[Federal Register Volume 86, Number 196 (Thursday, October 14, 2021)]
[Rules and Regulations]
[Pages 57030-57033]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-22292]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0312; Project Identifier MCAI-2020-01376-T; 
Amendment 39-21729; AD 2021-19-11]
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.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain De Havilland Aircraft of Canada Limited Model DHC-8-102, -103, 
and -106 airplanes; Model DHC-8-201 and -202 airplanes; Model DHC-8-
301, -311, and -315 airplanes; and Model DHC-8-400, -401, and -402 
airplanes. This AD was prompted by reports that mounting nuts attaching 
the rudder actuator bracket to the vertical stabilizer have been found 
cracked or missing due to hydrogen embrittlement. This AD requires a 
one-time inspection of the rudder actuator bracket mounting nuts, and 
corrective actions if necessary. The FAA is issuing this AD to address 
the unsafe condition on these products.

DATES: This AD is effective November 18, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of November 18, 
2021.

ADDRESSES: 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 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-2021-0312.

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-
0312; 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 final rule, any comments received, and other information. The 
address for Docket Operations is U.S. Department of Transportation, 
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 
New Jersey Avenue SE, Washington, DC 20590.

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:

Background

    Transport Canada Civil Aviation (TCCA), which is the aviation 
authority for Canada, has issued TCCA AD CF-2020-34, dated October 6, 
2020 (TCCA AD CF-2020-34) (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-8-102, -103, and -106 airplanes; Model DHC-8-201 and -202 
airplanes; Model DHC-8-301, -311, -314, and -315 airplanes; and Model 
DHC-8-400, -401, and -402 airplanes. Model DHC-8-314 airplanes are not 
certificated by the FAA and are not included on the U.S. type 
certificate data sheet; this AD therefore does not include those 
airplanes in the applicability. You may examine the MCAI in the AD 
docket at https://www.regulations.gov by searching for and locating 
Docket No. FAA-2021-0312.
    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain De Havilland 
Aircraft of Canada Limited Model DHC-8-102, -103, and -106 airplanes; 
Model DHC-8-201 and -202 airplanes; Model DHC-8-301, -311, and -315 
airplanes; and Model DHC-8-400, -401, and -402 airplanes. The NPRM 
published in the Federal Register on April 20, 2021 (86 FR 20459). The 
NPRM was prompted by reports that mounting nuts attaching the rudder 
actuator bracket to the vertical stabilizer have been found cracked or 
missing due to hydrogen embrittlement. The NPRM proposed to require a 
one-time inspection of the rudder actuator bracket mounting nuts, and 
corrective actions if necessary. The FAA is issuing this AD to address 
the possible loss of the rudder actuator bracket, which could result in 
a dormant disconnection between the rudder actuator and the vertical 
stabilizer. This condition, if not addressed, could result in a loss of 
directional control of the aircraft. See the MCAI for additional 
background information.

Comments

    The FAA gave the public the opportunity to participate in 
developing this final rule. The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Support for the NPRM

    The Air Line Pilots Association, International (ALPA), indicated 
its support for the NPRM.

[[Page 57031]]

Request To Require Procedure Only

    Horizon Air requested that paragraph (g) of the proposed AD be 
changed to require only paragraph 3.B. (Procedure) of the 
Accomplishment Instructions of the applicable service information. 
Horizon stated that requiring paragraph 3.A. (Job Set-up) and paragraph 
3.C. (Close-Out) restricts an operator's ability to perform other 
maintenance in conjunction with the required actions.
    The FAA agrees with the request. Paragraph (g) of this AD has been 
changed to require only paragraph 3.B. (Procedure) of the 
Accomplishment Instructions of De Havilland Service Bulletin 8-27-123, 
Revision A, dated September 8, 2020; or Service Bulletin 84-27-74, 
Revision B, dated September 8, 2020; as applicable.

Request To Remove and Replace All Suspect Hardware

    A commenter suggested removal and replacement of ``all suspect 
hardware.'' The commenter asserted that hydrogen embrittlement would 
not be evident by way of visual inspection. The FAA infers a request to 
change the requirements of the proposed AD to replace all affected 
rudder actuator bracket mounting nuts instead of relying on an 
inspection to determine which mounting nuts need replacement.
    The FAA disagrees with the request. The FAA notes that the rudder 
actuator bracket mounting nuts were installed as required by AD 2012-
04-08, Amendment 39-16964 (77 FR 13193, March 6, 2012), which has a 
compliance time of within 6,000 flight hours or 3 years after April 10, 
2012, whichever occurs first. Viking confirmed that mounting nuts with 
hydrogen embrittlement can show cracking as soon as one week after 
being torqued. However, these airplanes have been flying for several 
years with the mounting nuts installed and without reports of loss of 
directional control of the airplane caused by the mounting nuts. TCCA 
and Viking therefore determined, and the FAA agrees, that a one-time 
visual inspection and replacement if necessary is sufficient to address 
the unsafe condition. This AD has not been changed with regard to this 
request.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety and the public interest 
require adopting this final rule with the change described previously 
and minor editorial changes. The FAA has determined that these minor 
changes:
     Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    The FAA also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this final 
rule.

