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[Federal Register Volume 79, Number 162 (Thursday, August 21, 2014)]
[Rules and Regulations]
[Pages 49423-49426]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-19821]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2013-0801; Special Conditions No. 25-562-SC]

Special Conditions: Airbus Model A350-900 Airplanes; Permanently 
Installed Rechargeable Lithium-Ion Batteries and Battery Systems

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for Airbus Model A350-900 
airplanes. This airplane will have a novel or unusual design feature 
associated with permanently installed rechargeable lithium-ion 
batteries and battery systems. These batteries have 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 large 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: Effective date: September 22, 2014.

FOR FURTHER INFORMATION CONTACT: Nazih Khaouly, FAA, Airplane and 
Flight Crew Interface Branch, ANM-111, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW., Renton, 
Washington 98057-3356; telephone 425-227-2432; facsimile 425-227-1149.

SUPPLEMENTARY INFORMATION:

Background

    On August 25, 2008, Airbus applied for a type certificate for their 
new Model A350-900 series airplane. Later, Airbus requested, and the 
FAA approved, an extension to the application for FAA type 
certification to November 15, 2009. The Model A350-900 series has a 
conventional layout with twin wing-mounted Rolls-Royce Trent XWB 
engines. It features a twin aisle, 9-

[[Page 49424]]

abreast, economy-class layout, and accommodates side-by-side placement 
of LD-3 containers in the cargo compartment. The basic Model A350-900 
series configuration accommodates 315 passengers in a standard two-
class arrangement. The design cruise speed is Mach 0.85 with a maximum 
take-off weight of 602,000 lbs.
    Existing airworthiness regulations did not anticipate the use of 
lithium-ion batteries and battery systems on aircraft. Lithium-ion 
batteries and battery systems have new hazards that were not 
contemplated when the existing regulations were issued. In Title 14, 
Code of Federal Regulations (14 CFR) 25.1353, the FAA provided an 
airworthiness standard for lead-acid batteries and nickel-cadmium 
batteries. These special conditions provide an equivalent level of 
safety as that of the existing regulation. The current regulations are 
not adequate for rechargeable lithium-battery and battery system 
installations. Additional lithium-battery and battery system special 
conditions are required to ensure the same level of safety as set forth 
by the existing regulation intended for other battery technology.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, Airbus must show that the 
Model A350-900 series meets the applicable provisions of 14 CFR part 
25, as amended by Amendments 25-1 through 25-129.
    The FAA has determined that Airbus Model A350-900 series airplanes 
must comply with the following sections: Sec.  25.863(a) through (d), 
Amendment 25-61 and Amendment 25-66.
    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 A350-900 series because of a 
novel or unusual design feature, special conditions are prescribed 
under Sec.  21.16.
    Special conditions are initially applicable to the model or series 
for which they are issued. Should the type certificate for that model 
be amended later to include any other model that incorporates the same 
or similar novel or unusual design feature, the 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 A350-900 airplane must comply with the 
fuel-vent and exhaust-emission requirements of 14 CFR part 34, the 
noise-certification requirements of 14 CFR part 36, and the FAA must 
issue a finding of regulatory adequacy under section 611 of Public Law 
92-574, the ``Noise Control Act of 1972.''
    The FAA issues special conditions, as defined in Sec.  11.19, under 
Sec.  11.38, and they become part of the type-certification basis under 
Sec.  21.17(a)(2).

Novel or Unusual Design Features

    The Airbus Model A350-900 airplane will incorporate the following 
novel or unusual design features: Permanently installed rechargeable 
lithium batteries and lithium battery systems.

