Source: https://www.federalregister.gov/documents/2010/04/12/2010-8218/special-conditions-modification-to-boeing-model-737-600-700-700c-800-900-and--900er-series-airplanes
Timestamp: 2017-08-19 14:05:41
Document Index: 338593542

Matched Legal Cases: ['art 25', '§\u200921', 'art 34', 'art 36', '§\u200925', '§\u200925', '§\u200925', '§\u200926', '§\u200925', '§\u200925']

Federal Register :: Special Conditions: Modification to Boeing Model 737-600/-700/-700C/-800/-900 and -900ER Series Airplanes: Rechargeable Lithium Batteries and Rechargeable Lithium-Battery Systems
Special Conditions: Modification to Boeing Model 737-600/-700/-700C/-800/-900 and -900ER Series Airplanes: Rechargeable Lithium Batteries and Rechargeable Lithium-Battery Systems
The effective date of these special conditions is April 5, 2010. We must receive your comments by May 27, 2010.
18399-18402 (4 pages)
Docket No. NM426
Special Conditions No. 25-404-SC
https://www.federalregister.gov/d/2010-8218 https://www.federalregister.gov/d/2010-8218
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.
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.
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.
The FAA has determined that notice of, and opportunity for prior public comment on, these special conditions are impracticable because these procedures Start Printed Page 18400would 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.
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.
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 § 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.”
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.
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.
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.
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 Start Printed Page 18401metallic 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.
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.
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 §§ 25.1309 and 25.601, that these battery installations are not hazardous or unreliable.
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.
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.
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.
(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 § 25.1309 (b) and applicable regulatory guidance.
(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 § 25.1529 (and § 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.
Start Printed Page 18402
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.
These special conditions are not intended to replace § 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 § 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.
[FR Doc. 2010-8218 Filed 4-9-10; 8:45 am]