[Federal Register: June 4, 2009 (Volume 74, Number 106)]
[Proposed Rules]
[Page 26818-26820]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr04jn09-24]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. CE296; Notice No. 23-09-02SC]
Special Conditions: Cessna Aircraft Company, Model 525C (CJ4);
Lithium Ion Battery Installation
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
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SUMMARY: This action proposes special conditions for the Cessna
Aircraft Company, model 525C (CJ4) airplane. This airplane will have a
novel or unusual design feature associated with the installation of
lithium ion (Li-ion) batteries. Cessna Aircraft Company proposes to use
a lithium-ion main battery on the new model 525C (CJ4) commuter
category airplane for main battery applications, and is also
considering the use of this technology in several other auxiliary
battery applications in this airplane. This type of battery possesses
certain failure, operational characteristics, and maintenance
requirements that differ significantly from that of the nickel cadmium
and lead acid rechargeable batteries currently approved in other
normal, utility, acrobatic, and commuter category airplanes. The
applicable airworthiness regulations do not contain adequate or
appropriate safety standards for this design feature. 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.
DATES: We must receive your comments by July 6, 2009.
ADDRESSES: Mail two copies of your comments to Federal Aviation
Administration, Regional Counsel, ACE-7, Attention: Rules Docket Clerk,
Docket No. CE296, Room 506, 901 Locust, Kansas City, Missouri 64106.
You may deliver two copies to the Small Airplane Directorate at the
above address. Mark your comments: Docket No. CE296. You may inspect
comments in the Rules Docket weekdays, except Federal holidays, between
7:30 a.m. and 4 p.m.
FOR FURTHER INFORMATION CONTACT: Ervin Dvorak, Aerospace Engineer,
Standards Office (ACE-111), Small Airplane Directorate, Aircraft
Certification Service, Federal Aviation Administration, 901 Locust,
Room 301, Kansas City, Missouri 64106; telephone (816) 329-4123.
SUPPLEMENTARY INFORMATION:
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
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 special conditions. You may 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 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
these special conditions based on the 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 August 9, 2006, Cessna Aircraft Company applied for an amendment
to Type Certificate Number A1WI to include the new model 525C (CJ4).
The model 525C (CJ4), which is a derivative of the model 525B (CJ3)
currently approved under Type Certificate Number A1WI, is a commuter
category, low-winged monoplane with ''T'' tailed vertical and
horizontal stabilizers, retractable tricycle type landing gear and twin
turbofan engines mounted on the aircraft fuselage. The maximum takeoff
weight is 16,950 pounds, the VMO/MMO is 305 KIAS/M 0.77 and maximum
altitude is 45,000 feet. Cessna Aircraft Company proposes to utilize
lithium Ion (Li-ion) batteries for main battery applications, and is
considering the use of this technology in several other auxiliary
battery applications in this airplane.
Type Certification Basis
Under the provisions of 14 CFR part 21, Sec. 21.101, Cessna
Aircraft Company must show that the model 525C (CJ4)
[[Page 26819]]
meets the applicable provisions of the requirements incorporated by
reference in Type Certificate No. A1W1 or 14 CFR part 23, as amended by
Amendments 23-1 through 23-57 thereto. The regulations incorporated by
reference in the type certificate are commonly referred to as the
original type certificate basis.
In addition, the certification basis includes certain special
conditions, and exemptions that are not relevant to these proposed
special conditions.
In addition to the applicable airworthiness regulations and special
conditions, the model 525C (CJ4) 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 Sec. 611 of Public Law 92-574,
the ``Noise Control Act of 1972.''
If the Administrator finds that the applicable airworthiness
regulations (i.e., 14 CFR part 23) do not contain adequate or
appropriate safety standards for the model 525C (CJ4) because of a
novel or unusual design feature, special conditions are prescribed
under the provisions of Sec. 21.16.
The FAA issues special conditions, as defined in Sec. 11.19, under
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 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 Sec. 21.101.
