[Federal Register Volume 88, Number 110 (Thursday, June 8, 2023)]
[Rules and Regulations]
[Pages 37467-37469]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-12278]



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 Rules and Regulations
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 This section of the FEDERAL REGISTER contains regulatory documents 
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  Federal Register / Vol. 88 , No. 110 / Thursday, June 8, 2023 / Rules 
and Regulations  

[[Page 37467]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2023-0841; Special Conditions No. 25-837-SC]


Special Conditions: Airbus SAS Model A320 and A321 Series 
Airplanes; Rechargeable Lithium Batteries and Battery System 
Installations

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Airbus SAS 
(Airbus) Model A320-251N, -252N, -253N, -271N, -272N, and -273N; and 
Model A321-251NX, -252NX, -253NX, -271NX, and -272NX airplanes. These 
airplanes will have a novel or unusual design feature when compared to 
the state of technology envisioned in the airworthiness standards for 
transport-category airplanes. This design feature is a mini emergency 
power supply unit containing rechargeable lithium-ion batteries. The 
applicable airworthiness regulations do not contain adequate or 
appropriate safety standards for this design feature. These special 
conditions contain the additional safety standards that the 
Administrator considers necessary to establish a level of safety 
equivalent to that established by the existing airworthiness standards.

DATES: This action is effective on Airbus on June 8, 2023. Send 
comments on or before July 24, 2023.

ADDRESSES: Send comments identified by Docket No. FAA-2023-0841 using 
any of the following methods:
     Federal eRegulations Portal: Go to https://www.regulations.gov/ and follow the online instructions for sending 
your comments electronically.
     Mail: Send comments to Docket Operations, M-30, U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE, Room 
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue SE, Washington, DC between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
     Privacy: Except for Confidential Business Information as 
described in the following paragraph, and other information as 
described in title 14, Code of Federal Regulations (14 CFR) 11.35, the 
FAA will post all comments received without change to https://www.regulations.gov/, including any personal information you provide. 
The FAA will also post a report summarizing each substantive verbal 
contact received about these special conditions.
     Confidential Business Information: 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 these special 
conditions contain commercial or financial information that is 
customarily treated as private, that you actually treat as private, and 
that is relevant or responsive to these special conditions, 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 the indicated comments will not be placed in the public 
docket of these special conditions. Send submissions containing CBI to 
the individual listed in the FOR FURTHER INFORMATION CONTACT section. 
Comments the FAA receives, which are not specifically designated as 
CBI, will be placed in the public docket for these special conditions.
    Docket: Background documents or comments received may be read at 
https://www.regulations.gov/ at any time. Follow the online 
instructions for accessing the docket or go to Docket Operations in 
Room W12-140 of the West Building Ground Floor at 1200 New Jersey 
Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday through 
Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Nazih Khaouly, Aircraft Systems, AIR-
623, Technical Innovation Policy Branch, Policy and Innovation 
Division, Aircraft Certification Service, Federal Aviation 
Administration, 2200 South 216th Street, Des Moines, Washington 98198; 
telephone (206) 231-3160; email [email protected].

SUPPLEMENTARY INFORMATION: The substance of these special conditions 
has been published in the Federal Register for public comment in 
several prior instances with no substantive comments received. 
Therefore, the FAA finds, pursuant to 14 CFR 11.38(b), that new 
comments are unlikely, and notice and comment prior to this publication 
are unnecessary.

Comments Invited

    The FAA invites interested people to take part in this rulemaking 
by sending written comments, data, or views. The most helpful comments 
reference a specific portion of the special conditions, explain the 
reason for any recommended change, and include supporting data.
    The FAA will consider all comments received by the closing date for 
comments, and will consider comments filed late if it is possible to do 
so without incurring delay. The FAA may change these special conditions 
based on the comments received.

