[Federal Register Volume 72, Number 196 (Thursday, October 11, 2007)]
[Rules and Regulations]
[Pages 57842-57844]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-19980]
[[Page 57842]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM375 Special Conditions No. 25-359-SC]
Special Conditions: Boeing Model 787-8 Airplane; Lithium Ion
Battery Installation
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions.
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SUMMARY: These special conditions are issued for the Boeing Model 787-8
airplane. This airplane will have novel or unusual design features when
compared to the state of technology envisioned in the airworthiness
standards for transport category airplanes. The Boeing Model 787-8
airplanes will use high capacity lithium ion battery technology in on-
board systems. For these design features, the applicable airworthiness
regulations do not contain adequate or appropriate safety standards.
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 standards. Additional
special conditions will be issued for other novel or unusual design
features of the Boeing Model 787-8 airplanes.
DATES: Effective Date: November 13, 2007.
FOR FURTHER INFORMATION CONTACT: Nazih Khaouly, FAA, Airplane and
Flight Crew Interface, 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 March 28, 2003, Boeing applied for an FAA type certificate for
its new Boeing Model 787-8 passenger airplane. The Boeing Model 787-8
airplane will be an all-new, two-engine jet transport airplane with a
two-aisle cabin. The maximum takeoff weight will be 476,000 pounds,
with a maximum passenger count of 381 passengers.
Type Certification Basis
Under provisions of 14 Code of Federal Regulations (CFR) 21.17,
Boeing must show that Boeing Model 787-8 airplanes (hereafter referred
to as ``the 787'') meet the applicable provisions of 14 CFR part 25, as
amended by Amendments 25-1 through 25-117, except Sec. Sec. 25.809(a)
and 25.812, which will remain at Amendment 25-115. If the Administrator
finds that the applicable airworthiness regulations do not contain
adequate or appropriate safety standards for the 787 because of a novel
or unusual design feature, special conditions are prescribed under
provisions of 14 CFR 21.16.
In addition to the applicable airworthiness regulations and special
conditions, the 787 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 must also issue a finding of regulatory
adequacy pursuant to section 611 of Public Law 92-574, the ``Noise
Control Act of 1972.''
The FAA issues special conditions, as defined in 14 CFR 11.19,
under Sec. 11.38, and they become part of the type certification basis
under Sec. 21.17(a)(2).
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 or similar
novel or unusual design feature, the special conditions would also
apply to the other model under Sec. 21.101.
Novel or Unusual Design Features
The 787 will incorporate a number of novel or unusual design
features. Because of rapid improvements in airplane technology, the
applicable airworthiness regulations do not contain adequate or
appropriate safety standards for these design features. These special
conditions for the 787 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.
The 787 design includes planned use of lithium ion batteries for
the following applications:
Main and Auxiliary Power Unit (APU) Battery/Battery
Charger System.
Flight Control Electronics.
Emergency Lighting System.
Recorder Independent Power Supply.
Large, high capacity, rechargeable lithium ion batteries are a novel or
unusual design feature in transport category airplanes. 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 large transport category airplanes. The FAA issues
these special conditions to require that (1) all characteristics of the
lithium ion battery and its installation that could affect safe
operation of the 787 are addressed, and (2) appropriate maintenance
requirements are established to ensure the availability of electrical
power from the batteries when needed.
Background
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, 14 CFR 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. This led
to additional rulemaking affecting large transport category airplanes
as well as small airplanes. On September 1, 1977, and March 1, 1978,
respectively, the FAA issued 14 CFR 25.1353c(5) and c(6), governing
nickel-cadmium battery installations on large transport category
airplanes.
The proposed use of lithium ion batteries for the emergency
lighting system on the 787 has prompted the FAA to review the adequacy
of these existing regulations. Our review indicates that existing
regulations do not adequately address several failure, operational, and
maintenance characteristics of lithium ion batteries that could affect
the safety and reliability of the 787's lithium ion battery
installations.
At present, there is limited experience with use of rechargeable
lithium ion batteries in applications involving commercial aviation.
However, other users of this technology, ranging from wireless
telephone manufacturing to the electric vehicle industry, have noted
safety problems with lithium ion batteries. These problems include
overcharging, over-discharging, and flammability of cell components.