Novel or Unusual Design Features
Cessna Aircraft Company, model 525C (CJ4) will incorporate the
following novel or unusual design features:
Cessna Aircraft Company proposes to use lithium ion (Li-ion)
batteries for main battery applications, and is considering the use of
this technology in several other auxiliary battery applications on the
Cessna Aircraft Company, model 525C (CJ4) airplane. This type of
battery possesses certain failure and operational characteristics, and
maintenance requirements that differ significantly from that of the
nickel cadmium (Ni-Cd) and lead acid rechargeable batteries currently
approved for installation in small airplanes. Current regulations in 14
CFR part 23 do not address installation of Li-ion batteries. This
special condition is being proposed to require that all characteristics
of the Li-ion battery and its installation that could affect safe
operation of the Cessna Aircraft Company, model 525C (CJ4) airplane are
addressed, along with establishing that appropriate maintenance
requirements must be provided to ensure electrical power is available
from the batteries when needed.
Discussion
The applicable part 21 and part 23 airworthiness regulations
governing the installation of batteries in general aviation airplanes,
including part 23, Sec. 23.1353 were derived from Civil Air
Regulations (CAR 3) as part of the recodification that established
Federal Aviation Regulation 14 CFR part 23. The battery requirements,
which were identified as 14 CFR part 23, Sec. 23.1353, were basically
a rewording of the CAR requirements that did not add any substantive
technical requirements. An increase in incidents involving battery
fires and failures that accompanied the increased use of Nickel-Cadmium
(Ni-Cd) batteries in airplanes resulted in rulemaking activities on the
battery requirements for business jet and commuter category airplanes.
These regulations were incorporated into 14 CFR part 23, Sec.
23.1353(f) and (g), which apply only to Ni-Cd battery installations.
The proposed use of Li-ion batteries on the Cessna Aircraft
Company, model 525C (CJ4) airplane has prompted the FAA to review the
adequacy of the existing battery regulations with respect to that
chemistry. As the result of this review, the FAA has determined that
the existing regulations do not adequately address several failure,
operational, and maintenance characteristics of Li-ion batteries that
could affect safety of the battery installation and the reliability of
the Cessna Aircraft Company, model 525C (CJ4) airplane electrical power
supply.
Li-ion batteries in general are significantly more susceptible to
internal failures that can result in self-sustaining increases in
temperature and pressure (i.e., thermal runaway) than their Ni-Cd and
lead-acid counterparts. This is especially true for overcharging a Li-
ion, which will likely result in explosion, fire, or both. Certain
types of Li-ion batteries pose a potential safety problem because of
the instability and flammability of the organic electrolyte employed by
the cells of those batteries. The severity of thermal runaway increases
with increasing battery capacity due to the higher amount of
electrolyte in large batteries.
Discharge of some versions of the Li-Poly cell beyond a certain
voltage below 3.0 volts will subsequently no longer accept a charge.
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 Ni-Cd batteries.
Unlike Ni-Cd and lead-acid cells, some types of Li-ion cells employ
electrolytes that are known to be flammable. This material can serve as
a source of fuel for an external fire in the event of a breach of the
cell container.
The intent of the proposed special condition is to establish
appropriate airworthiness standards for Li-ion battery installations in
the Cessna Aircraft Company, model 525C (CJ4) airplane, and to ensure,
as required by 14 CFR part 23, Sec. 23.601, that these battery
installations do not possess hazardous or unreliable design
characteristics. The proposed special condition adopts the following
requirements as a means of addressing these concerns:
Inclusion of those sections of 14 CFR part 23, Sec.
23.1353 that are applicable to Li-ion batteries.
Inclusion of the flammable fluid fire protection
requirements of 14 CFR part 23, Sec. 23.863. In the past, this rule
was not applied to the batteries of business jet or commuter category
airplanes since the electrolytes utilized in lead-acid and Ni-CD
batteries are not considered to be flammable.
Addition of new requirements to address the potential
hazards of overcharging and overdischarging that are unique to Li-ion
battery designs.
Addition of maintenance requirements to ensure that batteries used
as spares are maintained in an appropriate state of charge (SOC).
Applicability
As discussed above, these special conditions are applicable to the
Cessna model 525C (CJ4). Should Cessna Aircraft Company apply at a
later date for a change to the type certificate to include another
model incorporating 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
on one model of airplane. It is not a rule of general applicability.
