
[Federal Register Volume 88, Number 160 (Monday, August 21, 2023)]
[Rules and Regulations]
[Pages 56753-56756]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-17777]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1047; Project Identifier MCAI-2022-01601-T; 
Amendment 39-22524; AD 2023-16-05]
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: Final rule.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and -
402 airplanes. This AD was prompted by reports of the main landing gear 
(MLG) aft door not opening when using the alternate extension system. 
This AD requires a one-time inspection of the spring box assembly, 
repetitive inspections of the cam assembly and alternate release cable 
assembly, corrective actions if necessary, and a replacement of certain 
alternate release cable assemblies. In addition, this AD requires 
certain aircraft maintenance manuals tasks when installing the cam 
assembly or alternate release cable assembly. This AD also prohibits 
the installation of affected parts. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective September 25, 2023.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of September 25, 
2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-1047; 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, the mandatory continuing airworthiness 
information (MCAI), 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.
    Material Incorporated by Reference:
     For service information identified in this final rule, 
contact De Havilland Aircraft of Canada Limited, Dash 8 Series Customer 
Response Centre, 5800 Explorer Drive, Mississauga, Ontario, L4W 5K9, 
Canada; telephone North America (toll-free): 855-310-1013, Direct: 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 Street, Des Moines, WA. For information on the availability of 
this material at the FAA, call 206-231-3195. It is also available at 
regulations.gov under Docket No. FAA-2023-1047.

FOR FURTHER INFORMATION CONTACT: Gabriel Kim, Aviation Safety Engineer, 
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-
228-7300; email [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    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 (Type Certificate Previously Held by 
Bombardier, Inc.) Model DHC-8-401 and -402 airplanes. The NPRM 
published in the Federal Register on June 1, 2023 (88 FR 35788). The 
NPRM was prompted by AD CF-2022-69, dated December 16, 2022, issued by 
Transport Canada, which is the aviation authority for Canada (referred 
to after this as the MCAI). The MCAI states that several instances 
occurred where the maintenance crew using the MLG alternate extension 
system did not open the MLG aft doors. An investigation found that the 
associated cam assembly failed due to a fractured cam assembly lever, a 
damaged spring box assembly, or a broken alternate release cable 
assembly.
    In the NPRM, the FAA proposed to require a one-time inspection of 
the spring box assembly, repetitive inspections of the cam assembly and 
alternate release cable assembly, corrective actions if necessary, and 
a replacement of certain alternate release cable assemblies. In 
addition, the NPRM also proposed to require certain aircraft 
maintenance manuals tasks when installing the cam assembly or alternate 
release cable assembly. The NPRM also proposed to prohibit the 
installation of affected parts. The FAA is issuing this AD to address 
possible cam assembly, spring box assembly, and alternate release cable 
assembly failures. The unsafe condition, if not addressed, could result 
in asymmetric main landing gear configuration at landing, and a runway 
excursion.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2023-1047.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from Air Line Pilots Association, 
International (ALPA) who supported the NPRM without change.

Conclusion

    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 this State of Design Authority, it 
has notified the FAA of the unsafe condition described in the MCAI 
referenced above. The FAA reviewed the relevant data, considered the 
comments received, and determined that air safety requires adopting 
this AD as proposed. Accordingly, the FAA is issuing this AD to address 
the unsafe condition on this product. Except for minor editorial 
changes, this AD is adopted as proposed in the NPRM. None of the 
changes will increase the economic burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed De Havilland Aircraft of Canada Limited Service 
Bulletin 84-32-159, dated June 28, 2019. This service information 
specifies procedures for performing a general visual inspection of the 
cam assembly (part number (P/N) 48510-5) for discrepancies (such as the 
cam assembly does not return to its original rested position, or signs 
of an increased gap between the roller and the cam guide); a general 
visual inspection of the alternate release cable assembly (or uplock 
cable assembly) (P/N 48503-3) for discrepancies (such as a broken 
cable); a one-time general visual inspection for discrepancies (such as 
any bend on the plunger) of the left and right MLG spring box assembly 
(P/N 48504-1); and corrective actions. Corrective actions include 
replacing the cam assembly with a new cam assembly, replacing the 
alternate release cable assembly with a new alternate release cable 
assembly, and replacing

