
[Federal Register Volume 88, Number 205 (Wednesday, October 25, 2023)]
[Proposed Rules]
[Pages 73265-73268]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-23516]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-2001; Project Identifier MCAI-2023-00666-T]
RIN 2120-AA64


Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 
2021-20-13, which applies to certain Bombardier, Inc., Model CL-600-
2B16 (604 Variant) airplanes. AD 2021-20-13 requires repetitive 
lubrication and repetitive detailed visual inspections (DVI) and non-
destructive test (NDT) inspections of the main landing gear (MLG) shock 
strut lower pins, and replacement if necessary. Since the FAA issued AD 
2021-20-13, Bombardier, Inc. developed a new design solution for this 
potential failure. This proposed AD would continue to require the 
lubrication and inspections specified in AD 2021-20-13 until the MLG 
shock strut assembly is modified by replacing the trailing arm bushing 
and installing new dynamic joint components. 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 
11, 2023.

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-2023-2001; 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 Incorporated by Reference:
     For service information identified in this NPRM, contact 
Bombardier, Inc., 200 C[ocirc]te-Vertu Road West, Dorval, Qu[eacute]bec 
H4S 2A3, Canada; North America toll-free telephone 1-866-538-1247 or 
direct-dial telephone 1-514-855-2999; email bombardier.com">ac.yul@aero.bombardier.com; 
website bombardier.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.

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:

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-2023-2001; Project Identifier 
MCAI-2023-00666-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 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 
Gabriel Kim, Aviation Safety Engineer, FAA, 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

    The FAA issued AD 2021-20-13, Amendment 39-21751 (86 FR 57033, 
October 14, 2021) (AD 2021-20-13), for certain Bombardier, Inc., CL-
600-2B16 (604 Variant) airplanes. AD 2021-20-13 was prompted by an MCAI 
originated by Transport Canada, which is the aviation authority for 
Canada. Transport Canada issued AD CF-2020-54R1, dated December 23, 
2020 (Transport Canada AD CF-2020-54R1), to correct an unsafe condition 
identified as cracking of the MLG shock strut lower pin part number 
19146-3. Transport Canada AD CF-2020-54R1 states that friction torque, 
when the shock strut is under compression loading, causes the pin anti-
rotation tangs to become loaded beyond their load carrying capability. 
According to Transport Canada, this overload condition can result in 
pin fracture originating at the base of the pin anti-rotation tang and 
is aggravated by inadequate lubrication.
    AD 2021-20-13 requires repetitively lubricating, repetitively 
inspecting (DVI and NDT inspections for cracking and damage, including 
fracture of the MLG shock strut lower pin at the pin rotation tang 
location), and replacing the MLG shock strut lower pin if there is any

[[Page 73266]]

cracking or damage as a result of the inspections. The FAA issued AD 
2021-20-13 to address cracking of the MLG shock strut lower pin. If not 
addressed, this condition could result in structural failure of one or 
both MLG.

