[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]



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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

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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.

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     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]
BILLING CODE 4910-13-P