[[Page 56754]]

the spring box assembly with a new spring box assembly.
    The FAA also reviewed De Havilland Aircraft of Canada Limited 
Service Bulletin 84-32-172, dated August 16, 2022, including Collins 
Aerospace Service Bulletin 48500-32-152, dated July 18, 2022. This 
service information specifies procedures for replacing the left and 
right MLG alternate release cable assemblies, P/N 48503-3, with the 
redesigned alternate release cable assembly, P/N 48503-5.
    The FAA also reviewed De Havilland Aircraft of Canada Limited 
Temporary Revision 32-603, dated December 1, 2022, which describes 
aircraft maintenance manual (AMM) TASK 32-34-16-400-804, ``Installation 
of the Alternate Extension Cables-Center Fuselage to Nacelle.''
    The FAA also reviewed AMM TASK 32-34-26-400-801, ``Installation of 
the MLG Alternate-Extension Cam-Mechanism Assembly'' of Subject 32-34-
26, ``Cam Mechanism Assembly-MLG Alternative Extension'' in Chapter 32, 
``Landing Gear,'' of the De Havilland Aircraft of Canada Limited 
Aircraft Maintenance Manual, Revision 76, dated March 5, 2022. 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 affects 55 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
              Labor cost                  Parts cost        Cost per product          Cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
Up to 5 work-hour x $85 per hour =             $4,780   Up to $5,205............  Up to $286,275.
 $425.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary on-
condition action that would be required based on the results of any 
required action. The FAA has no way of determining the number of 
aircraft that might need this on-condition action:

                 Estimated Costs of On-Condition Actions
------------------------------------------------------------------------
                                                             Cost per
              Labor cost                   Parts cost        product
------------------------------------------------------------------------
4.5 work-hours x $85 per hour = $383..         $41,328          $41,711
------------------------------------------------------------------------

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

    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,
    (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.

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:

2023-16-05 De Havilland Aircraft of Canada Limited (Type Certificate 
Previously Held by Bombardier, Inc.): Amendment 39-22524; Docket No. 
FAA-2023-1047; Project Identifier MCAI-2022-01601-T.

(a) Effective Date

    This airworthiness directive (AD) is effective September 25, 
2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to De Havilland Aircraft of Canada Limited (type 
certificate previously held by Bombardier, Inc.) Model DHC-8-401 and 
-402 airplanes, certificated in any category, having serial numbers 
4001 and 4003 through 4633 inclusive.

(d) Subject

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

[[Page 56755]]

(e) Unsafe Condition

    This AD was prompted by reports of the main landing gear (MLG) 
aft door not opening when using the alternate extension system. The 
FAA is issuing this AD to address possible cam assembly, spring box 
assembly, and alternate release cable assembly failures. The unsafe 
condition, if not addressed, could result in asymmetric MLG 
configuration at landing, and a runway excursion.

(f) Compliance

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

(g) One-Time Inspection

    Within 2,400 flight hours or 12 months, whichever occurs first, 
after the effective date of this AD, do a one-time general visual 
inspection for discrepancies on the left and right MLG spring box 
assemblies (part number (P/N) 48504-1), in accordance with Section 
3.B., Part A, of the Accomplishment Instructions of De Havilland 
Aircraft of Canada Limited Service Bulletin 84-32-159, dated June 
28, 2019. If any discrepancy is discovered in the spring box 
assembly, before further flight, replace with a new spring box 
assembly, in accordance with Section 3.B. Part B, of the 
Accomplishment Instructions of De Havilland Aircraft of Canada 
Limited Service Bulletin 84-32-159, dated June 28, 2019.

(h) Repetitive Inspections

    (1) Within 2,400 flight hours or 12 months, whichever occurs 
first, after the effective date of this AD, do a general visual 
inspection for discrepancies of the cam assemblies (P/N 48510-5) on 
the left and right MLG, in accordance with Section 3.B. Part A, of 
the Accomplishment Instructions of De Havilland Aircraft of Canada 
Limited Service Bulletin 84-32-159, dated June 28, 2019. Thereafter, 
repeat the inspection at intervals not to exceed 2,400 flight hours 
or 12 months, whichever occurs first. If any discrepancy is 
discovered in the cam assembly, before further flight, replace with 
a new cam assembly, in accordance with Section 3.B. Part B, of the 
Accomplishment Instructions of De Havilland Aircraft of Canada 
Limited Service Bulletin 84-32-159, dated June 28, 2019.
    (2) Within 2,400 flight hours or 12 months, whichever occurs 
first, after the effective date of this AD, do a general visual 
inspection for discrepancies of the alternate release cable 
assemblies (P/N 48503-3) on the left and right MLG, in accordance 
with Section 3.B., Part A, of the Accomplishment Instructions of De 
Havilland Aircraft of Canada Limited Service Bulletin 84-32-159, 
dated June 28, 2019. Thereafter, repeat the inspection at intervals 
not to exceed 2,400 flight hours or 12 months, whichever occurs 
first. If any discrepancy is found, before further flight, replace 
the alternate release cable assembly with a redesigned alternate 
release cable assembly P/N 48503-5, in accordance with Section 3.B. 
of the Accomplishment Instructions of De Havilland Aircraft of 
Canada Limited Service Bulletin 84-32-172, dated August 16, 2022, 
including Collins Aerospace Service Bulletin 48500-32-152, dated 
July 18, 2022. Accomplishing the replacement required by paragraph 
(i) of this AD terminates the inspections required by this 
paragraph.

