[Federal Register Volume 89, Number 109 (Wednesday, June 5, 2024)]
[Proposed Rules]
[Pages 48139-48141]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-12045]


 ========================================================================
 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
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  Federal Register / Vol. 89, No. 109 / Wednesday, June 5, 2024 / 
Proposed Rules  

[[Page 48139]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-1479; Project Identifier MCAI-2023-00657-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 adopt a new airworthiness directive (AD) 
for certain Bombardier Inc. Model BD-100-1A10 airplanes. This proposed 
AD was prompted by a determination that a revised restrictive 
airworthiness limitation is necessary. This proposed AD would require 
revising the existing maintenance or inspection program, as applicable, 
to incorporate a revised restrictive airworthiness limitation for the 
aft engine mount attachment bolts. 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 July 22, 
2024.

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-2024-1479; 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 Business Aircraft Customer Response Center, 400 C[ocirc]te-
Vertu Road West, Dorval, Qu[eacute]bec H4S 1Y9, Canada; telephone 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 St., Des Moines, WA. For information on the availability of this 
material at the FAA, call 206-231-3195.

FOR FURTHER INFORMATION CONTACT: Yaser Osman, 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-2024-1479; Project Identifier 
MCAI-2023-00657-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 Yaser 
Osman, 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

    Transport Canada, which is the aviation authority for Canada, has 
issued Transport Canada AD CF-2023-29, dated May 5, 2023 (Transport 
Canada AD CF-2023-29) (also referred to after this as the MCAI), to 
correct an unsafe condition on all Bombardier, Inc., Model BD-100-1A10 
airplanes. The MCAI states the time limits/maintenance check (TLMC) 
airworthiness limitation (AWL) Task 54-51-00-111*, ``Discard of the Aft 
Engine Mount Bolts, Part No. MS21250-07, Non-Serialized,'' was not 
performed on some Challenger 300 in-service airplanes due to a 
misleading part number (P/N) referenced in the TLMC manual. The task 
requires the discard and replacement of the aft engine mount attachment 
bolt, P/N MS21250-07, while the P/N shown in the TLMC manual is P/N 
MS21250-7 in lieu of P/N MS21250-07. Bombardier revised the TLMC AWL 
task and the relevant sections in the aircraft maintenance manual and 
the aircraft illustrated parts catalog with P/N MS21250-07 to ensure 
timely discard and replacement of the aft engine mount attachment 
bolts.

[[Page 48140]]

    Airplanes having serial numbers 20913 and subsequent must comply 
with the airworthiness limitations specified as part of the approved 
type design and referenced on the type certificate data sheet; this 
proposed AD therefore does not include those airplanes in the 
applicability.
    The FAA is proposing this AD to address potential failures of the 
aft engine mount attachment bolt, P/N MS21250-07. The unsafe condition, 
if not addressed, could lead to the detachment of the engine from the 
airplane, which could contribute to a catastrophic failure.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2024-1479.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed the following documents. This service information 
specifies a revised airworthiness limitation for the replacement of the 
aft engine mount attachment bolts, P/N MS21250-07. These documents are 
distinct since they apply to different airplane configurations. The 
asterisk (or ``one star'') with the last three digits of the task 
numbers indicates that the task is an airworthiness limitation task.
     Section 5-10-10, ``Life Limits (Structures),'' of part 2, 
``Airworthiness Limitations,'' of the Bombardier Challenger 300 Time 
Limits/Maintenance Check, CH 300, Revision 24, dated August 9, 2023, 
which include Task 54-51-00-111*, ``Discard of the Aft Engine Mount 
Bolts, Part No. MS21250-07, Non-Serialized.''
     Section 5-10-10, ``Life Limits (Structures)'' of part 2, 
``Airworthiness Limitations,'' of the Bombardier Challenger 350 Time 
Limits/Maintenance Check, CH 350, Revision 14, dated August 9, 2023, 
which include Task 54-51-00-111*, ``Discard of the Aft Engine Mount 
Bolts, Part No. MS21250-07, Non-Serialized.''
    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 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 accomplishing revising the existing 
maintenance or inspection program, as applicable, to incorporate a 
revised airworthiness limitation.
    This proposed AD would require revisions to certain operator 
maintenance documents to include new actions (e.g., inspections). 
Compliance with these actions is required by 14 CFR 91.403(c). For 
airplanes that have been previously modified, altered, or repaired in 
the areas addressed by this proposed AD, the operator may not be able 
to accomplish the actions described in the revisions. In this 
situation, to comply with 14 CFR 91.403(c), the operator must request 
approval for an alternative method of compliance according to paragraph 
(i)(1) of this proposed AD.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 731 airplanes of U.S. registry. The FAA estimates the following 
costs to comply with this proposed AD:
    The FAA has determined that revising the maintenance or inspection 
program takes an average of 90 work-hours per operator, although the 
agency recognizes that this number may vary from operator to operator. 
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 
agency estimates the average total cost per operator to be $7,650 (90 
work-hours x $85 per work-hour).

