[Federal Register Volume 79, Number 6 (Thursday, January 9, 2014)]
[Rules and Regulations]
[Pages 1591-1593]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-00172]
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Rules and Regulations
Federal Register
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This section of the FEDERAL REGISTER contains regulatory documents
having general applicability and legal effect, most of which are keyed
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Federal Register / Vol. 79, No. 6 / Thursday, January 9, 2014 / Rules
and Regulations
[[Page 1591]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2013-0763; Special Conditions No. 25-514-SC]
Special Conditions: Learjet Model 35, 35A, 36, and 36A Airplanes;
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 the Learjet Model 35,
35A, 36, and 36A airplanes. These airplanes, as modified by Peregrine,
13000 E. Control Tower Road, Unit K-4, Englewood, CO, 80112, will have
a novel or unusual design feature associated with 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: February 10, 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 June 29, 2012, Peregrine applied for a supplemental type
certificate for installing equipment that uses rechargeable lithium-ion
battery systems in Learjet Model 35, 35A, 36, and 36A airplanes. The
Learjet Model 35, 35A, 36, and 36A airplanes are small transport-
category airplanes powered by two turbojet engines, with maximum
takeoff weights of up to 18,000 pounds. These airplanes operate with a
two-pilot crew and can seat up to eight passengers. The Learjet Model
35, 35A, 36, and 36A airplanes are powered by two Garrett TF731-2-2B
engines, and are equipped with an emergency power supply and software-
configurable avionics.
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, Peregrine must show that the
Learjet Model 35, 35A, 36, and 36A airplanes, as changed, continue to
meet the applicable provisions of the regulations incorporated by
reference in Type Certificate No. A10CE or the applicable regulations
in effect on the date of application for the change. The regulations
incorporated by reference in the type certificate are commonly referred
to as the ``original type certification basis.'' The regulations
incorporated by reference in Type Certificate No. A10CE are as follows:
Title 14, Code of Federal Regulations part 25, effective February
1, 1965, as amended by Amendments 25-1, 25-2, 25-4, 25-7, 25-18, and
Sec. 25.571(d) of Amendment 25-10; Special Conditions set forth in FAA
letter to Learjet dated March 1, 1967; Special Conditions No. 25-50-CE-
6 dated April 18, 1973, and Amendment 1 dated September 18, 1973. The
certification basis for Models 35A and 36A also includes Special
Conditions No. 25-72-CE-8 dated November 3, 1976, and Amendment 1 dated
March 14, 1978. The certification basis for Model 35A, in addition to
the basis listed above, includes Special Conditions 25-ANM-28 dated May
3, 1989. In addition, the certification basis includes certain later
amended sections of the applicable part 25 regulations that are not
relevant to these special conditions.
If the regulations incorporated by reference do not provide
adequate standards regarding the change, the applicant must comply with
certain regulations in effect on the date of application for the
change.
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 Learjet Model 35, 35A, 36, and 36A
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 applicant apply for a supplemental type
certificate to modify any other model included on the same type
certificate, to incorporate 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 Learjet Model 35, 35A, 36, and 36A 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. 21.101.
[[Page 1592]]
Novel or Unusual Design Features
The Learjet Model 35, 35A, 36, and 36A airplanes will incorporate
the following novel or unusual design features: A Mid-Continent MD835-5
Emergency Power Supply that uses a rechargeable lithium-ion battery and
battery system. Lithium-ion batteries and battery systems have certain
failure, operational, and maintenance characteristics that differ
significantly from those of the nickel-cadmium and lead-acid
rechargeable batteries. Rechargeable lithium-ion batteries and battery
systems are considered to be a novel or unusual design feature in
transport-category airplanes, with respect to the requirements in 14
CFR 25.1353.
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 the Learjet Model 35, 35A, 36, and 36A
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 MD835-5 Emergency Power Supply
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 special conditions is to establish
appropriate airworthiness standards for lithium-ion battery
installations in the Learjet Model 35, 35A, 36, and 36A airplanes and
to ensure, as required by Sec. Sec. 25.1309 and 25.601, that these
lithium-ion batteries and battery systems are not hazardous or
unreliable. 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.
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 numerous other aircraft,
including Boeing Model 787 (72FR57842; October 11, 2007).
Discussion of Comments
Notice of proposed special conditions no. 25-13-07-SC for the
Peregrine modifications to the Learjet Model 35, 35A, 36, and 36A
airplanes was published in the Federal Register on October 22, 2013 (78
FR 62495). No comments were received, and the special conditions are
adopted as proposed.
Applicability
As discussed above, these special conditions are applicable to the
Learjet Model 35, 35A, 36, and 36A airplanes. Should Peregrine apply at
a later date for a supplemental type certificate to modify any other
model included on Type Certificate No. A10CE, to incorporate 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 the Learjet Model 35, 35A, 36, and 36A airplanes. It is not a rule
of general applicability and it affects only the applicant who applied
to the FAA for approval of these features on the airplane.
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, 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 35, 35A, 36, and 36A
airplanes modified by Peregrine.
These special conditions require that (1) all characteristics of
the rechargeable lithium-ion batteries and battery systems, and their
installation, that
[[Page 1593]]
could affect safe operation of the Learjet Model 35, 35A, 36, and 36A
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.
In lieu of the requirements of 14 CFR 25.1353(b)(1) through (b)(4)
at Amendment 25-113, the following special conditions apply.
Rechargeable lithium-ion batteries and battery systems on Learjet Model
35, 35A, 36, and 36A 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 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 Amendment 25-113 in the certification basis for
Learjet Model 35, 35A, 36, and 36A 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 25-113 remain in effect for batteries and
battery installations on Learjet Model 35, 35A, 36, and 36A
airplanes that do not use rechargeable lithium-ion batteries.
Issued in Renton, Washington, on December 31, 2013.
Angelos Xidias,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2014-00172 Filed 1-8-14; 8:45 am]
BILLING CODE 4910-13-P