[Federal Register Volume 90, Number 96 (Tuesday, May 20, 2025)]
[Proposed Rules]
[Pages 21437-21439]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-08934]


========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

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. 90, No. 96 / Tuesday, May 20, 2025 / Proposed 
Rules

[[Page 21437]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-0908; Project Identifier MCAI-2025-00035-T]
RIN 2120-AA64


Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Bombardier, Inc., Model BD-700-1A10 airplanes. This 
proposed AD was prompted by a report indicating that the clearance 
between therapeutic flexible oxygen hoses and electrical harnesses may 
be non-compliant to design requirements, and that positive separation 
mechanisms and appropriate protective barriers may not have been 
installed in accordance with the applicable installation standards. 
This proposed AD would require a detailed inspection of the therapeutic 
flexible oxygen hose for damage and protection, and the electrical 
harnesses for damage; a detailed inspection for the clearance between 
the therapeutic oxygen rigid tube to oxygen hose elbow fitting (also 
referred to as elbow fitting), if applicable, and the nearest 
electrical harness, and between the therapeutic flexible oxygen hose 
and electrical harness; and applicable related investigative and 
corrective actions. 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 7, 
2025.

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-2025-0908; 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 Bombardier material identified in this proposed 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.
     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.

FOR FURTHER INFORMATION CONTACT: Brenda L. Buitrago, Aviation Safety 
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
phone: 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 the ADDRESSES section. Include ``Docket No. FAA-2025-0908; 
Project Identifier MCAI-2025-00035-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 
contact Brenda L. Buitrago, Aviation Safety Engineer, FAA, 1600 Stewart 
Avenue, Suite 410, Westbury, NY 11590; phone: 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-2025-02, dated January 14, 2025 
(Transport Canada AD CF-2025-02) (also referred to as the MCAI), to 
correct an unsafe condition on certain Bombardier, Inc., Model BD-700-
1A10 airplanes. The MCAI states that Bombardier, Inc., has discovered 
that the clearance between therapeutic flexible oxygen hoses and 
electrical harnesses may be non-compliant to design requirements, and 
that the positive separation mechanisms and appropriate protective 
barriers may not have been installed in accordance with the applicable 
installation standards. The MCAI also states that instances of hard 
fouling have been observed on the production line, which

[[Page 21438]]

could lead to damage to the electrical harness and subsequent latent 
failure of the firewall hydraulic shutoff valve. This condition could 
result in the inability to control a powerplant fire in the presence of 
a hydraulic fluid leak.
    The FAA is proposing this AD to address the unsafe condition on 
these products.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2025-0908.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed Bombardier Service Bulletin 700-35-016, Bombardier 
Service Bulletin 700-35-6006, and Bombardier Service Bulletin 700-35-
6503, all dated June 12, 2024. This material specifies procedures for 
accomplishing the following actions near fuselage station (FS) 530 
right-hand side (RHS) and FS 650.00 RHS and applicable related 
investigative and corrective actions, including:
     A detailed inspection to determine the gap between the 
clocking angle of the therapeutic oxygen rigid tube to oxygen hose 
elbow fitting, if equipped, and the nearest electrical harness.
     A detailed inspection for damage (i.e., crushing, fraying, 
or permanent deformation) to the therapeutic flexible oxygen hose, part 
number (P/N) 38911-5-0250, and to determine if protection (i.e., split 
convolex shroud, P/N HCTE0437-0-SP or similar, or spiral wrap, P/N TSW 
\1/4\ or similar) is installed on the therapeutic flexible oxygen hose.
     A detailed inspection of the electrical harnesses 
surrounding the therapeutic flexible oxygen hose for damage (i.e., 
damaged wire sheathing or cut or nicked wires).
    The applicable corrective actions include the following:
     If the gap between the clocking angle of the therapeutic 
oxygen rigid tube to oxygen hose elbow fitting and nearest harness is 
less than 0.5 inches, adjusting the elbow fitting to ensure the maximum 
possible clearance between the fitting and nearest harness.
     If the clearance between the wiring harness and oxygen 
hose is less than 0.5 inches, installing a Teflon cable wrap or Nomex 
sleeving on the wiring harness.
     Replacing any damaged therapeutic flexible oxygen hose 
with a new hose.
     Installing a split convolex shroud (P/N HCTE0437-0-SP) on 
the therapeutic flexible oxygen hose, if the protection is missing.
     Repairing any damaged electrical harnesses surrounding the 
therapeutic flexible oxygen hose.
    The related investigative actions are leak and operational tests of 
the therapeutic oxygen system if any parts are repaired or replaced.
    These documents are distinct since they apply to different airplane 
configurations.
    This material 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 
material 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 the actions specified 
in the material already described. See ``Differences Between This 
Proposed AD and the Referenced Material'' for a discussion of the 
general differences included in this AD.

