[Federal Register Volume 88, Number 105 (Thursday, June 1, 2023)]
[Proposed Rules]
[Pages 35781-35783]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-11682]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2022-0205; Notice No. 25-22-02-SC]


Special Conditions: Lufthansa Tecknik AG, Airbus Models A319-133 
and A321-200 Series Airplanes; Supercapacitor Systems and Installation

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This action proposes special conditions for the Airbus Model 
A319-133 and A321-200 series airplanes. This airplane, as modified by 
Lufthansa Tecknik AG (Lufthansa), 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 the installation of an uninterruptible power supply (UPS) 
system based on supercapacitor technology. The current airworthiness 
regulations do not contain adequate or appropriate safety standards for 
this design feature. These proposed 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: Send comments on or before July 17, 2023.

ADDRESSES: Send comments identified by Docket No. FAA-2022-0205 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.
    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: Daniel Poblete, Electrical Systems, 
AIR-626A, Technical Policy Branch, Policy and Innovation Division, 
Aircraft Certification Service, Federal Aviation Administration, 3960 
Paramount Blvd., Suite 100, Lakewood, CA 90712-4137; telephone and fax 
(562) 627-5335; email [email protected].

SUPPLEMENTARY INFORMATION: 

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 proposed 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.

Privacy

    Except for Confidential Business Information (CBI) 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 above. Comments the FAA receives, which are 
not specifically designated as CBI, will be placed in the public docket 
for these special conditions.

Background

    On February 17, 2021, Lufthansa applied for a supplemental type 
certificate for the installation of a UPS system in the Model A319-133 
and A321-200 series airplanes. The Airbus Model A319-133 and A321-200 
series airplanes are twin-engine, transport category airplanes. The 
Airbus Model A319-133 airplane has a maximum passenger seating capacity 
of 160, and a maximum takeoff weight of 154,322 pounds. The Airbus 
Model A321-200 airplane has a maximum passenger seating capacity 230, 
and a maximum takeoff weight of 213,848 pounds.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101, Lufthansa must show that the Model A319-133 and A321-200 
series airplanes, as changed, continue 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 A319-133 and A321-200 
series 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 applicant apply for a supplemental type 
certificate to modify any other model included on the same type 
certificate 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 A319-133 and A321-200 series 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

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the type certification basis under Sec.  21.101.

Novel or Unusual Design Features

    The Airbus Model A319-133 and A321-200 series airplanes will 
incorporate the following novel or unusual design features:
    This design feature for this installation of a UPS system is based 
on supercapacitor technology.

