[Federal Register: December 2, 2008 (Volume 73, Number 232)]
[Proposed Rules]
[Page 73195-73197]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02de08-16]
========================================================================
Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
========================================================================
[[Page 73195]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. CE291; Notice No. 23-08-05-SC]
Special Conditions: Spectrum Aeronautical, LLC Model 40; Lithium
Polymer Battery Installation
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
-----------------------------------------------------------------------
SUMMARY: This action proposes special conditions for the Spectrum
Aeronautical, LLC Model 40 (S-40) airplane. This airplane will have a
novel or unusual design feature associated with the installation of
lithium polymer (Li-Poly) batteries for emergency, main, and auxiliary
power unit (APU) applications. 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 January 2, 2009.
ADDRESSES: You must mail two copies of your comments to Federal
Aviation Administration, Regional Counsel, ACE-7, Attention: Rules
Docket Clerk, Docket No. CE291, Room 506, 901 Locust, Kansas City,
Missouri 64106. You may deliver two copies to the Small Airplane
Directorate at the above address. You must mark your comments: Docket
No. CE291. 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: Jim Brady, 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) 329-4132.
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 November 21, 2007, Spectrum Aeronautical, LLC applied for a type
certificate for their new model 40 airplane. The model 40 (S-40)
airplane, is a 2+9 (pilots + passengers) conventionally configured low
wing normal category twin-engine jet airplane manufactured primarily
from advanced carbon fiber composite materials. The model S-40 is
designed to be certified for a single pilot operation for day, night,
VFR, IFR and flight into known icing operations at altitudes up to
45,000 feet. The company will show compliance with Reduced Vertical
Separation Minimums (RVSM) requirements. Spectrum proposes to utilize
lithium polymer (Li-Poly) batteries for emergency, main, and auxiliary
power unit (APU) on the model S-40 airplane.
Type Certification Basis
Under the provisions of 14 CFR part 21, Sec. 21.17, Spectrum
Aeronautical, LLC must show that the model S-40 meets the applicable
provisions of part 23, as amended by Amendments 23-1 through 23-57
thereto.
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 S-40 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 S-40 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. 21.17(a)(2).
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
The Spectrum S-40 will incorporate the following novel or unusual
design features: Spectrum proposes to utilize lithium polymer (Li-Poly)
batteries for emergency, main, and auxiliary power unit (APU) on the
Spectrum S-40 airplane model. 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
[[Page 73196]]
installation of Li-Poly batteries. This special condition is being
proposed to require that all characteristics of the Li-Poly battery and
its installation that could affect safe operation of the Spectrum S-40
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-Poly batteries on the Spectrum model S-40
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-Poly batteries that could affect safety of the
battery installation and the reliability of the Spectrum model S-40
airplane electrical power supply.
Li-Poly 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-
Poly, which will likely result in explosion, fire, or both. Certain
types of Li-Poly 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-Poly 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-Poly battery installations
in the Spectrum model 40 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-Poly 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-Poly
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
Spectrum model S-40. Should Spectrum Aeronautical, LLC 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.
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
The Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Spectrum Aeronautical, LLC model S-40 airplanes.
Spectrum Aeronautical, LLC Model 40 Lithium Polymer Battery
Installation
In lieu of the requirements of 14 CFR part 23, Sec. 23.1353 (a)
through (e), lithium polymer batteries and battery installations on the
Spectrum S-40 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-Poly battery installation must be designed to preclude
explosion or fire in the event of those failures.
(2) Li-Poly 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-Poly 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-Poly 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-Poly
battery may damage surrounding airplane structure or adjacent essential
equipment.
(6) Each Li-Poly 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-Poly 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,
[[Page 73197]]
(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-Poly 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 23.1309-1C
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.
It should be noted that these special conditions are not intended
to replace 14 CFR part 23, Sec. 23.1353 in the certification basis of
the Spectrum model S-40 airplanes. The proposed special conditions
would apply only to Li-Poly 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 Spectrum airplane
that do not utilize Li-Poly chemistry.
Issued in Kansas City, Missouri on November 20, 2008.
John Colomu,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-28491 Filed 12-1-08; 8:45 am]
BILLING CODE 4910-13-P