1. Overcharging
In general, lithium ion batteries are significantly more
susceptible to internal failures that can result in self-sustaining
increases in temperature and pressure (thermal runaway) than their
nickel-cadmium or lead-acid counterparts. This is especially true for
overcharging, which causes heating and destabilization of the
components of the cell, leading to formation (by plating) of highly
unstable metallic lithium. The metallic lithium can ignite, resulting
in
[[Page 57843]]
a self-sustaining fire or explosion. Finally, the severity of thermal
runaway from overcharging increases with increasing battery capacity,
because of the higher amount of electrolytes in large batteries.
2. Over-Discharging
Discharge of some types of lithium ion batteries 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. This is 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 use liquid electrolytes that are flammable. The
electrolytes can serve as a source of fuel for an external fire, if
there is a breach of the battery container.
These problems experienced by users of lithium ion batteries raise
concern about use of these batteries in commercial aviation. The intent
of these special conditions is to establish appropriate airworthiness
standards for lithium ion battery installations in the 787 and to
ensure, as required by 14 CFR 25.601, that these battery installations
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 special conditions adopted for
the Airbus A380 (71 FR 74755; December 13, 2006).
Discussion of Comments
Notice of Proposed Special Conditions No. 25-07-10-SC for the 787
was published in the Federal Register on April 30, 2007 (72 FR 21162).
We received comments from the Air Line Pilots Association,
International, which are discussed below.
The Air Line Pilots Association (ALPA) conditionally supports the
FAA's proposal for special conditions for lithium ion batteries on the
787 aircraft, but ``strongly maintains that there need to be adequate
protections and procedures in place to ensure that concerns regarding
lithium ion batteries are fully addressed and protected against.''
Appended to the ALPA comments was a copy of FAA report DOT/FAA/AR-06/
38, September 2006, Flammability Assessment of Bulk-Packed,
Rechargeable Lithium-Ion Cells In Transport Category Aircraft. With the
knowledge of the safety hazards described in the appended report and by
others, ALPA requested that the FAA consider the specific concerns
discussed below.
ALPA Comment re Special Condition (3): The commenter
requested that paragraph 3 of the special conditions be revised to
ensure that the certification design of the 787 prevents explosive or
toxic gases emitted by a lithium ion battery from entering the cabin.
The commenter also requested that the FAA ensure that flightcrew
procedures and training are adequate to protect both passengers and
crew, if explosive or toxic gases do enter the cabin.
FAA Response: 14 CFR 25.857 prohibits hazardous quantities of
smoke, flames, or extinguishing agents from cargo compartments from
entering any compartment occupied by the crew or passengers. Paragraph
(3) of these special conditions specifies that
No explosive or toxic gases emitted by any lithium ion battery
in normal operation, or as the result of any failure of the battery
charging system, monitoring system, or battery installation not
shown to be extremely remote, may accumulate in hazardous quantities
within the airplane.
The special conditions require that any explosive or toxic gases
emitted by a lithium ion battery be limited to less than hazardous
quantities everywhere on the airplane. The FAA does not expect the need
for additional training above and beyond the training that crews
receive today. We made no change to these special conditions as a
result of this comment.
ALPA Comment re Special Condition (4): The commenter
stated,
We are very concerned with a fire erupting in flight, and being
able to rapidly extinguish it. The Special Conditions should require
that there be a means provided to apply extinguishing agents by the
flight (cabin) crew instead of promoting it as an option in managing
the threat posed by the use of lithium-ion batteries. ALPA maintains
that the petitioner must provide means for extinguishing fires that
occur vs. listing it as an option in Sec. 25.863.
ALPA clarified this comment in the following communication, sent by e-
mail on August 10, 2007.
The intent of our comments submitted to the Docket for question
[Special Condition] Number 4 (see below) is to assure that the FAA
includes language or makes it clear in the Special Conditions
directing the OEM or a potential STC applicant that a fire from
these devices, in any situation, is unacceptable. ALPA requests the
FAA reiterate that preventing a fire and not reacting to one, if one
occurs, is critical. The last sentence of our comments in this
Question [Special Condition] refers to the potential for an
``equivalent level of safety'' being introduced or referenced in the
document that would negate the prevention of a fire; ALPA finds this
``option'' unacceptable.
(4) Installations of lithium ion batteries must meet the
requirements of 14 CFR 25.863(a) through (d).
The proposal states that the certification requirements of Sec.
