[Federal Register Volume 83, Number 3 (Thursday, January 4, 2018)]
[Rules and Regulations]
[Pages 463-466]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-28454]



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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. 83, No. 3 / Thursday, January 4, 2018 / Rules 
and Regulations  

[[Page 463]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2017-0963; Special Conditions No. 25-707-SC]


Special Conditions: Learjet Inc., Model 45 Airplane; Non-
Rechargeable Lithium Battery Installations

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comment.

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SUMMARY: These special conditions are issued for non-rechargeable 
lithium battery installations on the Learjet Inc. (Learjet) Model 45 
airplane. Non-rechargeable lithium batteries are a novel or unusual 
design feature when compared to the state of technology envisioned in 
the airworthiness standards for transport-category airplanes. 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 Learjet on January 4, 2018. We must 
receive your comments by February 20, 2018.

ADDRESSES: Send comments identified by docket number FAA-2017-0963 
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), as well as at http://DocketsInfo.dot.gov/ gov/.
    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 Branch, AIR-671, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW, Renton, Washington 
98057-3356; telephone 425-227-2432; facsimile 425-227-1149.

SUPPLEMENTARY INFORMATION:

Future Requests for Installation of Non-Rechargeable Lithium Batteries

    The FAA anticipates that non-rechargeable lithium batteries will be 
installed in most makes and models of transport-category airplanes. We 
intend to require special conditions for certification projects 
involving non-rechargeable lithium battery installations to address 
certain safety issues until we can revise the airworthiness 
requirements. Applying special conditions to these installations across 
the range of transport-category airplanes will ensure regulatory 
consistency.
    Typically, the FAA issues special conditions after receiving an 
application for type certificate approval of a novel or unusual design 
feature. However, the FAA has found that the presence of non-
rechargeable lithium batteries in certification projects is not always 
immediately identifiable, because the battery itself may not be the 
focus of the project. Meanwhile, the inclusion of these batteries has 
become virtually ubiquitous on in-production transport category 
airplanes, which shows that there will be a need for these special 
conditions. Also, delaying the issuance of special conditions until 
after each design application is received could lead to costly 
certification delays. Therefore, the FAA finds it necessary to issue 
special conditions applicable to these battery installations on 
particular makes and models of aircraft.
    On April 22, 2016, the FAA published special conditions no. 25-612-
SC in the Federal Register (81 FR 23573) applicable to Gulfstream 
Aerospace Corporation for the Model GVI airplane. Those were the first 
special conditions the FAA issued for non-rechargeable lithium battery 
installations. We explained in that document our decision to make those 
special conditions effective one year after publication in the Federal 
Register, which is April 22, 2017. In those special conditions, the FAA 
stated its intention to apply non-rechargeable lithium battery special 
conditions to design changes on other airplane makes and models applied 
for after this same date.
    Section 1205 of the FAA Reauthorization Act of 1996 requires the 
FAA to consider the extent to which Alaska is not served by 
transportation modes other than aviation, and to establish appropriate 
regulatory distinctions when modifying airworthiness regulations that 
affect intrastate aviation in Alaska. In consideration of this 
requirement and the overall impact on safety, the FAA does not intend 
to require non-rechargeable lithium battery special conditions for 
design changes that only replace a 121.5 megahertz (MHz) emergency-
locator transmitter (ELT) with a 406 MHz ELT that meets Technical 
Standard Order C126b, or later revision, on transport airplanes 
operating only in Alaska. This will support FAA efforts of encouraging 
operators in Alaska to upgrade to a 406 MHz ELT. These ELTs provide 
significantly improved accuracy for

[[Page 464]]

lifesaving services to locate an accident site in Alaskan terrain. The 
FAA considers that the safety benefits from upgrading to a 406 MHz ELT 
for Alaska operations will outweigh the battery fire risk.

Comments Invited

    The substance of these special conditions has been subjected to the 
public-notice and comment period in prior instances and has 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 prior public notice and comment are unnecessary and impracticable, 
and good cause exists for adopting these special conditions upon 
publication in the Federal Register. The FAA is requesting comments to 
allow interested persons to submit views that may not have been 
submitted in response to the prior opportunities for comment described 
above.
    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

    Learjet holds type certificate no. T00008WI, which provides the 
certification basis for the Model 45 airplane. The Model 45 airplane is 
a twin-engine, transport-category airplanes with a passenger seating 
capacity of 9 and a maximum takeoff weight of 20,500 pounds.
    The FAA is issuing these special conditions for non-rechargeable 
lithium battery installations on the Model 45 airplane. The current 
battery requirements in title 14, Code of Federal Regulations (14 CFR) 
part 25 are inadequate for addressing an airplane with non-rechargeable 
lithium batteries.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Learjet must show that the 
Model 45 airplane meets the applicable provisions of the regulations 
listed in type certificate no. T00008WI or the applicable regulations 
in effect on the date of application for the change, except for earlier 
amendments as agreed upon by the FAA. In addition, the certification 
basis includes certain special conditions, exemptions, or later amended 
sections that are not relevant to these special conditions.
    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 Model 45 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 airplane 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 Model 45 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 Feature

    The novel or unusual design feature is the installation of non-
rechargeable lithium batteries.
    For the purpose of these special conditions, we refer to a battery 
and battery system as a battery. A battery system consists of the 
battery and any protective, monitoring, and alerting circuitry or 
hardware inside or outside of the battery. It also includes vents 
(where necessary) and packaging.