Related Service Information Under 1 CFR Part 51

    De Havilland has issued Service Bulletin 8-27-123, Revision A, 
dated September 8, 2020; and Service Bulletin 84-27-74, Revision B, 
dated September 8, 2020. This service information specifies procedures 
for doing a detailed visual inspection of the nuts attaching the rudder 
actuator brackets to the rear spar. If the nuts are corroded, cracked, 
or otherwise damaged, or if they are missing, they are replaced. These 
documents are distinct since they apply to different airplane models. 
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.

Costs of Compliance

    The FAA estimates that this AD would affect 69 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.
                          Labor cost                              Parts cost        product         operators
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3 work-hours x $85 per hour = $255...........................              $0             $255          $17,595
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    The FAA estimates the following costs to do any necessary 
replacement that would be required based on the results of the 
inspection. The agency has no way of determining the number of aircraft 
that might need this replacement:

                                               On-Condition Costs
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                                                                                                     Cost per
                 Action                          Labor cost                  Parts cost               product
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Nut replacement........................  2 work-hours x $85 per     Minimal.....................            $170
                                          hour = $170.
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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

    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:

[[Page 57032]]

    (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.

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 adding the following new airworthiness 
directive:

2021-19-11 De Havilland Aircraft of Canada Limited (Type Certificate 
Previously Held by Bombardier, Inc.): Amendment 39-21729; Docket No. 
FAA-2021-0312; Project Identifier MCAI-2020-01376-T.

(a) Effective Date

    This airworthiness directive (AD) is effective November 18, 
2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to De Havilland Aircraft of Canada Limited (type 
certificate previously held by Bombardier, Inc.) airplanes, 
certificated in any category, and identified in paragraphs (c)(1) 
through (4) of this AD.
    (1) Model DHC-8-102, -103, and -106 airplanes, as identified in 
De Havilland Service Bulletin 8-27-123, Revision A, dated September 
8, 2020.
    (2) Model DHC-8-201 and -202 airplanes, as identified in De 
Havilland Service Bulletin 8-27-123, Revision A, dated September 8, 
2020.
    (3) Model DHC-8-301, -311, and -315 airplanes, as identified in 
De Havilland Service Bulletin 8-27-123, Revision A, dated September 
8, 2020.
    (4) Model DHC-8-400, -401, and -402 airplanes, as identified in 
De Havilland Service Bulletin 84-27-74, Revision B, dated September 
8, 2020.

(d) Subject

    Air Transport Association (ATA) of America Code 27, Flight 
controls.

(e) Unsafe Condition

    This AD was prompted by reports that mounting nuts attaching the 
rudder actuator bracket to the vertical stabilizer have been found 
cracked or missing due to hydrogen embrittlement. The FAA is issuing 
this AD to address the possible loss of the rudder actuator bracket, 
which could result in a dormant disconnection between the rudder 
actuator and the vertical stabilizer. This condition, if not 
addressed, could result in a loss of directional control of the 
aircraft.

(f) Compliance

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

(g) Required Actions

    Within 8,000 flight hours or 4 years, whichever is earlier, 
after the effective date of this AD: Do a detailed visual inspection 
of the rudder actuator bracket mounting nuts for missing nuts or 
corrosion, cracking, or other damage, in accordance with paragraph 
3.B. of the Accomplishment Instructions of De Havilland Service 
Bulletin 8-27-123, Revision A, dated September 8, 2020; or De 
Havilland Service Bulletin 84-27-74, Revision B, dated September 8, 
2020; as applicable. If any missing nuts or corrosion, cracking, or 
other damage is found, replace the nuts before further flight, in 
accordance with paragraph 3.B. of the Accomplishment Instructions of 
De Havilland Service Bulletin 8-27-123, Revision A, dated September 
8, 2020; or De Havilland Service Bulletin 84-27-74, Revision B, 
dated September 8, 2020; as applicable.

(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 Service Bulletin 8-27-123, dated 
December 20, 2019; De Havilland Service Bulletin 84-27-74, dated 
December 20, 2019; or De Havilland Service Bulletin 84-27-74, 
Revision A, dated January 20, 2020; as applicable.

(i) No Reporting Requirement

    Although De Havilland Service Bulletin 8-27-123, Revision A, 
dated September 8, 2020; and De Havilland Service Bulletin 84-27-74, 
Revision B, dated September 8, 2020, specify to submit certain 
information to the manufacturer, this AD does not include that 
requirement.

(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-2020-34, dated October 6, 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-2021-0312.
    (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) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (l)(3) and (4) of this AD.

(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 Service Bulletin 8-27-123, Revision A, dated 
September 8, 2020.
    (ii) De Havilland Service Bulletin 84-27-74, Revision B, dated 
September 8, 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.


[[Page 57033]]


    Issued on September 7, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-22292 Filed 10-13-21; 8:45 am]
BILLING CODE 4910-13-P