25.283 [Sec. 25.863] must be complied with; however, the FAA report
(FAA report DOT/FAA/AR-06/38, September 2006) indicates that a
relatively small fire source is sufficient to heat the lithium-ion
cell above the temperature required to activate the pressure release
mechanism in the cell. This causes the cell to forcefully vent its
electrolyte through the relief ports near the positive terminal. The
electrolyte is highly flammable and easily ignites when exposed to
an open flame or hot surface. Fully charged cells released small
white sparks along with the electrolyte.
FAA Response: The FAA shares the commenter's concern over a fire
erupting in flight. The regulations and the rigid requirements defined
in these special conditions are intended to prevent lithium battery
fires on board the aircraft. We have made no change as a result of this
comment.
ALPA Comment re Special Condition (7): The commenter
suggested that the special conditions address means to ensure that the
lithium ion batteries do not overheat or overcharge in the event of
failure or malfunction of the automatic disconnect function, when a
means of disconnecting the batteries from the charging source is not
available.
FAA Response: The FAA agrees with the commenter. Special Condition
(7) requires means to prevent overheating or overcharging of lithium
ion batteries in the event of failure or malfunction of the automatic
disconnect function. The issue of failure modes of the lithium ion
batteries is covered by Special Conditions (1), (2), and (6). We made
no change as a result of this comment.
[[Page 57844]]
ALPA Comment re Special Condition (8): Finally, ALPA
commented on monitoring and warning features that will indicate when
the state-of-charge of the batteries has fallen below levels considered
acceptable for dispatch of the airplane. The commenter suggested that
the special conditions address the location of the warning indication;
whether it is displayed to the captain, the crew, or both; and the
training to be incorporated in the crew training programs.
FAA Response: Flight deck warning indicators associated with the
state-of-charge of the lithium ion battery and appropriate training of
the crew will be addressed during certification as part of the flight
deck evaluation. As required by Sec. 25.1309(c), this evaluation will
ensure that the warning indication is effective and appropriate for the
hazard. We made no change as a result of this comment.
These special conditions are issued as proposed.
Applicability
As discussed above, these special conditions are applicable to the
787. Should Boeing apply at a later date for a change to the type
certificate to include another model on the same type certificate
incorporating the same novel or unusual design features, these special
conditions would apply to that model as well.
Conclusion
This action affects only certain novel or unusual design features
of the 787. 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 the Boeing Model 787-8 airplane.
In lieu of the requirements of 14 CFR 25.1353(c)(1) through (c)(4),
the following special conditions apply. Lithium ion batteries on the
Boeing Model 787-8 airplane 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 lithium ion battery installation must preclude
explosion in the event of those failures.
(2) Design of the lithium ion batteries must preclude the
occurrence of self-sustaining, uncontrolled increases in temperature or
pressure.
(3) No explosive or toxic gases emitted by any lithium ion battery
in normal operation, or as the result of any failure of the battery
charging system, monitoring system, or battery installation not shown
to be extremely remote, may accumulate in hazardous quantities within
the airplane.
(4) Installations of lithium ion batteries must meet the
requirements of 14 CFR 25.863(a) through (d).
(5) No corrosive fluids or gases that may escape from any lithium
ion battery 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 14
CFR 25.1309(b) and applicable regulatory guidance.
(6) Each lithium ion battery installation 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) Lithium ion battery installations must have a system to control
the charging rate of the battery automatically, 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 lithium ion battery installation whose function is 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 14 CFR
25.1529 must contain maintenance requirements for measurements of
battery capacity at appropriate intervals to ensure that batteries
whose function is required for safe operation of the airplane will
perform their intended function as long as the battery is installed in
the airplane. The Instructions for Continued Airworthiness must also
contain procedures for the maintenance of lithium ion batteries in
spares storage to prevent the replacement of batteries whose function
is required for safe operation of the airplane with batteries that have
experienced degraded charge retention ability or other damage due to
prolonged storage at a low state of charge.
Note: These special conditions are not intended to replace 14
CFR 25.1353(c) in the certification basis of the Boeing 787-8
airplane. These special conditions apply only to lithium ion
batteries and their installations. The requirements of 14 CFR
25.1353(c) remain in effect for batteries and battery installations
of the Boeing 787-8 airplane that do not use lithium ion batteries.
Issued in Renton, Washington, on September 28, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-19980 Filed 10-10-07; 8:45 am]
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