[Federal Register Volume 81, Number 161 (Friday, August 19, 2016)]
[Rules and Regulations]
[Pages 55351-55353]
[FR Doc No: 2016-19856]

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Rules and Regulations
                                                Federal Register
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Federal Register / Vol. 81, No. 161 / Friday, August 19, 2016 / Rules
and Regulations

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2015-5758; Special Conditions No. 25-632-SC]

Special Conditions: The Boeing Company, Boeing Model 737-8
Airplane; Non-Rechargeable Lithium Battery Installations

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Boeing Company
(Boeing) Model 737-8 airplane. This airplane 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 associated with non-rechargeable
lithium battery installations. 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: Effective April 22, 2017.

FOR FURTHER INFORMATION CONTACT: Nazih Khaouly, Airplane and Flight
Crew Interface Branch, ANM-111, Transport Airplane Directorate,
Aircraft Certification Service, 1601 Lind Avenue SW., Renton,
Washington, 98057-3356; telephone<PHONE_NUMBER>; facsimile<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Future Requests for Installation of Non-Rechargeable Lithium Batteries

    The FAA anticipates that non-rechargeable lithium batteries will be
installed in other makes and models of airplanes. We have determined to
require special conditions for all applications requesting non-
rechargeable lithium battery installations, except the installations
excluded in the Applicability section, until the airworthiness
requirements can be revised to address this issue. Applying special
conditions to these installations across the range of all transport-
airplane makes and models ensures regulatory consistency among
applicants.
    The FAA issued special conditions no. 25-612-SC to Gulfstream
Aerospace Corporation for their GVI airplane. Those are the first
special conditions the FAA issued for non-rechargeable lithium battery
installations. We explained in that document our determination to make
those special conditions effective one year after publication of those
special conditions in the Federal Register, and our intention for other
special conditions for other makes and models to be effective on this
same date or 30 days after their publication, whichever is later.

Background

    On January 27, 2012, Boeing applied for an amendment to type
certificate no. A16WE to include a new Model 737-8 airplane. The Model
737-8 airplane is a twin-engine, transport-category airplane that is a
derivative of the Model 737-800 airplane. The Model 737-8 has a maximum
passenger capacity of 200 and a maximum takeoff weight of 181,200 lbs.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14
CFR) 21.101, Boeing must show that the Model 737-8 airplane meets the
applicable provisions of the regulations listed in type certificate no.
A16WE or the applicable regulations in effect on the date of
application for the change, except for earlier amendments as agreed
upon by the FAA. The regulations listed in the type certificate are
commonly referred to as the ``original type certification basis.'' The
regulations listed in type certificate no. A16WE are 14 CFR part 25
effective February 1, 1965 including Amendments 25-1 through 25-77 with
exceptions listed in the type certificate. In addition, the
certification basis includes other regulations, special conditions, and
exemptions that are not relevant to these special conditions. Type
certificate no. A16WE will be updated to include a complete description
of the certification basis for this airplane model.
    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 737-8 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 737-8 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 Boeing Model 737-8 airplane will incorporate non-rechargeable
lithium batteries.
    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.

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 re-codification of CAR 4b that
established 14 CFR part 25 in February 1965. We basically reworded the
battery requirements, which are currently in Sec.  25.1353(b)(1)
through (4), from the CAR requirements.

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 demonstrated 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 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 1 requires that each individual cell within a
non-rechargeable lithium 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 non-
rechargeable lithium battery and its cells are designed to eliminate
the potential for uncontrolled 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 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
electrolyte that is a flammable fluid.
    Special condition 5 requires each non-rechargeable lithium battery
installation to not damage surrounding structure or adjacent systems,
equipment, or electrical wiring from corrosive fluids or gases that may
escape. Special condition 6 requires each non-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 these special conditions 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.
    These special conditions will apply to all non-rechargeable lithium
battery installations in lieu of Sec.  25.1353(b)(1) through (4) at
Amendment 25-123. Sections 25.1353(b)(1) through (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.