Actions Since AD 2021-20-13 Was Issued

    Since the FAA issued AD 2021-20-13, Transport Canada superseded 
Transport Canada AD CF-2020-54R1 and issued Transport Canada AD CF-
2023-32, dated May 9, 2023 (referred to after this as ``the MCAI''). 
The MCAI states there is a new design solution for this potential 
failure of the shock strut lower pin, which involves replacing the 
training arm bushings at the attachment and reassembly of the MLG shock 
strut assembly to training arm assembly joint with new dynamic joint 
components. As a result, the MCAI requires this new design as 
terminating action for the requirements of Transport Canada AD CF-2020-
54R1.
    Bombardier, Inc. also reduced the range of one group of applicable 
aircraft from serial numbers 6050 through 6999 to 6050 through 6188. 
Bombardier, Inc. advises that subsequent aircraft are scheduled to have 
the new design completed in production. Therefore, the FAA has revised 
the applicability of this proposed AD accordingly.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2023-2001.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Bombardier, Inc., service information:
     Service Bulletin 604-32-031, dated December 29, 2022.
     Service Bulletin 605-32-008, dated December 29, 2022.
     Service Bulletin 650-32-005, dated December 29, 2022.
    This service information contains procedures for disassembling the 
left- and right-hand MLG shock strut and trailing arm joint, replacing 
the trailing arm bushings at the attachment, and re-assembling the 
joint with new dynamic joint components. These documents are distinct 
since they apply to different airplane configurations.
    This proposed AD would also require the following Bombardier, Inc., 
service information, which the Director of the Federal Register 
approved for incorporation by reference as of November 18, 2021 (86 FR 
57033, October 14, 2021):
     Service Bulletin 604-32-030, dated June 30, 2020.
     Service Bulletin 605-32-007, dated June 30, 2020.
     Service Bulletin 650-32-004, dated June 30, 2020.
    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 this State of Design Authority, it 
has notified the FAA of the unsafe condition described in the MCAI and 
service information referenced above. The FAA is issuing this NPRM 
after determining that 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 retain all of the requirements of AD 2021-
20-13 until the MLG shock strut assembly to trailing arm assembly joint 
is modified by accomplishing the actions specified in the service 
information described previously.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 433 airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Lubrication and inspections        7 work-hours x $85               $0  $595 per cycle.....  $257,635 per cycle.
 (retained actions from AD 2021-    per hour = $595.
 20-13).
Modification and testing (new      9 work-hours x $85            2,435  3,200..............  1,385,600.
 proposed actions).                 per hour = $765.
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    The FAA estimates the following costs to do any necessary on-
condition replacement that would be required based on the results of 
the repetitive inspections. The FAA has no way of determining the 
number of aircraft that might need this on-condition action:

               Estimated Costs of On-Condition Replacement
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                                                             Cost per
              Labor cost                   Parts cost        product
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6 work-hours x $85 per hour = $510....          $2,435           $2,945
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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

[[Page 73267]]

develop on products identified in this rulemaking action.

Regulatory Findings

    The FAA has 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) 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 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:
0
a. Removing Airworthiness Directive 2021-20-13, Amendment 39-21751 (86 
FR 57033, October 14, 2021); and
0
b. Adding the following new Airworthiness Directive:

Bombardier, Inc.: Docket No. FAA-2023-2001; Project Identifier MCAI-
2023-00666-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by December 11, 2023.

(b) Affected ADs

    This AD replaces AD 2021-20-13, Amendment 39-21751 (86 FR 57033, 
October 14, 2021) (AD 2021-20-13).

(c) Applicability

    This AD applies to Bombardier, Inc., Model CL-600-2B16 (604 
Variant) airplanes, serial numbers (S/N) 5301 through 5665 
inclusive, 5701 through 5988 inclusive, and 6050 through 6188 
inclusive, certificated in any category.

(d) Subject

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

(e) Reason

    This AD was prompted by reports of cracking of the main landing 
gear (MLG) shock strut lower pin. The FAA is issuing this AD to 
address cracking of the MLG shock strut lower pin. The unsafe 
condition, if not addressed, could result in structural failure of 
one or both MLG.

(f) Compliance

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

(g) Retained Repetitive Lubrication, With Revised Applicability

    This paragraph restates the requirements of paragraph (g) of AD 
2021-20-13, with revised applicability. Within 200 flight hours (FH) 
or 12 months after November 18, 2021 (the effective date of AD 2021-
20-13), whichever occurs first, lubricate the left-hand (LH) and 
right-hand (RH) MLG shock strut lower pins having part number (P/N) 
19146-3, in accordance with paragraph 2.B., ``Part A,'' of the 
Accomplishment Instructions of the applicable service bulletin, as 
specified in paragraphs (g)(1) through (3) of this AD. Repeat 
thereafter at intervals not to exceed 200 FH or 12 months, whichever 
occurs first.
    (1) For airplanes having S/N 5301 through 5665 inclusive: 
Bombardier Service Bulletin 604-32-030, dated June 30, 2020.
    (2) For airplanes having S/N 5701 through 5988 inclusive: 
Bombardier Service Bulletin 605-32-007, dated June 30, 2020.
    (3) For airplanes having S/N 6050 through 6188 inclusive: 
Bombardier Service Bulletin 650-32-004, dated June 30, 2020.

