[Federal Register Volume 90, Number 155 (Thursday, August 14, 2025)]
[Rules and Regulations]
[Pages 39109-39112]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-15481]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-0908; Project Identifier MCAI-2025-00035-T; 
Amendment 39-23105; AD 2025-16-07]
RIN 2120-AA64


Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Bombardier, Inc., Model BD-700-1A10 airplanes. This 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 AD requires 
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 
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective September 18, 2025.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of September 18, 
2025.

ADDRESSES: 
    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 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 Bombardier material identified in this AD, contact 
Bombardier Business

[[Page 39110]]

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. It is also available at regulations.gov under 
Docket No. FAA-2025-0908.

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:

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 Bombardier, 
Inc., Model BD-700-1A10 airplanes. The NPRM was published in the 
Federal Register on May 20, 2025 (90 FR 21437). The NPRM was prompted 
by AD CF-2025-02, dated January 14, 2025, issued by Transport Canada, 
which is the aviation authority for Canada (Transport Canada AD CF-
2025-02) (also referred to as the MCAI). The MCAI states that 
Bombardier, Inc., has discovered the clearance between therapeutic 
flexible oxygen hoses and electrical harnesses may be noncompliant 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 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.
    In the NPRM, the FAA proposed to 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 issuing 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.

Discussion of Final Airworthiness Directive

Comments

    The FAA received no comments on the NPRM or on the determination of 
the cost to the public.

Conclusion

    These products have been approved by the civil aviation authority 
of another country and are approved for operation in the United States. 
Pursuant to the FAA's bilateral agreement with this State of Design 
Authority, that authority has notified the FAA of the unsafe condition 
described in the MCAI referenced above. The FAA reviewed the relevant 
data, considered any 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 these products. 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.

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 inch, adjust 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 inch, install 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.

Costs of Compliance

    The FAA estimates that this AD affects 317 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
----------------------------------------------------------------------------------------------------------------
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 AD.
    The FAA has included all known costs in its cost estimate. 
According to

[[Page 39111]]

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:

2025-16-07 Bombardier, Inc.: Amendment 39-23105; Docket No. FAA-
2025-0908; Project Identifier MCAI-2025-00035-T.

(a) Effective Date

    This airworthiness directive (AD) is effective September 18, 
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 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 issuing 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, part number (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,

[[Page 39112]]

visit www.archives.gov/federal-register/cfr/ibr-locations or email 
[email protected].

    Issued on August 1, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2025-15481 Filed 8-13-25; 8:45 am]
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