Discussion

    The current regulations governing installation of batteries in 
large transport-category airplanes were derived from Civil Air 
Regulations (CAR) part 4b.625(d) as part of the re-codification of CAR 
4b that established 14 CFR part 25 in February 1965. The new battery 
requirements, Sec.  25.1353(c)(1) through (c)(4), basically reworded 
the CAR requirements.
    Increased use of nickel-cadmium batteries in small airplanes 
resulted in increased incidents of battery fires and failures which led 
to additional rulemaking affecting large transport-category airplanes 
as well as small airplanes. On September 1, 1977 and March 1, 1978, the 
FAA issued Sec.  25.1353(c)(5) and (c)(6), respectively, governing 
nickel-cadmium battery installations on large transport-category 
airplanes.
    The proposed use of lithium-ion batteries and battery systems for 
equipment and systems on Airbus Model A350 airplanes has prompted the 
FAA to review the adequacy of these existing regulations. Our review 
indicates that the existing regulations do not adequately address 
several failure, operational, and maintenance characteristics of 
lithium-ion batteries and battery systems that could affect the safety 
and reliability of the Airbus model A350-900 airplane rechargeable 
lithium batteries and rechargeable lithium-battery-system 
installations.
    At present, commercial aviation has limited experience with use of 
rechargeable lithium-ion batteries and battery systems in applications 
involving commercial aviation. However, other users of this technology, 
ranging from wireless telephone manufacturers to the electric-vehicle 
industry, have noted potential hazards with lithium-ion batteries and 
battery systems. These problems include overcharging, over-discharging, 
and flammability of cell components.

1. Overcharging

    In general, lithium-ion batteries and battery systems 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. This 
condition is especially true for overcharging, which causes heating and 
destabilization of the components of the cell, leading to the formation 
(by plating) of highly unstable metallic lithium. The metallic lithium 
can ignite, resulting in a self-sustaining fire or explosion. Finally, 
the severity of thermal runaway, due to overcharging, increases with 
increasing battery capacity due to the higher amount of electrolyte in 
large batteries.

2. Over-Discharging

    Discharge of some types of lithium-ion batteries and battery 
systems, beyond a certain voltage (typically 2.4 volts), can cause 
corrosion of the electrodes of the cell, resulting in loss of battery 
capacity that cannot be reversed by recharging. This loss of capacity 
may not be detected by the simple voltage measurements commonly 
available to flightcrews as a means of checking battery status--a 
problem shared with nickel-cadmium batteries.

3. Flammability of Cell Components

    Unlike nickel-cadmium and lead-acid batteries, some types of 
lithium-ion batteries and battery systems use liquid electrolytes that 
are flammable. The electrolyte can serve as a source of fuel for an 
external fire if there is a breach of the battery container.
    The problems lithium-ion battery and battery-system users 
experience raise concern about the use of these batteries in commercial 
aviation. The intent of the proposed special conditions is to establish 
appropriate airworthiness standards for lithium-ion battery 
installations in Airbus Model A350-900 airplanes and to ensure, as 
required by Sec. Sec.  25.1309 and 25.601, that these lithium-ion 
batteries and battery systems will not result in an unsafe condition. 
To address these concerns, these special conditions adopt the following 
requirements:
     Those sections of 14 CFR 25.1353 that are applicable to 
lithium ion batteries.
     The flammable fluid fire protection requirements of 14 CFR 
25.863. In the past, this rule was not applied to batteries of 
transport category airplanes, since the electrolytes used in lead-acid 
and nickel-cadmium batteries are not flammable.

[[Page 49425]]

     New requirements to address the hazards of overcharging 
and over-discharging that are unique to lithium ion batteries.
     New maintenance requirements to ensure that batteries used 
as spares are maintained in an appropriate state of charge.
    These special conditions are similar to lithium-ion batteries and 
battery systems special conditions adopted for the Boeing Model 787 
(72FR57842; October 11, 2007).
    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. 25-13-41-SC for the 
Airbus Model A350-900 series airplane was published in the Federal 
Register on December 19, 2013 (78 FR 76772). No comments were received, 
and the special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Airbus Model A350-900 series airplanes. Should Airbus apply later for a 
change to the type certificate to include another model incorporating 
the same novel or unusual design feature, the special conditions would 
apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on Airbus Model A350-900 series airplanes. It is not a rule of general 
applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
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