List of Subjects in 14 CFR Part 23
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
Citation
The authority citation for these special conditions is as follows:
[[Page 26820]]
Authority: 49 U.S.C. 106(g), 40113, and 44701; 14 CFR 21.16 and
21.17; 14 CFR 11.38 and 11.19.
The Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Cessna Aircraft Company, model 525C (CJ4) airplanes.
Cessna Aircraft Company, Model 525C (CJ4) Lithium Ion Battery
Installation
In lieu of the requirements of 14 CFR part 23, Sec. 23.1353(a)
through (e), lithium ion batteries and battery installations on the
Cessna Aircraft Company, model 525C (CJ4) airplane must be designed and
installed as follows:
(1) Safe cell temperatures and pressures must be maintained during
any probable charging or discharging condition, or during any failure
of the charging or battery monitoring system not shown to be extremely
remote. The Li-ion battery installation must be designed to preclude
explosion or fire in the event of those failures.
(2) Li-ion batteries must be designed to preclude the occurrence of
self-sustaining, uncontrolled increases in temperature or pressure.
(3) No explosive or toxic gasses emitted by any Li-ion battery in
normal operation or as the result of any failure of the battery
charging or monitoring system, or battery installation not shown to be
extremely remote, may accumulate in hazardous quantities within the
airplane.
(4) Li-ion batteries that contain flammable fluids must comply with
the flammable fluid fire protection requirements of 14 CFR part 23,
Sec. 23.863(a) through (d).
(5) No corrosive fluids or gasses that may escape from any Li-ion
battery may damage surrounding airplane structure or adjacent essential
equipment.
(6) Each Li-ion battery installation must have provisions to
prevent any hazardous effect on structure or essential systems that may
be caused by the maximum amount of heat the battery can generate during
a short circuit of the battery or of its individual cells.
(7) Li-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 Li-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 capacity and SOC of the batteries have
fallen below levels considered acceptable for dispatch of the airplane.
(9) The Instructions for Continued Airworthiness (ICAW) must
contain recommended manufacturers maintenance and inspection
requirements to ensure that batteries, including single cells, meet a
safety function level essential to the aircraft's continued
airworthiness.
(i) The ICAW must contain operating instructions and equipment
limitations in an installation maintenance manual.
(ii) The ICAW must contain installation procedures and limitation
in a maintenance manual, sufficient to ensure that cells or batteries,
when installed according to the installation procedures, still meet
safety functional levels, essential to the aircraft's continued
airworthiness. The limitation must identify any unique aspects of the
installation.
(iii) The ICAW must contain corrective maintenance procedures to
functionally check battery capacity at manufacturers recommended
inspection intervals.
(iv) The ICAW must contain scheduled servicing information to
replace batteries at manufacturers recommended replacement time.
(v) The ICAW must contain maintenance inspection requirements to
visually check for a battery and/or charger degradation.
(10) Batteries in a rotating stock (spares) that have experienced
degraded charge retention capability or other damage due to prolonged
storage must be functionally checked at manufacturers recommended
inspection intervals.
(11) System Safety Assessment process should address the software
and complex hardware levels for the sensing, monitoring and warning
systems, if these systems contain complex devices. The functional
hazard assessment (FHA) for the system is required based on the
intended functions described. The criticality of the specific functions
will be determined by the safety assessment process for compliance with
14 CFR part 23, Sec. 23.1309, and Advisory Circular 23.1309-1D
contains acceptable means for accomplishing this requirement. For
determining the failure condition, the criticality of a function will
include the mitigating factors. The failure conditions must address the
loss of function and improper operations.
These special conditions are not intended to replace 14 CFR part
23, Sec. 23.1353 in the certification basis of the Cessna Aircraft
Company, model 525C (CJ4) airplanes. The proposed special conditions
would apply only to Li-ion batteries and battery installations. The
battery requirements of 14 CFR part 23, Sec. 23.1353 would remain in
effect for batteries and battery installations on the Cessna Aircraft
Company, model 525C (CJ4) airplane that do not use Li-ion chemistry.
Issued in Kansas City, Missouri on May 27, 2009.
John Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E9-12994 Filed 6-3-09; 8:45 am]
BILLING CODE 4910-13-P