Differences Between This Proposed AD and the Referenced Material

    Steps 2.B.(7) and (14) of Bombardier Service Bulletin 700-35-016, 
Bombardier Service Bulletin 700-35-6006, and Bombardier Service 
Bulletin 700-35-6503, all dated June 12, 2024, specify a corrective 
action to install a Teflon cable wrap or Nomex sleeving on the 
electrical wiring harness if the clearance between the electrical 
wiring harness and therapeutic flexible oxygen hose is less than 0.5 
inches. This proposed AD clarifies that prior to that corrective 
action, a detailed inspection to determine the clearance between the 
electrical wiring harnesses and therapeutic flexible oxygen hose must 
be performed.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 317 airplanes of U.S. registry. The FAA estimates the following 
costs to comply with this proposed AD:

                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
                     Labor cost                       Parts cost     Cost per product    Cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
10 work-hours x $85 per hour = $850................           $0                 $850                  $269,450
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition 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:

[[Page 21439]]

    (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-2025-0908; Project Identifier MCAI-
2025-00035-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by July 7, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Bombardier, Inc., Model BD-700-1A10 
airplanes, certificated in any category, as identified in Bombardier 
Service Bulletin 700-35-016, dated June 12, 2024; Bombardier Service 
Bulletin 700-35-6006, dated June 12, 2024; and Bombardier Service 
Bulletin 700-35-6503, dated June 12, 2024.

(d) Subject

    Air Transport Association (ATA) of America Code 35, Oxygen.

(e) Unsafe Condition

    This proposed AD was prompted by a report indicating that the 
clearance between therapeutic flexible oxygen hoses and electrical 
harnesses may be non-compliant to design requirements, and that 
positive separation mechanisms and appropriate protective barriers 
may not have been installed in accordance with the applicable 
installation standards. The FAA is proposing this AD to prevent 
damage to the electrical harness for the therapeutic flexible oxygen 
hose and subsequent latent failure of the firewall hydraulic shutoff 
valve. The unsafe condition, if not addressed, could result in the 
inability to control a powerplant fire in the presence of a 
hydraulic fluid leak.

(f) Compliance

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

(g) Detailed Inspections and Related Investigative and Corrective 
Actions

    Within 10 years after the effective date of this AD, do all the 
actions specified in paragraphs (g)(1) through (4) of this AD, and 
do all the applicable related investigative and corrective actions 
before further flight, in accordance with sections 2.B and 2.C of 
the Accomplishment Instructions of Bombardier Service Bulletin 700-
35-016, Bombardier Service Bulletin 700-35-6006, and Bombardier 
Service Bulletin 700-35-6503, all dated June 12, 2024, as 
applicable.
    (1) Do a detailed inspection to determine the gap between the 
clocking angle of the therapeutic oxygen rigid tube to oxygen hose 
elbow fitting, if equipped, and the nearest electrical harness.
    (2) Do a detailed inspection of the therapeutic flexible oxygen 
hose, P/N 38911-5-0250, for damage and to determine if protection is 
installed on the hose.
    (3) Do a detailed inspection of the electrical harnesses 
surrounding the therapeutic flexible oxygen hose for damage.
    (4) Do a detailed inspection to determine the clearance between 
the electrical harnesses and therapeutic flexible oxygen hose.

(h) 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, send it to the attention of the 
person identified in paragraph (i) of this AD and email to: 
[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.

(i) Additional Information

    For more information about this AD, contact Brenda L. Buitrago, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; phone: 516-228-7300; email: [email protected].

(j) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference of the material listed in this paragraph 
under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this material as applicable to do the actions 
required by this AD, unless this AD specifies otherwise.
    (i) Bombardier Service Bulletin 700-35-016, dated June 12, 2024.
    (ii) Bombardier Service Bulletin 700-35-6006, dated June 12, 
2024.
    (iii) Bombardier Service Bulletin 700-35-6503, dated June 12, 
2024.
    (3) For Bombardier material 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 13, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2025-08934 Filed 5-19-25; 8:45 am]
BILLING CODE 4910-13-P