(i) Replacement

    Within 5,500 flight hours or 30 months, whichever occurs first, 
after the effective date of this AD, replace the left and right MLG 
alternate release cable assemblies, P/N 48503-3, with the redesigned 
alternate release cable assembly, P/N 48503-5, in accordance with 
Section 3.B. of the Accomplishment Instructions of De Havilland 
Aircraft of Canada Limited Service Bulletin 84-32-172, dated August 
16, 2022, including Collins Aerospace Service Bulletin 48500-32-152, 
dated July 18, 2022.

(j) Maintenance Task Requirement

    As of the effective date of this AD, when installing an MLG 
alternate extension system cam assembly and when installing an 
alternate release cable assembly, the following aircraft maintenance 
manual (AMM) tasks must be used, as applicable:
    (1) For the alternate release cable assembly: AMM TASK 32-34-16-
400-804, ``Installation of the Alternate Extension Cables-Center 
Fuselage to Nacelle'' as specified in De Havilland Aircraft of 
Canada Limited Temporary Revision 32-603, dated December 1, 2022.
    (2) For the MLG alternate extension system cam assembly: AMM 
TASK 32-34-26-400-801, ``Installation of the MLG Alternate-Extension 
Cam-Mechanism Assembly'' of Subject 32-34-26, ``Cam Mechanism 
Assembly-MLG Alternative Extension'' in Chapter 32, ``Landing 
Gear,'' of the De Havilland Aircraft of Canada Limited Aircraft 
Maintenance Manual, Revision 76, dated March 5, 2022.

(k) Parts Installation Prohibition

    As of the effective date of this AD, no person may install, on 
any airplane, an alternate release cable assembly P/N 48503-3.

(l) Additional AD Provisions

    The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, 
International Validation 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 
International Validation Branch, mail it to ATTN: Program Manager, 
Continuing Operational Safety, at the address identified in 
paragraph (m)(2) of this AD or email to: [email protected]. If 
mailing information, also submit information by email. 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, International 
Validation Branch, FAA; or Transport Canada; or De Havilland 
Aircraft of Canada Limited's Transport Canada Design Approval 
Organization (DAO). If approved by the DAO, the approval must 
include the DAO-authorized signature.

(m) Additional Information

    (1) Refer to Transport Canada AD CF-2022-69, dated December 16, 
2022, for related information. This Transport Canada AD may be found 
in the AD docket at regulations.gov under Docket No. FAA-2023-1047.
    (2) For more information about this AD, contact Gabriel Kim, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; telephone 516-228-7300; email [email protected].

(n) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference 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-
32-159, dated June 28, 2019.
    (ii) De Havilland Aircraft of Canada Limited Service Bulletin 
84-32-172, dated August 16, 2022, including Collins Aerospace 
Service Bulletin 48500-32-152, dated July 18, 2022.
    Note 1 to paragraph (n)(2)(ii): De Havilland issued De Havilland 
Service Bulletin 84-32-172, dated August 16, 2022, with Collins 
Aerospace Service Bulletin 48500-32-152, dated July 18, 2022, 
attached as one ``merged'' file for the convenience of affected 
operators.
    (iii) De Havilland Aircraft of Canada Limited Temporary Revision 
32-603, dated December 1, 2022.
    (iv) AMM TASK 32-34-26-400-801, ``Installation of the MLG 
Alternate-Extension Cam-Mechanism Assembly,'' of Subject 32-34-26, 
``Cam Mechanism Assembly-MLG Alternative Extension'' in Chapter 32, 
``Landing Gear,'' of the De Havilland Aircraft of Canada Limited 
Aircraft Maintenance Manual, Revision 76, dated March 5, 2022.
    (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 North America (toll-free): 855-310-1013, Direct: 
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 Street, 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:

[[Page 56756]]

www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on August 7, 2023.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-17777 Filed 8-18-23; 8:45 am]
BILLING CODE 4910-13-P


