MLG drag strut assembly identified in figure 1 to the 
introductory text of paragraph (g) of this AD on any airplane unless 
the inspections and applicable on-conditions specified in paragraphs 
(g)(1) and (2) of this AD are done before further flight.

(i) 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.

(j) Related Information

    (1) Refer to Mandatory Continuing Airworthiness Information 
(MCAI) TCCA AD CF-2020-43, dated October 21, 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-2021-0613.
    (2) For more information about this AD, contact Aziz Ahmed, 
Aerospace Engineer, Airframe and Propulsion Section, FAA, New York 
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
telephone 516-228-7329; fax 516-794-5531; email [email protected].
    (3) For information about TCCA AD CF-2020-43, dated October 21, 
2020, contact

[[Page 41798]]

TCCA, Transport Canada National Aircraft Certification, 159 
Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada; telephone 888-663-
3639; email [email protected]; internet https://tc.canada.ca/en/aviation. 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 July 28, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.

[FR Doc. 2021-16431 Filed 8-2-21; 8:45 am]
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