Discussion

    The FAA derived the current regulations governing installation of 
batteries in transport-category airplanes from Civil Air Regulations 
(CAR) 4b.625(d), as part of the recodification of CAR 4b that 
established 14 CFR part 25, in February 1965. This recodification 
basically reworded the CAR 4b battery requirements, which are currently 
in Sec.  25.1353(b)(1) through (4). Non-rechargeable lithium batteries 
are novel and unusual with respect to the state of technology 
considered when these requirements were codified. 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.
    Recent events involving rechargeable and non-rechargeable lithium 
batteries prompted the FAA to initiate a broad evaluation of these 
energy storage technologies. In January 2013, two independent events 
involving rechargeable lithium-ion batteries revealed unanticipated 
failure modes. A National Transportation Safety Board (NTSB) letter to 
the FAA, dated May 22, 2014, which is available at http://www.ntsb.gov, 
filename A-14-032-036.pdf, describes these events.
    On July 12, 2013, an event involving a non-rechargeable lithium 
battery in an emergency-locator transmitter installation demonstrated 
unanticipated failure modes. The United Kingdom's Air Accidents 
Investigation Branch Bulletin S5/2013 describes this event.
    Some known uses of rechargeable and non-rechargeable lithium 
batteries on airplanes include:
     Flight deck 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 and 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, 
seatbelt air bags, cabin-management systems, Ethernet switches, routers 
and media servers, wireless systems, internet and in-flight 
entertainment systems, satellite televisions, remotes, and handsets;
     Systems in cargo areas including door controls, sensors, 
video-surveillance equipment, and security systems.
    Some known potential hazards and failure modes associated with non-
rechargeable lithium batteries are:
     Internal failures: In general, these batteries are 
significantly more susceptible to internal failures that can result in 
self-sustaining increases in temperature and pressure (i.e., thermal 
runaway) than their nickel-cadmium or lead-acid counterparts. The 
metallic lithium can ignite, resulting in a self-sustaining fire or 
explosion.
     Fast or imbalanced discharging: Fast discharging or an 
imbalanced discharge of one cell of a multi-cell battery may create an 
overheating condition that results in an

[[Page 465]]

uncontrollable venting condition, which in turn leads to a thermal 
event or an explosion.
     Flammability: Unlike nickel-cadmium and lead-acid 
batteries, lithium batteries use higher energy and current in an 
electrochemical system that can be configured to maximize energy 
storage of lithium. They also use liquid electrolytes that can be 
extremely flammable. The electrolyte, as well as the electrodes, can 
serve as a source of fuel for an external fire if the battery casing is 
breached.
    Special condition no. 1 of these special conditions requires that 
each individual cell within a non-rechargeable lithium battery be 
designed to maintain safe temperatures and pressures. Special condition 
no. 2 addresses these same issues, but for the entire battery. Special 
condition no. 2 requires that the battery be designed to prevent 
propagation of a thermal event, such as self-sustained, uncontrollable 
increases in temperature or pressure from one cell to adjacent cells.
    Special conditions nos. 1 and 2 are intended to ensure that the 
non-rechargeable lithium battery and its cells 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 battery 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 no. 4 makes it clear that the flammable-fluid 
fire protection requirements of Sec.  25.863 apply to non-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. Non-rechargeable lithium batteries contain an 
electrolyte that is a flammable fluid.
    Special condition no. 5 requires that each non-rechargeable lithium 
battery installation 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.
    While special condition no. 5 addresses corrosive fluids and gases, 
special condition no. 6 addresses heat. Special condition no. 6 
requires that each non-rechargeable lithium battery installation has 
provisions to prevent any hazardous effect on airplane structure or 
systems caused by the maximum amount of heat the battery installation 
can generate due to any failure of it or its individual cells. The 
means of meeting special conditions nos. 5 and 6 may be the same, but 
the requirements are independent and address different hazards.
    These special conditions apply to all non-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

    These special conditions are applicable to the Learjet Model 45 
airplane. Should Learjet 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.
    These special conditions are only applicable to design changes 
applied for after the effective date.
    These special conditions are not applicable to changes to 
previously certified non-rechargeable lithium battery installations 
where the only change is either cosmetic, or to relocate the 
installation to improve the safety of the airplane and occupants. 
Previously certified non-rechargeable lithium battery installations, as 
used in this paragraph, are those installations approved for 
certification projects applied for on or before the effective date of 
these special conditions. A cosmetic change is a change in appearance 
only, and does not change any function or safety characteristic of the 
battery installation. These special conditions are also not applicable 
to unchanged, previously certified non-rechargeable lithium battery 
installations that are affected by a change in a manner that improves 
the safety of its installation. The FAA determined that these 
exclusions are in the public interest because the need to meet all of 
the special conditions might otherwise deter these design changes that 
improve safety.

Conclusion

    This action affects only certain a novel or unusual design feature 
on one model of airplane. It is not a rule of general applicability.
    The substance of these special conditions has been subjected to the 
notice and comment period in prior instances and has 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 
prior public notice and comment are unnecessary and impracticable, and 
good cause exists for adopting these special conditions upon 
publication in the Federal Register. The FAA is requesting comments to 
allow interested persons to submit views that may not have been 
submitted in response to the prior opportunities for comment described 
above.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and record keeping 
requirements.

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 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 the Learjet Model 45 airplane.

Non-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, each non-
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.
    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 means for the flightcrew or maintenance personnel to 
determine the

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battery charge state if the battery's function is required for safe 
operation of the airplane.

    Note: A battery system consists of the battery 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 ``battery system'' are referred to as a battery.


    Issued in Renton, Washington, on December 28, 2017.
Suzanne Masterson,
Acting Manager, Transport Standards Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2017-28454 Filed 1-3-18; 8:45 am]
 BILLING CODE 4910-13-P