Discussion

    Currently, there are no regulatory or industry standards for 
supercapacitors and their installation on transport category airplanes. 
Supercapacitors are used to provide power to non-essential cabin 
equipment when the normal power source is interrupted for a short 
period of time. In this design, the supercapacitor UPS system will 
allow connected equipment to be provided back-up power if normal 
electrical power source is interrupted and remain operational such as 
during power transfers as well as provide transient voltage surge 
suppression should harmful high voltage transients occur. The UPS is 
only used for systems not critical to continued safe flight and 
landing.
    Since the supercapacitor is being used as a high capacity 
electrical storage device and functions similarly to rechargeable 
batteries, the special conditions used for lithium batteries are 
appropriate for supercapacitor installations and the hazardous 
conditions that could be presented. These special conditions are 
necessary to assist in the testing and installation of this 
supercapacitor on the aircraft.
    Special condition 1 requires that the supercapacitor installation 
be designed to preclude propagation of a thermal event, such as self-
sustained, uncontrolled increases in temperature or pressure. Special 
condition 1 is intended to ensure that the supercapacitor system is 
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 supercapacitor designer. Therefore, other 
special conditions are intended to protect the airplane and its 
occupants if other failures occur.
    Special conditions 2, 6, 8, and 9 are self-explanatory.
    Special condition 3 makes it clear that the flammable fluid fire 
protection requirements of Sec.  25.863 apply to supercapacitor 
installations. Section 25.863 is applicable to areas of the airplane 
that could be exposed to flammable fluid leakage from airplane systems. 
Supercapacitors may contain an electrolyte that is a flammable fluid.
    Special condition 4 requires that each supercapacitor installation 
not damage surrounding structure or adjacent systems, equipment, or 
electrical wiring interconnection system (EWIS) components from 
corrosive fluids or gases that may escape in such a way as to cause a 
hazardous condition.
    While special condition 4 addresses corrosive fluids and gases, 
special condition 5 addresses heat. Special condition 5 requires that 
each supercapacitor installation have provisions to prevent any 
hazardous effect on surrounding structure or adjacent systems, 
equipment or EWIS components, caused by the maximum amount of heat the 
supercapacitor installation can generate due to any failure of the 
supercapacitor installation or any of the individual supercapacitors. 
The means of meeting special conditions 4 and 5 may be the same, but 
the requirements are independent and address different hazards.
    Special condition 7 requires that supercapacitor be disconnected or 
otherwise removed from its charging source without the need for crew 
intervention should the supercapacitor become overheated or fail in a 
manner that may create a safety hazard. This requirement applies to all 
supercapacitor installations and is not limited to those whose proper 
functioning is required for the safe operation of the airplane.
    The proposed 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 A319-133 and A321-200 series airplanes. Should Lufthansa 
apply at a later date for a change to the supplemental type certificate 
to include another model incorporating the same novel or unusual design 
feature included on Type Certificate No. A28NM, these special 
conditions would apply to that model as well.

Conclusion

    This action affects only a certain novel or unusual design feature 
on Airbus Models A319-133 and A321-200 series airplanes. It is not a 
rule of general applicability and affects only the applicant who 
applied to the FAA for approval of these features on the airplane.

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, 44704.

The Proposed Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for Airbus Model A319-133 and A321-200 series airplanes, as modified by 
Lufthansa Technik AG.
    Each supercapacitor installation must:
    1. Be designed to preclude the occurrence of uncontrolled increases 
in temperature or pressure under all foreseeable operating conditions 
to prevent fire and explosion.
    2. Not emit explosive or toxic gasses, in normal operation or as 
the result of its failure that may accumulate in hazardous quantities 
in any area of the airplane.
    3. Meet the requirements of Sec.  25.863.
    4. Not damage surrounding structure or adjacent systems, equipment, 
or electrical wiring interconnection system (EWIS) components from 
corrosive fluids or gases that may escape to cause a hazardous 
condition.
    5. Have provisions to prevent any hazardous effect on surrounding 
structure or adjacent systems, equipment, or EWIS components, caused by 
the maximum amount of heat it can generate during any failure including 
any individual supercapacitors.
    6. Have a means to prevent overheating or overcharging of the 
supercapacitor.
    7. Have a means to automatically disconnect it from its charging 
source in the event of an over-temperature condition or failure.
    8. Have a monitoring and alerting feature that alerts the 
flightcrew when the capacity has fallen below acceptable levels if its 
function is required for safe operation of the airplane. The flightcrew 
alerting must be in accordance with the requirements of Sec.  25.1322.
    9. Have a means to prevent insufficient charging if required for 
safe operation of the airplane.

    Note: A supercapacitor installation consists of the 
supercapacitor(s) and any protective, monitoring and alerting 
circuitry or hardware inside or outside of the Supercapacitor. This 
includes EWIS components as defined by Sec.  25.1701. It also 
includes any venting or cooling system and packaging. For the 
purpose of these special conditions, a

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supercapacitor and the supercapacitor installation is referred to as 
a supercapacitor.


    Issued in Des Moines, Washington, on May 26, 2023.
Suzanne A. Masterson,
Acting Manager, Technical Policy Branch, Policy and Standards Division, 
Aircraft Certification Service.
[FR Doc. 2023-11682 Filed 5-31-23; 8:45 am]
BILLING CODE 4910-13-P