[Federal Register Volume 75, Number 69 (Monday, April 12, 2010)]
[Rules and Regulations]
[Pages 18399-18402]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-8218]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM426; Special Conditions No. 25-404-SC]


Special Conditions: Modification to Boeing Model 737-600/-700/-
700C/-800/-900 and -900ER Series Airplanes: Rechargeable Lithium 
Batteries and Rechargeable Lithium-Battery Systems

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Boeing 737-600/-
700/-700C/-800/-900 and -900ER Series airplanes (hereafter referred to 
as ``Boeing 737NG''). These airplanes, as modified by the Boeing 
Company, will have a novel or unusual design feature associated with 
the installation of rechargeable lithium batteries and rechargeable 
lithium-battery systems. 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: The effective date of these special conditions is April 5, 2010. 
We must receive your comments by May 27, 2010.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attn: Rules 
Docket (ANM-113), Docket No. NM426, 1601 Lind Avenue SW., Renton, 
Washington, 98057-3356. You may deliver two copies to the Transport 
Airplane Directorate at the above address. You must mark your comments: 
Docket No. NM426. You can inspect comments in the Rules Docket 
weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Nazih Khaouly, ANM-111, Transport 
Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue 
SW., Renton, Washington, 98057-3356; telephone (425) 227-2432; 
facsimile (425) 227-1320.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice of, and 
opportunity for prior public comment on, these special conditions are 
impracticable because these procedures

[[Page 18400]]

would significantly delay issuance of the design approval, and thus 
delivery, of the affected aircraft. In addition, the substance of these 
special conditions has been subject to the public-comment process in 
several prior instances with no substantive comments received. The FAA 
therefore finds that good cause exists for making these special 
conditions effective upon issuance.

Comments Invited

    We invite interested people to take part in this rulemaking by 
sending written comments, data, or views. The most helpful comments 
reference a specific portion of the special conditions, explain the 
reasons for recommended changes, 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 
about these special conditions. You can inspect the docket 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 preamble 
between 7:30 a.m. and 4 p.m., Monday through Friday, except Federal 
holidays.
    We will consider all comments we receive by the closing date for 
comments. We may change these special conditions based on the comments 
we receive.
    If you want us to acknowledge receipt of your comments on these 
special conditions, include with your comments a self-addressed, 
stamped postcard on which you have written the docket number. We will 
stamp the date on the postcard and mail it back to you.

Background

    The Boeing Company has applied for a type-design change for the 
Boeing 737NG airplanes to use rechargeable lithium batteries and 
rechargeable lithium-battery systems in different applications, 
including the recorder independent power supply (RIPS). Lithium 
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. Large, high-
capacity, rechargeable lithium batteries and rechargeable lithium-
battery systems are a novel or unusual design feature in transport-
category airplanes. The FAA is proposing this special condition to 
require that (1) all characteristics of rechargeable lithium battery 
and rechargeable lithium-battery system installation, that could affect 
safe operation of the Boeing 737NG, are addressed, and (2) appropriate 
instructions for continued airworthiness, which include maintenance 
requirements, are established to ensure the availability of electrical 
power from the batteries when needed.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14 
CFR) 21.101, the Boeing Company must show that the Boeing 737NG 
airplanes, as changed, continue to meet the applicable provisions of 
the regulations incorporated by reference in Type Certificate No. A16WE 
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 regulation incorporated by reference in 
A16WE is 14 CFR 25.1353 at Amendment 25-38.
    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 Boeing Company rechargeable 
lithium batteries and rechargeable lithium-battery systems because of a 
novel or unusual design feature, special conditions are prescribed 
under the provisions of Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Boeing 737NG 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; 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, in 
accordance with Sec.  11.38, and they become part of the type-
certification basis under Sec.  21.101.
    Special conditions are initially applicable to the model for which 
they are issued. Should the applicant apply for a type-design change to 
modify any other model included on the same type certificate, to 
incorporate the same novel or unusual design feature, the special 
conditions would also apply to the other model.

Novel or Unusual Design Features

    The Boeing Company modification to Boeing 737NG airplanes will 
incorporate the following novel or unusual design feature: Rechargeable 
lithium batteries and rechargeable 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, respectively, the FAA issued Sec.  25.1353(c)(5) and (c)(6), 
governing nickel-cadmium battery installations on large, transport-
category airplanes.
    The proposed use of rechargeable lithium batteries and rechargeable 
lithium-battery systems for equipment and systems on the Boeing 737NG 
have 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 rechargeable lithium batteries and rechargeable 
lithium-battery systems that could affect the safety and reliability of 
the Boeing 737NG rechargeable lithium batteries and rechargeable 
lithium-battery system installations.
    At present, commercial aviation has limited experience with the use 
of rechargeable lithium batteries and rechargeable lithium-battery 
systems in aviation applications. However, other users of this 
technology, ranging from wireless telephone manufacturers to the 
electric vehicle industry, have noted safety problems with lithium 
batteries. These problems include overcharging, over-discharging, and 
cell-component flammability.

