[Federal Register Volume 81, Number 94 (Monday, May 16, 2016)]
[Rules and Regulations]
[Pages 30164-30166]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-11502]

[[Page 30164]]



Federal Aviation Administration

14 CFR Part 23

[Docket No. FAA-2016-6567; Special Conditions No. 23-274-SC]

Special Conditions: Cessna Aircraft Company, Models 208 and 208B, 
Caravan Airplanes; As Modified by Peregrine; Installation of 
Rechargeable Lithium Battery

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.


SUMMARY: These special conditions are issued for the Cessna Aircraft 
Company, Models 208 and 208B Caravan airplanes. This airplane, as 
modified by Peregrine, will have a novel or unusual design feature 
associated with the use of a replacement option of a lithium battery 
instead of nickel-cadmium (Ni-Cd) and lead-acid rechargeable batteries. 
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.

DATES: The effective date of these special conditions is May 16, 2016. 
We must receive your comments by June 15, 2016.

ADDRESSES: Send comments identified by docket number FAA-2016-6567 
using any of the following methods:
     Federal eRegulations Portal: Go to http://www.regulations.gov and follow the online instructions for sending your 
comments electronically.
     Mail: Send comments to Docket Operations, M-30, U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room 
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery of Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: The FAA will post all comments it receives, without 
change, to http://regulations.gov, including any personal information 
the commenter provides. Using the search function of the docket Web 
site, anyone can find and read the electronic form of all comments 
received into any FAA docket, including the name of the individual 
sending the comment (or signing the comment for an association, 
business, labor union, etc.). DOT's complete Privacy Act Statement can 
be found in the Federal Register published on April 11, 2000 (65 FR 
19477-19478), as well as at http://DocketsInfo.dot.gov.
    Docket: Background documents or comments received may be read at 
http://www.regulations.gov at any time. Follow the online instructions 
for accessing the docket or go to the Docket Operations in Room W12-140 
of the West Building Ground Floor at 1200 New Jersey Avenue SE., 
Washington, DC, between 9 a.m., and 5 p.m., Monday through Friday, 
except Federal holidays.

Administration, Small Airplane Directorate, Aircraft Certification 
Service, ACE-114, 901 Locust, Room 301, Kansas City, MO 64106; 
telephone (816) 329-4108, facsimile (816) 329-4090.

    The FAA has determined, in accordance with 5 U.S.C. 553(b)(3)(B) 
and 553(d)(3), that notice and opportunity for prior public comment 
hereon are unnecessary because the substance of this special condition 
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.

       Special  condition  number             Company/airplane model
23-269-SC \1\..........................  Honda Aircraft Company Model HA-
23-236-SC \2\..........................  Cessna Aircraft Company Model
                                          525C (CJ4).
23-249-SC \3\..........................  Cessna Aircraft Company Model
                                          525 Citation.
\1\ http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSC.nsf/0/673E1A183F208FF186257EC90042DD79?OpenDocument&Highlight=lithium%20ion%20battery%20installation.
\2\ http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSC.nsf/0/83608DAA4B3E5D7A8625761D004EDE7B?OpenDocument&Highlight=lithium%20ion%20battery%20installation.
\3\ http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSC.nsf/0/BBFDE3920E2AFB1D862577700046E311?OpenDocument&Highlight=lithium%20ion%20battery%20installation.

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 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.