(h) Retained Detailed Visual Inspections (DVI), With No Changes

    This paragraph restates the requirements of paragraph (h) of AD 
2021-20-13, with no changes. At the applicable compliance time 
specified in paragraphs (h)(1) through (3) of this AD, perform the 
DVI for cracking and damage of the LH and RH MLG shock strut lower 
pins having part number (P/N) 19146-3, in accordance with paragraph 
2.C., ``Part B,'' of the Accomplishment Instructions of the 
applicable service bulletin, as specified in paragraphs (g)(1) 
through (3) of this AD. Repeat thereafter at intervals not to exceed 
400 FH or 24 months, whichever occurs first. If the DVI coincides 
with a non-destructive testing (NDT) inspection required by 
paragraph (i) of this AD, the NDT inspection supersedes the DVI for 
that interval only. If the accumulated flight cycles (FC) of the MLG 
shock strut lower pin are not known, use the related MLG assembly 
accumulated FC to determine when to accomplish the actions required 
by this paragraph.
    (1) For airplanes with an original airworthiness certificate or 
original export certificate of airworthiness issued on or before 
November 18, 2021 (the effective date of AD 2021-20-13) and on which 
an MLG shock strut lower pin has accumulated fewer than 600 total FC 
on the pin as of November 18, 2021: Before the accumulation of 750 
total FC on the pin.
    (2) For airplanes with an original airworthiness certificate or 
original export certificate of airworthiness issued on or before 
November 18, 2021 (the effective date of AD 2021-20-13) and on which 
an MLG shock strut lower pin has accumulated 600 total FC or more on 
the pin as of November 18, 2021: Within 150 FC after November 18, 
2021.
    (3) For airplanes with an original airworthiness certificate or 
original export certificate of airworthiness issued after November 
18, 2021 (the effective date of AD 2021-20-13): Before the 
accumulation of 750 total FC.

(i) Retained NDT Inspection, With No Changes

    This paragraph restates the requirements of paragraph (i) of AD 
2021-20-13, with no changes. At the applicable compliance time 
specified in paragraphs (i)(1) through (4) of this AD: Perform the 
NDT inspection for cracking and damage of the LH and RH MLG shock 
strut lower pins having P/N 19146-3, in accordance with paragraph 
2.D., ``Part C,'' of the Accomplishment Instructions of the 
applicable service bulletin, as specified in paragraphs (g)(1) 
through (3) of this AD. Repeat thereafter at intervals not to exceed 
900 FC. If the accumulated FC of the MLG shock strut lower pin is 
not known, use the related MLG assembly accumulated FC to determine 
when to accomplish the actions required by this paragraph.
    (1) For airplanes with an original airworthiness certificate or 
original export certificate of airworthiness issued on or before 
November 18, 2021 (the effective date of AD 2021-20-13) and on which 
an MLG shock strut lower pin has accumulated fewer than 1,200 total 
FC on the pin as of November 18, 2021: Before the accumulation of 
1,500 total FC on the pin.
    (2) For airplanes with an original airworthiness certificate or 
original export certificate of airworthiness issued on or before 
November 18, 2021 (the effective date of AD 2021-20-13) and on which 
an MLG shock strut lower pin has accumulated 1,200 total FC or more 
but fewer than 2,000 total FC on the pin as of November 18, 2021: 
Within 300 FC after November 18, 2021, or before the accumulation of 
2,200 total FC on the pin, whichever occurs first.
    (3) For airplanes with an original airworthiness certificate or 
original export certificate of airworthiness issued on or before 
November 18, 2021 (the effective date of AD 2021-20-13) and on which 
an MLG shock strut lower pin that has accumulated 2,000 total FC or 
more on the pin as of November 18, 2021: Within 200 FC after 
November 18, 2021.
    (4) For airplanes with an original airworthiness certificate or 
original export certificate of airworthiness issued after November 
18, 2021 (the effective date of AD 2021-20-13): Before the 
accumulation of 1,500 total FC.