1. Overcharging

    In general, rechargeable lithium batteries and rechargeable 
lithium-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 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

[[Page 18401]]

metallic lithium. 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 greater amount of liquid electrolytes in large batteries.

2. Over-discharging

    Discharge of some types of rechargeable lithium batteries and 
rechargeable lithium-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 flight crews 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 
rechargeable lithium batteries and rechargeable lithium-battery systems 
use liquid electrolytes that are flammable. Electrolytes can serve as a 
source of fuel for an external fire from a breach of the battery 
container.
    Such problems, experienced by users of rechargeable lithium 
batteries and rechargeable lithium-battery systems, raise concern about 
the use of these batteries in commercial aviation. The intent of these 
proposed special conditions is to establish appropriate airworthiness 
standards for rechargeable lithium-battery and rechargeable lithium-
battery system installations in Boeing 737NG airplanes and to ensure, 
as required by Sec. Sec.  25.1309 and 25.601, that these battery 
installations are not hazardous or unreliable.

Applicability

    As discussed above, these special conditions are applicable to the 
Boeing Company. Should the Boeing Company apply at a later date for a 
type-design change to modify any other model included on Type 
Certificate No. A16WE, 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 
relating to rechargeable lithium batteries and rechargeable lithium-
battery systems installed on Boeing 737NG airplanes. It is not a rule 
of general applicability and affects only the applicant who applied to 
the FAA for approval of these features on the airplane.
    The substance of these special conditions has been subjected to the 
notice and comment period in several prior instances and has been 
derived without substantive change from those previously issued. It is 
unlikely that prior public comment would result in a significant change 
from the substance contained herein. Therefore, because a delay would 
significantly affect the certification of the airplane, which is 
imminent, the FAA has determined that prior public notice and comment 
are unnecessary and impracticable, and good cause exists for adopting 
these special conditions upon issuance. The FAA is requesting comments 
to allow interested persons to submit views that may not have been 
submitted in response to the prior opportunities for comment described 
above.

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

    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 Boeing 737NG airplanes modified by 
Boeing Company to install rechargeable lithium-battery systems on 
Boeing 737NG airplanes. These systems 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-battery installation must preclude 
explosion in the event of those failures.
    (2) Design of the lithium batteries must preclude the occurrence of 
self-sustaining, uncontrolled increases in temperature or pressure.
    (3) No explosive or toxic gases emitted by any lithium battery in 
normal operation, or as the result of any failure of the battery-
charging system, monitoring system, or battery installation which is 
not shown to be extremely remote, may accumulate in hazardous 
quantities within the airplane.
    (4) Installations of lithium batteries must meet the requirements 
of Sec.  25.863(a) through (d).
    (5) No corrosive fluids or gases that may escape from any lithium 
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 
Sec.  25.1309 (b) and applicable regulatory guidance.
    (6) Each lithium-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-battery installations must have--
    (i) A system to automatically control the charging rate of the 
battery, to prevent battery overheating or overcharging, and,
    (ii) 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,
    (iii) 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-battery installation the function of which 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 Sec.  
25.1529 (and Sec.  26.11) must contain maintenance steps to assure that 
the lithium batteries are sufficiently charged at appropriate intervals 
specified by the battery manufacturer. The instructions for continued 
airworthiness must also contain procedures to ensure the integrity of 
lithium batteries in spares storage to prevent the replacement of 
batteries, the function of which 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. Precautions should be included in the instructions for 
continued-airworthiness maintenance instructions to prevent mishandling 
of lithium batteries, which could result in short-circuit or other 
unintentional damage that could result in personal injury or property 
damage.


[[Page 18402]]


    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 there is 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) in the certification basis of the Boeing 737NG. 
These special conditions apply only to rechargeable lithium 
batteries and rechargeable lithium-battery system installations. The 
requirements of Sec.  25.1353(b) remains in effect for batteries and 
battery installations of Boeing 737NG that do not use lithium 
batteries.

    Boeing must show compliance with the requirements of these special 
conditions by test and/or analysis. The aircraft certification office, 
or its designees, will find compliance in coordination with the FAA 
Transport Standards Staff.

    Issued in Renton, Washington, on April 5, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-8218 Filed 4-9-10; 8:45 am]
BILLING CODE 4910-13-P