    On March 25, 2015, Peregrine applied for a supplemental type 
certificate (STC) to install a rechargeable lithium battery on the 
Cessna Models 208 and 208B Caravan airplanes. Both the 208 and 208B are 
normal category airplanes, powered by a single-turbine engine that 
drives an aircraft propeller, with passenger seating up to eleven (11) 
and a maximum takeoff weight of 8,000 and 8,750 pounds respectively.
    The current regulatory requirements for part 23 airplanes do not 
contain adequate requirements for the application of rechargeable 
lithium batteries in airborne applications. This type of battery 
possesses certain failure and operational characteristics with 
maintenance requirements that differ significantly from that of the Ni-
Cd and lead-acid rechargeable batteries currently approved in other 
normal, utility, acrobatic, and commuter category airplanes. Therefore, 
the FAA is proposing this special condition to address (1) all 
characteristics of the rechargeable lithium batteries and their 
installation that could affect safe operation of the modified 208 and 
208B airplanes, and (2) appropriate Instructions for Continued 
Airworthiness (ICAW) that include maintenance requirements to ensure 
the availability of electrical power from the batteries when needed.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (CFR) 
21.101, Peregrine must show that the 208 and 208B airplanes, as 
changed, continue to meet the applicable provisions of the regulations 
incorporated by reference in Type Certificate Data Sheet No. A37CE, or 
the applicable regulations in effect on the date of application for the 
    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 208 and 208B airplanes because of 
a novel or unusual design feature, special conditions are prescribed 
under the provisions of Sec.  21.16.

[[Page 30165]]

    In addition to the applicable airworthiness regulations and special 
conditions, the 208 and 208B 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 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 models for which 
they are issued. Should the applicant apply for an STC to modify any 
other model included on the same type certificate to incorporate the 
same novel or unusual design feature, these special conditions would 
also apply to the other model under Sec.  21.101.

Novel or Unusual Design Features

    The Cessna Models 208 and 208B airplanes will incorporate the 
following novel or unusual design features:
    The installation of a rechargeable lithium battery as a main or 
engine start aircraft battery.


    The applicable part 23 airworthiness regulations governing the 
installation of batteries in general aviation airplanes, including 
Sec.  23.1353, were derived from Civil Air Regulations (CAR) 3 as part 
of the recodification that established 14 CFR part 23. The battery 
requirements, which are identified in Sec.  23.1353, were 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 Ni-Cd batteries in 
aircraft resulted in rulemaking activities on the battery requirements 
for transport category airplanes. These regulations were incorporated 
into Sec.  23.1353(f) and (g), which apply only to Ni-Cd battery 
    The introduction of lithium batteries into aircraft raises some 
concern about associated battery or cell monitoring systems and the 
impact to the electrical system when monitoring components fail. 
Associated battery or cell monitoring systems (e.g., temperature, state 
of charge, etc.) should be evaluated with respect the expected extremes 
in the aircraft operating environment.
    Lithium batteries typically have different electrical impedance 
characteristics than Ni-Cd or lead-acid batteries. Peregrine needs to 
evaluate other components of the aircraft electrical system with 
respect to these characteristics.
    Presently, there is limited experience with use of rechargeable 
lithium batteries and rechargeable lithium battery systems in 
applications involving commercial aviation. However, other users of 
this technology, ranging from personal computers, wireless telephone 
manufacturers to the electric vehicle industry, have noted safety 
problems with rechargeable lithium batteries. These problems include 
overcharging, over-discharging, flammability of cell components, cell 
internal defects, and during exposure to extreme temperatures that are 
described in the following paragraphs.
    1. Overcharging: In general, rechargeable lithium batteries are 
significantly more susceptible to internal failures that can result in 
self-sustaining increases in temperature and pressure (e.g., thermal 
runaway) than their Ni-Cd 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 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.
    2. Over-discharging: Discharge of some types of rechargeable 
lithium battery cells beyond the manufacturer's recommended 
specification 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 Ni-Cd batteries. In 
addition, over-discharging has the potential to lead to an unsafe 
condition (creation of dendrites that could result in internal short 
circuit during the recharging cycle).
    3. Flammability of Cell Components: Unlike Ni-Cd and lead-acid 
batteries, some types of rechargeable lithium 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 
    4. Cell Internal Defects: The rechargeable lithium batteries and 
rechargeable battery systems have a history of undetected cell internal 
defects. These defects may or may not be detected during normal 
operational evaluation, test and validation. This may lead to an unsafe 
condition during in service operation.
    5. Extreme Temperatures: Exposure to an extreme temperature 
environment has the potential to create major hazards. Care must be 
taken to ensure that the lithium battery remains within the 
manufacturer's recommended specification.
    These problems experienced by users of lithium batteries raise 
concern about the use of lithium batteries in aviation. The intent of 
the proposed special condition is to establish appropriate 
airworthiness standards for lithium battery installations in the 208 
and 208B airplanes and to ensure, as required by Sec. Sec.  23.1309 and 
23.601, that these battery installations are not hazardous or 