(j) Retained Replacement, With No Changes

    This paragraph restates the requirements of paragraph (j) of AD 
2021-20-13, with no changes. If, during any inspection required by 
this AD, any crack or damage of the MLG

[[Page 73268]]

shock strut lower pin is detected, before further flight, replace 
the affected MLG shock strut lower pin with a new part in accordance 
with paragraph 2.E., ``Part D,'' of the Accomplishment Instructions 
of the applicable service bulletin, as specified in paragraphs 
(g)(1) through (3) of this AD.

(k) New Requirement of This AD: Modification

    Within 60 months from the effective date of this AD, modify the 
LH and RH MLG assembly in accordance with paragraph 2.B. of the 
Accomplishment Instructions of the applicable service bulletin, as 
specified in paragraphs (k)(1) through (3) of this AD.
    (1) For airplanes having S/N 5301 through 5665 inclusive: 
Bombardier Service Bulletin 604-32-031, dated December 29, 2022.
    (2) For airplanes having S/N 5701 through 5988 inclusive: 
Bombardier Service Bulletin 605-32-008, dated December 29, 2022.
    (3) For airplanes having S/N 6050 through 6188 inclusive: 
Bombardier Service Bulletin 650-32-005, dated December 29, 2022.

(l) New Requirement of the AD: Testing

    Before further flight after completing paragraph (k) of this AD, 
perform the testing of the MLG shock strut assembly to trailing arm 
assembly joint in accordance with paragraph 2.C. of the 
Accomplishment Instructions of the applicable service bulletin, as 
specified in paragraphs (k)(1) through (3) of this AD.

(m) Terminating Action

    Modifying and testing an airplane as required by paragraphs (k) 
and (l) of this AD terminates the initial and repetitive lubrication 
and inspections required by paragraphs (g), (h), and (i) of this AD 
for that airplane.

(n) Additional AD Provisions

    (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 the address identified 
in paragraph (o)(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 Bombardier, Inc.'s 
Transport Canada Design Approval Organization (DAO). If approved by 
the DAO, the approval must include the DAO-authorized signature.

(o) Additional Information

    (1) Refer to Transport Canada AD CF-2023-32, dated May 9, 2023, 
for related information. This Transport Canada AD may be found in 
the AD docket at regulations.gov under Docket No. FAA-2023-2001.
    (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].

(p) 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.
    (3) The following service information was approved for IBR on 
[DATE 35 DAYS AFTER PUBLICATION OF THE FINAL RULE].
    (i) Bombardier Service Bulletin 604-32-031, dated December 29, 
2022.
    (ii) Bombardier Service Bulletin 605-32-008, dated December 29, 
2022.
    (iii) Bombardier Service Bulletin 650-32-005, dated December 29, 
2022.
    (4) The following service information was approved for IBR on 
November 18, 2021 (86 FR 57033, October 14, 2021).
    (i) Bombardier Service Bulletin 604-32-030, dated June 30, 2020.
    (ii) Bombardier Service Bulletin 605-32-007, dated June 30, 
2020.
    (iii) Bombardier Service Bulletin 650-32-004, dated June 30, 
2020.
    (5) For service information identified in this AD, contact 
Bombardier, Inc., 200 C[ocirc]te-Vertu Road West, Dorval, 
Qu[eacute]bec H4S 2A3, Canada; North America toll-free telephone 1-
866-538-1247 or direct-dial telephone 1-514-855-2999; email 
bombardier.com">ac.yul@aero.bombardier.com; website bombardier.com.
    (6) 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.
    (7) You may view this material at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on October 19, 2023.
Ross Landes,
Deputy Director for Regulatory Operations, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2023-23516 Filed 10-24-23; 8:45 am]
BILLING CODE 4910-13-P


