[Federal Register Volume 83, Number 106 (Friday, June 1, 2018)]
[Rules and Regulations]
[Pages 25361-25363]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-11455]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2018-0471; Special Conditions No. 25-728-SC]


Special Conditions: Textron Aviation Inc. Model 700 Series 
Airplanes; Installed Rechargeable Lithium Batteries

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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

SUMMARY: These special conditions are issued for the Textron Aviation 
Inc. (Textron) Model 700 series 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 the installation of 
rechargeable lithium 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 Textron Aviation Inc. on June 1, 
2018. Send comments on or before July 16, 2018.

ADDRESSES: Send comments identified by Docket No. FAA-2018-0471 using 
any of the following methods:
     Federal eRegulations Portal: Go to http://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: The FAA will post all comments it receives, without 
change, to http://www.regulations.gov/, including any personal 
information the commenter provides. Using the search function of the 
docket website, anyone can find and read the electronic form of all 
comments received into any FAA docket, including the name of the 
individual sending the comment (or signing the comment for an 
association, business, labor union, etc.). DOT's complete Privacy Act 
Statement can be found in the Federal Register published on April 11, 
2000 (65 FR 19477-19478).
    Docket: Background documents or comments received may be read at 
http://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, Airplane and Flight 
Crew Interface Section, AIR-671, Transport Standards 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 
previously has been published in the Federal Register for public 
comment. These special conditions have been derived without substantive 
change from those previously issued. It is unlikely that prior public 
comment would result in a significant change from the substance 
contained herein. Therefore, the FAA has determined that

[[Page 25362]]

prior public notice and comment are unnecessary, and finds that, for 
the same reason, good cause exists for adopting these special 
conditions upon publication in the Federal Register.

Comments Invited

    We invite 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.
    We will consider all comments we receive by the closing date for 
comments. We may change these special conditions based on the comments 
we receive.

Background

    On November 20, 2014, Textron applied for a type certificate for 
their new Model 700 series airplanes. The Textron Model 700 series 
airplanes are transport-category, twin turbofan-powered airplanes with 
standard seating provisions for up to 12 passengers and 2 crewmembers, 
and a maximum takeoff weight of 38,514 lbs.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.17, Textron must show that the Model 700 series airplanes meet 
the applicable provisions of part 25 as amended by amendments 25-1 
through 25-139, 25-141, and 25-143.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the Textron Model 700 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 type certificate for that model be amended 
later to include any other model that incorporates 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 700 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 the type 
certification basis under Sec.  21.17(a)(2).

Novel or Unusual Design Features

    The Textron Model 700 series airplanes will incorporate the 
following novel or unusual design features:
    The installation of rechargeable lithium batteries. Known uses of 
rechargeable and non-rechargeable lithium batteries on airplanes 
include:
     Flightdeck and avionics systems such as displays, global 
positioning systems, cockpit voice recorders, flight data recorders, 
underwater-locator-beacons, navigation computers, integrated avionics 
computers, satellite network/communication systems, communication 
management units, and remote monitor electronic line replaceable units;
     Cabin safety, entertainment and communications equipment 
including emergency locator transmitters, life rafts, escape slides, 
seat belt air bags, cabin management systems, Ethernet switches, 
routers and media servers, wireless systems, internet/in-flight 
entertainment systems, satellite televisions, remotes and handsets; and
     Systems in cargo areas including door controls, sensors, 
video surveillance equipment and security systems.

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, and the FAA 
does not provide further explanation for them at this time.
    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 will apply to all rechargeable lithium 
battery installations in lieu of Sec.  25.1353(b)(1) through (b)(4) at 
Amendment 25-123. Section 25.1353(b)(1) through (b)(4) at Amendment 25-
123 will 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 700 series airplane. Should

[[Page 25363]]

Textron 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 a certain novel or unusual design feature 
on one model series of 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, 
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 Inc. Model 700 series 
airplane:
    In lieu of Sec.  25.1353(b)(1) through (b)(4) at Amendment 25-123, 
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 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.

    Issued in Des Moines, Washington, on May 23, 2018.
Victor Wicklund,
Manager, Transport Standards Branch, Policy and Innovation Division, 
Aircraft Certification Service.
[FR Doc. 2018-11455 Filed 5-31-18; 8:45 am]
 BILLING CODE 4910-13-P