Discussion of Comments

    Notice of proposed special conditions no. 25-16-02-SC, for the
Boeing 737-8 airplane, was published in the Federal Register on
February 11, 2016 [81 FR 7249]. We received two substantive comments.
    The Aerospace Industries Association (AIA) provided several
comments that were identical to their comments for special conditions
no. 25-612-SC (81 FR 23573), which we issued to Gulfstream Aerospace
Corporation for non-rechargeable lithium battery installations on
Gulfstream GVI airplanes. The FAA responded to each of these comments
in that final special conditions document. We incorporated the same
revisions into this Boeing 737-8 special conditions that we
incorporated into the Gulfstream GVI special conditions as a result of
AIA's comments.
    Boeing commented that they fully support AIA's comments.
    Boeing requested that the FAA provide adequate time before non-
rechargeable lithium battery special conditions become effective to
support validation activities by foreign civil airworthiness
authorities (FCAA) and to not adversely impact future airplane
deliveries by all applicants. The FAA considered this same comment from
Boeing for special conditions no. 25-612-SC and provided a detailed
response in that document. We determined the effective date for these
Boeing 737-8 special conditions based on Boeing's comment and other
factors stated in special conditions no. 25-612-SC.
    Boeing commented that the FAA needs to clearly define the
applicability of these special conditions. The FAA concurs. Boeing's
comment is similar to

their comment on special conditions no. 25-612-SC. We provided a
detailed response in special conditions no. 25-612-SC and have now
clearly defined the applicability for these Boeing 737-8 special
conditions. One aspect of Boeing's comment that we did not address in
special conditions no. 25-612-SC is that some design changes may not
change a lithium battery installation but affect it, which results in
these special conditions being applicable. For example, adding a heat
source next to a lithium battery can increase its possibility of
entering into thermal runaway. Lithium battery installations affected
by design changes must meet these special conditions. Some examples of
changes that affect lithium battery installations are those that:
     Increase the temperatures or pressures in a battery,
     Increase the electrical load on a battery,
     Increase potential for imbalance between battery cells,
     Modify protective circuitry for a lithium battery,
     Increase the airplane level risk due to the location of an
existing lithium battery. An example is installation of a new oxygen
line next to an existing part that has a lithium battery. The airplane
level risk may increase due to the potential hazard of a lithium
battery fire in the proximity of oxygen.
    The FAA has determined that ``uncontrolled'' in special condition 2
should be ``uncontrollable'' to more accurately describe the concern.
This revision does not change the intended meaning of this special
condition.
    Except as discussed above, the special conditions are adopted as
proposed.

Applicability

    As discussed above, these special conditions are applicable to the
Model 737-8 airplane. Should the applicant apply at a later date for a
change to the type certificate to include another model incorporating
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 apply to that model as well.
    These special conditions are only applicable to design changes
applied for after the effective date of the special conditions. The
existing airplane fleet and follow-on deliveries of airplanes with
previously certified non-rechargeable lithium battery installations are
not affected.
    These special conditions are not applicable to previously certified
non-rechargeable lithium battery installations where the only change is
either cosmetic or relocating the installation to improve the safety of
the airplane and occupants. The FAA determined that this exclusion is
in the public interest because the need to meet all of the special
conditions might otherwise deter such design changes that involve
relocating batteries. A cosmetic change is a change in appearance only,
and does not change any function or safety characteristic of the
battery installation.

Conclusion

    This action affects only certain novel or unusual design features
on one model of airplane. It is not a rule of general applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping
requirements.

0
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, the following special conditions are part of the type
certification basis for the Boeing Model 737-8 airplane.

Non-Rechargeable Lithium Battery Installations

    In lieu of Sec.  25.1353(b)(1) through (b)(4) at Amendment 25-123,
each non-rechargeable lithium battery installation must:
    1. Maintain safe cell temperatures and pressures under all
foreseeable operating conditions to prevent fire and explosion.
    2. 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 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 August 12, 2016.
Michael Kaszycki,
Assistant Manager, Transport Airplane Directorate, Aircraft
Certification Service.
[FR Doc. 2016-19856 Filed 8-18-16; 8:45 am]
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