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:

Bombardier Inc.: Docket No. FAA-2024-1479; Project Identifier MCAI-
2023-00657-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by July 22, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Bombardier, Inc., Model BD-100-1A10 
airplanes, certificated in any category, having serial numbers (S/
Ns) 20002 through 20912 inclusive.

(d) Subject

    Air Transport Association (ATA) of America Code America Code 54, 
Nacelles/Pylons.

[[Page 48141]]

(e) Unsafe Condition

    This AD was prompted by a determination that new or more 
restrictive airworthiness limitations are necessary. The FAA is 
issuing this AD to address potential failures of the aft engine 
mount attachment bolt, part number MS21250-07. The unsafe condition, 
if not addressed, could lead to the detachment of the engine from 
the airplane, which could contribute to a catastrophic failure.

(f) Compliance

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

(g) Maintenance or Inspection Program Revision

    Within 60 days after the effective date of this AD, revise the 
existing maintenance or inspection program, as applicable, to 
incorporate the information specified in paragraphs (g)(1) and (2) 
of this AD, as applicable. The initial compliance time for doing the 
tasks is at the time specified in the applicable time limit/
maintenance check (TLMC) document specified in paragraphs (g)(1) and 
(2) of this AD, or within 60 days after the effective date of this 
AD, whichever occurs later.
    (1) For airplane S/Ns 20002 through 20500 inclusive: Task 54-51-
00-111*, ``Discard of the Aft Engine Mount Bolts, Part No. MS21250-
07, Non-Serialized'' of TLMC Section 5-10-10, Part 2, Airworthiness 
Limitations,'' of the Bombardier Challenger 300 Time Limits/
Maintenance Check, CH 300, Revision 24, dated August 9, 2023.
    (2) For airplane S/Ns 20501 through 20912 inclusive: Task 54-51-
00-111*, ``Discard of the Aft Engine Mount Bolts, Part No. MS21250-
07, Non-Serialized'' of TLMC Section 5-10-10, Part 2, Airworthiness 
Limitations,'' of the Bombardier Challenger 350 Time Limits/
Maintenance Check, CH 350, Revision 14, dated August 9, 2023.
    Note 1 to paragraph (g): The asterisk (or ``one star'') with the 
last three digits of the task numbers listed in (g)(1) and (2) of 
this AD indicates that the task is an airworthiness limitation task.

(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., inspections) or intervals may be used unless the 
actions or intervals, are approved as an alternative method of 
compliance (AMOC) in accordance with the procedures specified in 
paragraph (i)(1) of this AD.

(i) Other FAA 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 the address identified 
in paragraph (j) of this AD. Information may be emailed to: 9-AVS-
[email protected]. 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.

(j) Additional Information

    For more information about this AD, contact Yaser Osman, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; telephone 516-228-7300; email [email protected].

(k) 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) Section 5-10-10, ``Life Limits (Structures),'' of Part 2, 
``Airworthiness Limitations,'' of the Bombardier Challenger 300 Time 
Limits/Maintenance Check, CH 300, Revision 24, dated August 9, 2023.
    (ii) Section 5-10-10, ``Life Limits (Structures),'' of Part 2, 
``Airworthiness Limitations,'' of the Bombardier Time Limits/
Maintenance Check, CH 350, Revision 14, dated August 9, 2023.
    (3) For service information identified in this AD, contact 
Bombardier Business Aircraft Customer Response Center, 400 
C[ocirc]te-Vertu Road West, Dorval, Qu[eacute]bec H4S 1Y9, Canada; 
telephone 514-855-2999; email bombardier.com">ac.yul@aero.bombardier.com; website 
bombardier.com.
    (4) You may view this material 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 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 May 28, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2024-12045 Filed 6-4-24; 8:45 am]
BILLING CODE 4910-13-P