Background

    On August 17, 2022, Airbus SAS applied for a change to Type 
Certificate No. A28NM to install a mini emergency power supply unit 
containing rechargeable, lithium-ion batteries and battery system on 
Airbus A320-251N, -252N, -253N, -271N, -272N, and -273N and Airbus 
Model A321-251NX, -252NX, -253NX, -271NX, and -272NX airplanes.
    These airplanes, approved under Type Certificate No. A28NM, are 
twin-engine transport category airplanes with a maximum seating of 
capacity between 179 to 244 passengers and a maximum takeoff weight 
between 154,322 to 213,848 pounds, depending on model.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101,

[[Page 37468]]

Airbus must show that changes to the Airbus Model A320-251N, -252N, -
253N, -271N, -272N, and -273N and Airbus Model A321-251NX, -252NX, -
253NX, -271NX, and -272NX airplanes, as changed, continues to meet the 
applicable provisions of the regulations listed in Type Certificate No. 
A28NM or the applicable regulations in effect on the date of 
application for the change, except for earlier amendments as agreed 
upon by the FAA.
    If the Administrator finds that the applicable airworthiness 
regulations (e.g., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the Airbus Model A320-251N, -252N, -
253N, -271N, -272N, and -273N, and Airbus Model A321-251NX, -252NX, -
253NX, -271NX, and -272NX airplanes because of a novel or unusual 
design feature, special conditions are prescribed under the provisions 
of Sec.  21.16.
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate for that model be amended 
later to include any other model that incorporates the same novel or 
unusual design feature, or should any other model already included on 
the same type certificate be modified to incorporate the same novel or 
unusual design feature, these special conditions would also apply to 
the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the Airbus Model A320-251N, -252N, -253N, -271N, -272N, and 
-273N, and Airbus Model A321-251NX, -252NX, -253NX, -271NX, and -272NX 
airplanes must comply with the fuel-vent and exhaust-emission 
requirements of 14 CFR part 34, and the noise-certification 
requirements of 14 CFR part 36.
    The FAA issues special conditions, as defined in 14 CFR 11.19, in 
accordance with Sec.  11.38, and they become part of the type 
certification basis under Sec.  21.101.

Novel or Unusual Design Features

    The Airbus Model A320-251N, -252N, -253N, -271N, -272N, and -273N; 
and Model A321-251NX, -252NX, -253NX, -271NX, and -272NX airplanes will 
incorporate the following novel or unusual design feature Mini 
Emergency Power Supply Unit containing rechargeable lithium-ion 
batteries.

Discussion

    Rechargeable lithium batteries and battery systems are considered 
to be a novel or unusual design feature in transport category 
airplanes, with respect to the requirements in Sec.  25.1353. This type 
of battery has certain failure, operational, and maintenance 
characteristics that differ significantly from those of the nickel-
cadmium and lead-acid rechargeable batteries currently approved for 
installation on transport category airplanes. These batteries and 
battery systems introduce higher energy levels into airplane systems 
through new chemical compositions in various battery-cell sizes and 
construction. Interconnection of these cells in battery packs 
introduces failure modes that require unique design considerations, 
such as provisions for thermal management.
    Special Condition 1 requires that each individual cell within a 
battery and battery system be designed to maintain safe temperatures 
and pressures. Special Condition 2 addresses these same issues but for 
the entire battery system.
    Special Condition 2 requires that the batteries and battery system 
be designed to prevent propagation of a thermal event, such as self-
sustained, uncontrolled increases in temperature or pressure from one 
cell to adjacent cells.
    Special Conditions 1 and 2 are intended to ensure that the cells 
and battery system are designed to eliminate the potential for 
uncontrollable failures. However, a certain number of failures will 
occur due to various factors beyond the control of the designer. 
Therefore, other special conditions are intended to protect the 
airplane and its occupants if failure occurs.
    Special Conditions 3, 7, and 8 are self-explanatory.
    Special Condition 4 clarifies that the flammable-fluid fire-
protection requirements of Sec.  25.863 apply to rechargeable lithium 
battery installations. Section 25.863 is applicable to areas of the 
airplane that could be exposed to flammable fluid leakage from airplane 
systems. Rechargeable lithium batteries contain electrolyte that is a 
flammable fluid.
    Special Condition 5 requires each rechargeable lithium battery and 
battery system installation to not damage surrounding structure or 
adjacent systems, equipment, or electrical wiring from corrosive fluids 
or gases that may escape in such a way as to cause a major or more 
severe failure condition.
    Special Condition 6 requires each rechargeable lithium battery and 
battery system installation to have provisions to prevent any hazardous 
effect on airplane structure or systems caused by the maximum amount of 
heat it can generate due to any failure of it or its individual cells. 
The means of meeting special conditions 5 and 6 may be the same, but 
they are independent requirements addressing different hazards. Special 
Condition 5 addresses corrosive fluids and gases, whereas special 
condition 6 addresses heat.
    Special Condition 9 requires rechargeable lithium batteries and 
battery systems to have ``automatic'' means, for charge rate and 
disconnect, due to the fast acting nature of lithium battery chemical 
reactions. Manual intervention would not be timely or effective in 
mitigating the hazards associated with these batteries.
    These special conditions apply to all rechargeable lithium 
batteries and battery system installations in lieu of Sec.  
25.1353(b)(1) through (4) at amendment 25-123, or Sec.  25.1353(c)(1) 
through (4) at earlier amendments. Those regulations will remain in 
effect for other battery installations on these airplanes.
    These special conditions contain the additional safety standards 
that the Administrator considers necessary to establish a level of 
safety equivalent to that established by the existing airworthiness 
standards.