    The special conditions are applicable to the 208 and 208B 
airplanes. Should Peregrine apply at a later date for an STC to modify 
any other model included on Type Certificate No. A37CE 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 
on the 208 and 208B 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.
    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 subject contained herein. Therefore, notice and opportunity 
for prior public comment hereon are unnecessary and the FAA finds good 
cause, in accordance with 5 U.S.C. 553(b)(3)(B) and 553(d)(3), making 
these special conditions effective 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 comment 
described above.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.


The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113 and 44701; 14 CFR 21.16 and 
21.101; and 14 CFR 11.38 and 11.19.

[[Page 30166]]

The Special Conditions

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 Aircraft Company, 208 and 208B 
Caravan airplanes modified by Peregrine.

1. Installation of Lithium Battery

    The FAA states in this Notice that the following special conditions 
be applied to lithium battery installations on the 208 and 208B 
airplanes in lieu of the requirements Sec.  23.1353(a)(b)(c)(d)(e), 
amendment 49.
    Lithium battery installations on the 208 and 208B airplanes must be 
designed and installed as follows:
    a. 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 lithium battery installation must be designed to preclude 
explosion or fire in the event of those failures.
    b. Lithium batteries must be designed to preclude the occurrence of 
self-sustaining, uncontrolled increases in temperature or pressure.
    c. No explosive or toxic gasses emitted by any lithium 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 
    d. Lithium batteries that contain flammable fluids must comply with 
the flammable fluid fire protection requirements of 14 CFR 23.863(a) 
through (d).
    e. No corrosive fluids or gases that may escape from any lithium 
battery may damage airplane structure or essential equipment.
    f. Each lithium 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.
    g. Lithium battery installations must have--
    (1) A system to control the charging rate of the battery 
automatically to prevent battery overheating or overcharging, or
    (2) 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,
    (3) 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.
    h. Any lithium battery installation functionally 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 state of charge of the batteries 
have fallen below levels considered acceptable for dispatch of the 
    i. The ICAW must contain recommended manufacturer's maintenance and 
inspection requirements to ensure that batteries, including single 
cells, meet a functionally safe level essential to the aircraft's 
continued airworthiness.
    (1) The ICAW must contain operating instructions and equipment 
limitations in an installation maintenance manual.
    (2) The ICAW must contain installation procedures and limitations 
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 limitations must identify any unique aspects of the 
    (3) The ICAW must contain corrective maintenance procedures to 
check battery capacity at manufacturer's recommended inspection 
    (4) The ICAW must contain scheduled servicing information to 
replace batteries at manufacturer's recommended replacement time.
    (5) The ICAW must contain maintenance and inspection requirements 
how to check visually for battery and charger degradation.
    j. Batteries in a rotating stock (spares) that have degraded charge 
retention capability or other damage due to prolonged storage must be 
checked at manufacturer's recommended inspection intervals.
    k. If the lithium battery application contains software and/or 
complex hardware, in accordance with AC 20-115 \1\ and AC 20-152,\2\ 
they should be developed to the standards of DO-178 for software and 
DO-254 for complex hardware.

    \1\ http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/E35FBC0060E2159186257BBE00719FB3?OpenDocument&Highlight=ac%2020-115b.
    \2\ http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/6D4AE0BF1BDE3579862570360055D119?OpenDocument&Highlight=ac%2020-152.

    Compliance with the requirements of this Special Condition must be 
shown by test or analysis, with the concurrence of the Wichita Aircraft 
Certification Office.

    Issued in Kansas City, Missouri on May 9, 2016.
Pat Mullen,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
[FR Doc. 2016-11502 Filed 5-13-16; 8:45 am]