[Federal Register Volume 72, Number 82 (Monday, April 30, 2007)]
[Proposed Rules]
[Pages 21162-21164]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-8186]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM375 Special Conditions No. 25-07-10-SC]


Special Conditions: Boeing Model 787-8 Airplane; Lithium Ion 
Battery Installation

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This notice proposes special conditions 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 this design feature, the applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards. These proposed 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. Additional special conditions will be 
issued for other novel or unusual design features of the Boeing Model 
787-8 airplanes.

DATES: Comments must be received on or before June 14, 2007.

ADDRESSES: Comments on this proposal may be mailed in duplicate to: 
Federal Aviation Administration, Transport Airplane Directorate, 
Attention: Rules Docket (ANM-113), Docket No. NM375, 1601 Lind Avenue, 
SW., Renton, Washington 98057-3356; or delivered in duplicate to the 
Transport Airplane Directorate at the above address. All comments must 
be marked Docket No. NM375. Comments may be inspected in the Rules 
Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Nazih Khaouly, FAA, Airplane & 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:

Comments Invited

    The FAA invites interested persons to participate in this 
rulemaking by submitting written comments, data, or views. The most 
helpful comments reference a specific portion of the special 
conditions, explain the reason for any recommended change, and include 
supporting data. We ask that you send us two copies of written 
comments.
    We will file in the docket all comments we receive as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning these proposed special conditions. The docket is available 
for public inspection before and after the comment closing date. If you 
wish to review the docket in person, go to the address in the ADDRESSES 
section of this notice between 7:30 a.m. and 4 p.m., Monday through 
Friday, except Federal holidays.
    We will consider all comments we receive on or before the closing 
date for comments. We will consider comments filed late if it is 
possible to do so without incurring expense or delay. We may change the 
proposed special conditions based on comments we receive.
    If you want the FAA to acknowledge receipt of your comments on this 
proposal, include with your comments a pre-addressed, stamped postcard 
on which the docket number appears. We will stamp the date on the 
postcard and mail it back to you.

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 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 part 36. In addition, the FAA must issue a finding of regulatory 
adequacy pursuant to section 611 of Public Law 92-574, the ``Noise 
Control Act of 1972.''
    Special conditions, as defined in Sec.  11.19, are issued in 
accordance with Sec.  11.38 and become part of the type certification 
basis in accordance with 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 the provisions of 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 proposed 
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

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installation on large transport category airplanes. The FAA is 
proposing this special condition 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 
installation.
    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 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 proposed 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 proposed 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 proposed special conditions are similar to special conditions 
adopted for the Airbus A380 (71 FR 74755); December 13, 2006).

Applicability

    As discussed above, these proposed 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 incorporating the same 
novel or unusual design features, these proposed special conditions 
would apply to that model as well under the provisions of Sec.  21.101.

Conclusion

    This action would affect only certain novel or unusual design 
features of the 787. It is not a rule of general applicability, and it 
would affect only the applicant that 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.

    The authority citation for these Special Conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

The Proposed Special Conditions

    Accordingly, the Administrator of the Federal Aviation 
Administration (FAA) proposes the following special conditions 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.

[[Page 21164]]

    (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 April 23, 2007.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-8186 Filed 4-27-07; 8:45 am]
BILLING CODE 4910-13-P