Source: https://www.federalregister.gov/documents/2015/03/03/2015-04366/special-conditions-cessna-aircraft-company-model-650-citation-vii-airplane-as-modified-by-universal
Timestamp: 2017-09-22 14:40:22
Document Index: 442352773

Matched Legal Cases: ['§\u200921', 'art 25', '§\u200921', '§\u200921', 'art 34', 'art 36', 'art 4', 'art 25', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925']

Federal Register :: Special Conditions: Cessna Aircraft Company, Model 650, Citation VII Airplane; As Modified by Universal Avionics Systems Corporation; Installed Rechargeable Lithium Batteries and Battery Systems
Special Conditions: Cessna Aircraft Company, Model 650, Citation VII Airplane; As Modified by Universal Avionics Systems Corporation; Installed Rechargeable Lithium Batteries and Battery Systems
This action is effective on Cessna Aircraft Company on March 3, 2015. We must receive your comments by April 17, 2015.
80 FR 11319
11319-11321 (3 pages)
Docket No. FAA-2015-0441
Special Conditions No. 25-577-SC
FAA-2015-0441
https://www.federalregister.gov/d/2015-04366 https://www.federalregister.gov/d/2015-04366
These special conditions are issued for the Cessna Aircraft Company, Model 650, Citation VII Airplane. This airplane as modified by Universal Avionics Systems Corporation will have a novel or unusual design feature when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. This design feature is for the installation of Universal Avionics InSightTM Electronic Flight Instrument System (EFIS), Engine Interface Units (EIU), UNS-1Fw Wide Area Augmentation System (WAAS) Flight Management System (FMS), and Terrain Awareness and Warning System (TAWS) Class A, which will use rechargeable lithium batteries and 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.
Send comments identified by docket number FAA-2015-0441 using any of the following methods:
Nazih Khaouly, FAA, Airplane and Flightcrew 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.
On January 13, 2014, Universal Avionics Systems Corporation applied for a supplemental type certificate (STC) for the installation of Universal Avionics InSightTM EFIS, EIU, UNS-1Fw WAAS FMS, and TAWS Class A, which will use rechargeable lithium batteries and battery systems. The Cessna, Model 650, Citation VII is a pressurized, two-crew, seven-passenger, low wing transport with two aft mounted turbo-fan engines.
Rechargeable lithium 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 transport category airplanes.
Under the provisions of § 21.101, Universal Avionics Systems Corporation must show that the Cessna, Model 650, Citation VII, as changed, continues to meet the applicable provisions of the regulations listed in Type Certificate No. A9NM or the applicable regulations in effect on the date of application for the change except for earlier amendments as Start Printed Page 11320agreed upon by the FAA. The regulations listed in the type certificate are commonly referred to as the “original type-certification basis.”
In addition, if the regulations listed do not provide adequate standards regarding the change, the applicant must comply with certain regulations in effect on the date of application for the change.
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 Cessna, Model 650, Citation VII airplane because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16.
Special conditions are initially applicable to the model for which they are issued. Should the applicant apply for a supplemental type certificate (STC) to modify any other model included on the same type certificate to incorporate the same or similar novel or unusual design feature, these special conditions would also apply to the other model under § 21.101.
In addition to the applicable airworthiness regulations and special conditions, the Cessna, Model 650, Citation VII 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 Cessna, Model 650, Citation VII will incorporate the following novel or unusual design feature: The installation of a Universal Avionics InSightTM EFIS, EIU, UNS-1Fw WAAS FMS, and TAWS Class A, which will use rechargeable lithium batteries and battery systems.
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, § 25.1353(c)(1) through (c)(4), reworded the CAR requirements.
Increased use of nickel-cadmium batteries in small airplanes resulted in increased incidents of battery fires and failures that led to additional rulemaking affecting large transport category airplanes as well as small airplanes. On September 1, 1977 and March 1, 1978, the FAA issued § 25.1353(c)(5) and (c)(6), respectively, governing nickel-cadmium battery installations on large transport-category airplanes.