0
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 Airbus Model A350-900 airplanes.
    The following special conditions apply to all rechargeable lithium-
ion batteries and battery systems on Airbus Model A350-900 airplanes, 
in lieu of the requirements of Sec.  25.1353(b)(1) through (b)(4) at 
Amendment 25-123.
    These special conditions require that (1) all characteristics of 
the rechargeable lithium-ion batteries and battery systems, and their 
installation, that could affect safe operation of Airbus Model A350-900 
airplanes, are addressed, and (2) appropriate Instructions for 
Continued Airworthiness, which include maintenance requirements, are 
established to ensure the availability of electrical power, when 
needed, from the batteries.
    Rechargeable lithium-ion batteries and battery systems on Airbus 
Model A350-900 airplanes must be designed and installed as follows:
    1. Safe cell temperatures and pressures must be maintained during 
any foreseeable charging or discharging condition, and during any 
failure of the charging or battery monitoring system not shown to be 
extremely remote. The rechargeable lithium-ion batteries and battery 
systems must preclude explosion in the event of those failures.
    2. Design of the rechargeable lithium-ion batteries and battery 
systems must preclude the occurrence of self-sustaining, uncontrolled 
increases in temperature or pressure.
    3. No explosive or toxic gases emitted by any rechargeable lithium-
ion batteries and battery systems in normal operation, or as the result 
of any failure of the battery charging system, monitoring system, or 
battery installation that is not shown to be extremely remote, may 
accumulate in hazardous quantities within the airplane.
    4. Installations of rechargeable lithium-ion batteries and battery 
systems must meet the requirements of Sec.  25.863(a) through (d).
    5. No corrosive fluids or gases that may escape from any lithium-
ion batteries and battery systems may damage surrounding structure or 
any adjacent systems, equipment, or electrical wiring of the airplane 
in such a way as to cause a major or more severe failure condition, in 
accordance with Sec.  25.1309 (b) and applicable regulatory guidance.
    6. Each rechargeable lithium-ion battery and battery system must 
have provisions to prevent any hazardous effect on structure or 
essential systems caused by the maximum amount of heat the battery can 
generate during a short circuit of the battery or of its individual 
cells.
    7. Rechargeable lithium-ion batteries and battery systems must have 
a system to automatically control the charging rate of the battery, so 
as to prevent battery overheating or overcharging, and:
    i. A battery-temperature sensing and over-temperature warning 
system with a means for automatically disconnecting the battery from 
its charging source in the event of an over-temperature condition, or,
    ii. A battery-failure sensing and warning system with a means for 
automatically disconnecting the battery from its charging source in the 
event of battery failure.
    8. Any rechargeable lithium-ion batteries and battery systems, the 
function of which are required for safe operation of the airplane, must 
incorporate a monitoring and warning feature that will provide an 
indication to the appropriate flight crewmembers whenever the state-of-
charge of the batteries has fallen below levels considered acceptable 
for dispatch of the airplane.
    9. The Instructions for Continued Airworthiness required by Sec.  
25.1529 must contain maintenance requirements to assure that the 
lithium-ion batteries are sufficiently charged at appropriate intervals 
specified by the battery manufacturer and the equipment manufacturer of 
the rechargeable lithium-ion battery or rechargeable lithium-ion 
battery system. This is required to ensure that rechargeable lithium-
ion batteries and battery systems will not degrade below specified 
ampere-hour levels sufficient to power the aircraft system, for 
intended applications. The Instructions for Continued Airworthiness 
must also contain procedures for the maintenance of batteries in spares 
storage to prevent the replacement of batteries with batteries that 
have experienced degraded charge-retention ability or other damage due 
to prolonged storage at a low state of charge. Replacement batteries 
must be of the same manufacturer and part number as approved by the 
FAA. Precautions should be included in the Instructions for Continued 
Airworthiness maintenance instructions to prevent mishandling of the 
rechargeable lithium-ion batteries and battery systems, which could 
result in short-circuit or other unintentional impact damage caused by 
dropping or other destructive means.

    Note 1:  The term ``sufficiently charged''' means that the 
battery will retain enough of a charge, expressed in ampere-hours, 
to ensure that the battery cells will not be damaged. A battery cell 
may be damaged by lowering the charge below a point where the 
battery experiences a reduction in the ability to charge and retain 
a full charge. This reduction would be greater than the reduction 
that may result from normal operational degradation.

    Note 2: These special conditions are not intended to replace 
Sec.  25.1353(b) at

[[Page 49426]]

Amendment 25-123 in the certification basis for Airbus Model A350-
900 airplanes. These special conditions apply only to rechargeable 
lithium-ion batteries and battery systems and their installations. 
The requirements of Sec.  25.1353(b) at Amendment 25-123 remain in 
effect for batteries and battery installations on Airbus Model A350-
900 airplanes that do not use rechargeable lithium-ion batteries.

    Issued in Renton, Washington, on July 30, 2014.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2014-19821 Filed 8-20-14; 8:45 am]
BILLING CODE 4910-13-P
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