Applicability

    As discussed above, these special conditions are applicable to the 
Airbus Model A320-251N, -252N, -253N, -271N, -272N, and -273N; and 
Model A321-251NX, -252NX, -253NX, -271NX, and -272NX airplanes. Should 
Airbus apply at a later date for a change to the type certificate to 
include another model incorporating the same novel or unusual design 
feature, these special conditions would apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on Airbus Model A320-251N, -252N, -253N, -271N, -272N, and -273N; and 
Model A321-251NX, -252NX, -253NX, -271NX, and -272NX airplanes. It is 
not a rule of general applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

Authority Citation

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702, and 
44704.

The Special Conditions

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type

[[Page 37469]]

certification basis for Airbus Model A320-251N, -252N, -253N, -271N, -
272N and -273N; and Model A321-251NX, -252NX, -253NX, -271NX and -272NX 
airplanes.

Rechargeable Lithium Battery and Battery System Installations

    In lieu of Sec.  25.1353(b)(1) through (4) at amendment 25-123, or 
Sec.  25.1353(c)(1) through (4) at earlier amendments, each 
rechargeable lithium battery installation must:
    1. Be designed to maintain safe cell temperatures and pressures 
under all foreseeable operating conditions to prevent fire and 
explosion.
    2. Be designed to prevent the occurrence of self-sustaining, 
uncontrollable increases in temperature or pressure, and automatically 
control the charge rate of each cell to protect against adverse 
operating conditions, such as cell imbalance, back charging, 
overcharging, and overheating.
    3. Not emit explosive or toxic gases, either in normal operation or 
as a result of its failure that may accumulate in hazardous quantities 
within the airplane.
    4. Meet the requirements of Sec.  25.863.
    5. Not damage surrounding structure or adjacent systems, equipment, 
or electrical wiring from corrosive fluids or gases that may escape in 
such a way as to cause a major or more- severe failure condition.
    6. Have provisions to prevent any hazardous effect on airplane 
structure or systems caused by the maximum amount of heat it can 
generate due to any failure of it or its individual cells.
    7. Have a failure sensing and warning system to alert the 
flightcrew if its failure affects safe operation of the airplane.
    8. Have a monitoring and warning feature that alerts the flightcrew 
when its charge state falls below acceptable levels if its function is 
required for safe operation of the airplane.
    9. Have a means to automatically disconnect from its charging 
source in the event of an over-temperature condition, cell failure or 
battery failure.

    Note:  A battery system consists of the battery, battery charger 
and any protective, monitoring and alerting circuitry or hardware 
inside or outside of the battery. It also includes vents (where 
necessary) and packaging. For the purpose of these special 
conditions, a battery and the battery system is referred to as a 
battery.


    Issued in Des Moines, Washington, on June 4, 2023.
Suzanne A. Masterson,
Acting Manager, Technical Policy Branch, Policy and Standards Division, 
Aircraft Certification Service.
[FR Doc. 2023-12278 Filed 6-7-23; 8:45 am]
BILLING CODE 4910-13-P