The proposed use of rechargeable lithium batteries for equipment and systems 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 that could affect the safety and reliability of the Cessna, Model 650, Citation VII airplane lithium battery installations.
At present, there is limited experience with the use of rechargeable lithium batteries and battery systems 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 rechargeable lithium batteries. These problems include overcharging, over-discharging, and flammability of cell components.
In general, lithium batteries 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 condition 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 metallic lithium. The 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 higher amount of electrolyte in large batteries.
Discharge of some types of lithium battery cells 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—a problem shared with nickel-cadmium batteries.
These problems experienced by users of lithium batteries raise concern about the use of these batteries in commercial aviation. The intent of the special conditions are to establish appropriate airworthiness standards for lithium battery installations in the Cessna, Model 650, Citation VII airplane and to ensure, as required by §§ 25.1309 and 25.601, that these batteries are not hazardous or unreliable.
As discussed above, these special conditions are applicable to the Cessna, Model 650, Citation VII airplane. Should Universal Avionics Systems Corporation apply at a later date for a supplemental type certificate to modify any other model included on Type Certificate No. A9NM to incorporate the same or similar novel or unusual design feature, these special conditions would apply to that model as well.
This action affects only a certain novel or unusual design feature on one airplane model. It is not a rule of general applicability and affects only the applicant who applied to the FAA for approval of this feature on the airplane.
End List of Subjects Start Printed Page 11321
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 Cessna, Model 650, Citation VII airplanes modified by Universal Avionics Systems Corporation.
These special conditions require that (1) all characteristics of the rechargeable lithium batteries and battery installation that could affect safe operation of the Cessna, Model 650, Citation VII airplanes are addressed; and (2) appropriate instructions for continued airworthiness, which include maintenance requirements, are established to ensure the availability of electrical power, when needed, from the batteries.
In lieu of the requirements of Title 14, Code of Federal Regulations (14 CFR) 25.1353(b)(1) through (b)(4) at amendment 25-123, all rechargeable lithium batteries and battery systems on Cessna, Model 650, Citation VII airplanes, modified by Universal Avionics Systems Corporation, 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 rechargeable lithium battery installation must preclude explosion in the event of those failures.
2. Design of the rechargeable lithium batteries must preclude the occurrence of self-sustaining, uncontrolled increases in temperature or pressure.
3. No explosive or toxic gases emitted by any rechargeable 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 rechargeable lithium batteries must meet the requirements of § 25.863(a) through (d).
5. No corrosive fluids or gases that may escape from any rechargeable 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.
6. Each rechargeable 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. Rechargeable lithium battery installations must have a system to control the charging rate of the battery automatically, so as to prevent battery overheating or overcharging, and:
a. 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,
b. 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 rechargeable 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 must contain maintenance requirements to assure that the battery is sufficiently charged at appropriate intervals specified by the battery manufacturer and the equipment manufacturer that contain the rechargeable lithium battery or rechargeable lithium battery system. This is required to ensure that lithium rechargeable batteries and lithium rechargeable battery systems will not degrade below specified ampere-hour levels sufficient to power the airplane systems for intended applications. The instructions for continued airworthiness must also contain procedures for the maintenance of batteries in spares storage to prevent the replacement of batteries with batteries that have experienced degraded charge retention ability or other damage due to prolonged storage at a low state of charge. Replacement batteries must be of the same manufacturer and part number as approved by the FAA. Precautions should be included in the instructions for continued airworthiness maintenance instructions to prevent mishandling of the rechargeable lithium battery and rechargeable lithium battery systems, which could result in short-circuit or other unintentional impact damage caused by dropping or other destructive means that could result in personal injury or property damage.
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 the battery experiences 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 § 25.1353(b) in the certification basis of Cessna, Model 650, Citation VII airplanes. These special conditions apply only to rechargeable lithium batteries, lithium battery systems, and their installations. The requirements of § 25.1353(b) remain in effect for batteries and battery installations on Cessna, Model 650, Citation VII airplanes that do not use lithium batteries.
Issued in Renton, Washington, on February 23, 2015.
[FR Doc. 2015-04366 Filed 3-2-15; 8:45 am]