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 manufacturers to the electric vehicle industry, have noted safety problems with lithium ion batteries. These problems include overcharging, overdischarging, and flammability of cell components. 1. Overcharging

In general, lithium ion batteries are significantly more susceptible to internal failures that can result in selfsustaining increases in temperature and pressure (i.e., thermal runaway) than their nickelcadmium or leadacid counterparts. This is especially true for overcharging that 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 selfsustaining 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. OverDischarging

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 flight crews as a means of checking battery statusa problem shared with nickelcadmium batteries.

3. Flammability of Cell Components

Unlike nickelcadmium and leadacid batteries, some types of lithium ion batteries 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.

These problems experienced by users of lithium ion batteries raise concern about the use of these batteries in commercial aviation. Accordingly, the proposed use of lithium ion batteries in a satellite communication system on Boeing Model 767200, 300, and 300F series airplanes has prompted the FAA to review the adequacy of existing regulations in 14 CFR 25. Our review indicates that the existing regulations do not adequately address several failure, operational, and maintenance characteristics of lithium ion batteries
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that could affect the safety and reliability of lithium ion battery installations.

The intent of these special conditions is to establish appropriate airworthiness standards for lithium ion batteries in Boeing Model 767 200, 300, and 300F series airplanes modified by ABX Air Inc. and to ensure, as required by 14 CFR 25.601, that these battery installations are not hazardous or unreliable. Accordingly, these special conditions include the following requirements:

In the past, this regulation was not applied to batteries of transport category airplanes, since the electrolytes used in leadacid and nickelcadmium batteries are not flammable.

Type Certification Basis

Under the provisions of 14 CFR 21.101, ABX Air, Inc. must show that the Boeing Model 767200, 300 and 300F series airplanes, as changed, continue to meet the applicable provisions of the regulations incorporated by reference in Type Certificate No. A1NM 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 certification basis for Boeing Model 767200, 300, and 300F series airplanes includes applicable sections of 14 CFR part 25, effective July 30, 1982, as amended by Amendments 251 through 2545, except for portions of Amendment 25.38. In addition, the certification basis includes certain special conditions, exemptions, equivalent levels of safety, or later amended sections of the applicable part 25 that are not relevant to these special conditions.

If the Administrator finds that the applicable airworthiness regulations (i.e., part 25, as amended) do not contain adequate or appropriate safety standards for Boeing Model 767200, 300, and 300F series airplanes 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 Model 767200, 300, and 300F series 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, under 14 CFR 11.38, and they become part of the type certification basis in accordance with Sec. 21.101.

Special conditions are initially applicable to the models for which they are issued. Should ABX Air, Inc. apply for a supplemental type certificate to modify any other model included on Type Certificate No. A1NM to incorporate the same or similar novel or unusual design feature, these special conditions would also apply to the other model. Novel or Unusual Design Features
The Boeing Model 767200, 300, and 300F series airplanesas modified by ABX Air Inc. to include a satellite communication system which uses lithium ion battery technologywill incorporate a novel or unusual design feature. Because of rapid improvements in airplane technology, 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.

The satellite communication system will include a lithium ion battery installation. 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 nickelcadmium and leadacid 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 satellite communication system are addressed, and (2) appropriate maintenance requirements are established to ensure that electrical power is available from the batteries when it is needed. Applicability
As discussed above, these special conditions are applicable to the Boeing Model 767200, 300, and 300F series airplanes as modified by ABX Air Inc. Should ABX Air, Inc. apply at a later date for a supplemental type certificate to modify any other model included on Type Certificate No. A1NM to incorporate the same novel or unusual design feature, these special conditions would apply to that model as well.
Conclusion
This action affects only certain novel or unusual design features of the Boeing Model 767200, 300, and 300F series airplanes as modified by ABX Air Inc. It is not a rule of general applicability and affects only the applicant which 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. For this reason and 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 that 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 comments 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
The FAA proposes the following special conditions as part of the type certification basis for Boeing Model 767200, 300, and 300F series airplanes modified by ABX Air Inc. in lieu of the requirements of 14 CFR 25.1353(c)(1) through (c)(4), Amendment 25113.

Lithium ion batteries and battery installations on Boeing 767200, 300, and 300F series airplanes must be designed and installed as follows:
(1) Safe cell temperatures and pressures must be maintained during [[Page 7205]]
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 selfsustaining, 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 which is 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 overtemperature warning system with a means for automatically disconnecting the battery from its charging source in the event of an overtemperature 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 stateofcharge 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 to assure that the lithium ion battery is sufficiently charged at appropriate intervals specified by the battery manufacturer to ensure that batteries whose function is required for safe operation of the airplane will not degrade below specified amperehour levels sufficient to power the electronic flight bag (EFB) applications that are required for continued safe flight and landing. 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. Precautions should be included in the Instructions for Continued Airworthiness maintenance instructions to prevent mishandling of the lithium ion battery which could result in shortcircuit or other unintentional damage that could result in personal injury or property damage.

Note 1: The term, ``sufficiently charged'' means the charge that is applied to rechargeable lithium ion batteries, which diminishes during the life of batteries with respect to the retentive capacity of the batteries to deliver available powerwhere capacity is the total quantity of electricity of a cell or battery, expressed in amperehours. Battery life is influenced by its internal chemical reaction and by other factors, such as temperature, shock, the number of recharges, etc.

Note 2: These special conditions are not intended to replace 14 CFR 25.1353(c), Amendment 25113 in the certification basis of the ABX, Air Inc supplemental type certificate. These special conditions apply only to lithium ion batteries and their installations. The requirements of 14 CFR 25.1353(c), Amendment 25113 remain in effect for batteries and battery installations on the ABX Air supplemental type certificate that do not use lithium ion batteries.
Compliance with the requirements of this Special Condition must be shown by test or analysis, with the concurrence of the Chicago Aircraft Certification Office.

Issued in Renton, Washington, on January 25, 2008. Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. E82224 Filed 2608; 8:45 am]
BILLING CODE 491013P

FOR FURTHER INFORMATION CONTACT Nazih Khaouly, FAA, Airplane and Flight Crew Interface, ANM111, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue, SW., Renton, Washington 980573356; telephone (425) 2272432; facsimile (425) 227 1149.