[Federal Register Volume 87, Number 66 (Wednesday, April 6, 2022)]
[Rules and Regulations]
[Pages 19789-19791]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-07255]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2022-0277; Special Conditions No. 25-814-SC]


Special Conditions: Peregrine, Textron Aviation Model 400A 
Airplane; Rechargeable Lithium Batteries

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 Textron Aviation 
(Textron) Model 400A airplane. This airplane, as modified by Peregrine, 
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 main ship rechargeable 
lithum battery. 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 Peregrine on April 6, 2022. Send 
comments on or before May 23, 2022.

ADDRESSES: Send comments identified by Docket No. FAA-2022-0277 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 (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. Submissions containing CBI should 
be sent to 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 and fax 206-231-
3160; email [email protected]. 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 and fax 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 Sec.  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. The FAA may change these special conditions based on the 
comments received.

Background

    On November 30, 2021, Peregrine applied for a supplemental type 
certificate for the installation of a True Blue Power TB40 main ship 
rechargeable lithium battery in the Model 400A airplane. The Textron 
Model 400A airplane is a twin-engine transport category business jet, 
with a maxium passenger capacity of 11, and

[[Page 19790]]

has a maximum takeoff weight of 16,300 pounds.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101, Peregrine must show that the Model 400A airplane, as 
changed, continues to meet the applicable provisions of the regulations 
listed in Type Certificate No. A16SW 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 Peregrine Model 400A airplane 
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 Textron Model 400A airplane 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 Textron Model 400A airplane will incorporate the following 
novel or unusual design features:
    Installation of True Blue Power TB40 main ship rechargeable lithium 
battery.

Discussion

    Rechargeable lithium batteries 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 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 be designed to maintain safe temperatures and pressures. 
Special Condition 2 addresses these same issues but for the entire 
battery. Special Condition 2 requires that the battery 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 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 
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 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 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 battery 
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 remain in effect for other battery installations.
    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 
Textron Model 400A airplane. Should Peregrine apply at a later date for 
a supplemental type certificate to modify any other model included on 
Type Certificate No. A16SW to incorporate the same novel or unusual 
design feature, these special conditions would apply to that model as 
well.

Conclusion

    This action affects only a certain novel or unusual design feature 
on one model of airplane. It is not a rule of general applicability and 
affects only the applicant who applied to the FAA for approval of this 
feature 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 Special Conditions

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for Textron Aviation Model 400A airplanes, 
as modified by Peregrine.
    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

[[Page 19791]]

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 flight 
crew 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 Kansas City, Missouri, on April 1, 2022.
Patrick R. Mullen,
Manager, Technical Innovation Policy Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2022-07255 Filed 4-5-22; 8:45 am]
BILLING CODE 4910-13-P


