[Federal Register Volume 84, Number 196 (Wednesday, October 9, 2019)]
[Rules and Regulations]
[Pages 53995-53997]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-21794]



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 Rules and Regulations
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  Federal Register / Vol. 84 , No. 196 / Wednesday, October 9, 2019 / 
Rules and Regulations  

[[Page 53995]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2019-0488; Special Conditions No. 25-756-SC]


Special Conditions: Voyageur Aerotech Inc., Bombardier DHC-8-100, 
DHC-8-200, DHC-8-300 and DHC-8-400 Series Airplanes; Installed 
Rechargeable Lithium Batteries

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Bombardier Model 
No. DHC-8-100, DHC-8-200, DHC-8-300, and DHC-8-400 series airplanes. 
These airplanes, as modified by Voyageur Aerotech Inc. (Voyageur), will 
have novel or unusual design features when compared to the state of 
technology envisioned in the airworthiness standards for transport 
category airplanes. This design feature is a rechargeable lithium 
battery pack inside the Emergency Backup Power Supply. 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: Effective October 9, 2019.

FOR FURTHER INFORMATION CONTACT: Nazih Khaouly, Airplane and Flight 
Crew Interface Section, AIR-671, Transport Standards Branch, Policy and 
Innovation Division, Aircraft Certification Service, Federal Aviation 
Administration, 2200 South 216th Street, Des Moines, Washington 98198; 
telephone and fax 206-231-3160; email [email protected].

SUPPLEMENTARY INFORMATION:

Background

    On September 10, 2018, Voyageur applied for a supplemental type 
certificate for a rechargeable lithium battery pack inside the 
Emergency Backup Power Supply in the Model DHC-8-100, DHC-8-200, DHC-8-
300, and DHC-8-400 series airplanes. The Bombardier Model DHC-8-100, 
DHC-8-200, DHC-8-300, and DHC-8-400 series airplanes are twin engine 
powered airplanes with standard seating provisions for up to 86 
passengers, depending on model, and a maximum takeoff weight of between 
33,000 lbs. and 65,200 lbs., depending on series model.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101, Voyageur must show that the Model DHC-8-100, DHC-8-200, 
DHC-8-300, and DHC-8-400 series airplanes, as changed, continue to meet 
the applicable provisions of the regulations listed in Type Certificate 
No. A13NM or the applicable regulations in effect on the date of 
application for the change, except for earlier amendments as agreed 
upon by the FAA.
    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 Bombardier Model DHC-8-100, DHC-8-
200, DHC-8-300, and DHC-8-400 series airplanes because of a novel or 
unusual design feature, special conditions are prescribed under the 
provisions of Sec.  21.16.
    Special conditions are initially applicable to the model for which 
they are issued. Should the applicant apply for a supplemental type 
certificate 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.
    In addition to the applicable airworthiness regulations and special 
conditions, the Bombardier Model DHC-8-100, DHC-8-200, DHC-8-300, and 
DHC-8-400 series 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 14 CFR 11.19, in 
accordance with Sec.  11.38, and they become part of the type 
certification basis under Sec.  21.101.

Novel or Unusual Design Features

    The Bombardier Model DHC-8-100, DHC-8-200, DHC-8-300, and DHC-8-400 
series airplanes will incorporate the following novel or unusual design 
feature:
    The installation of a rechargeable lithium battery pack inside the 
Emergency Backup Power Supply. Known uses of rechargeable and non-
rechargeable lithium batteries on airplanes include:
     Flightdeck and avionics systems such as displays, global 
positioning systems, cockpit voice recorders, flight data recorders, 
underwater-locator-beacons, navigation computers, integrated avionics 
computers, satellite network/communication systems, communication 
management units, and remote monitor electronic line replaceable units;
     Cabin safety, entertainment and communications equipment 
including emergency locator transmitters, life rafts, escape slides, 
seat belt air bags, cabin management systems, Ethernet switches, 
routers and media servers, wireless systems, internet/in-flight 
entertainment systems, satellite televisions, remotes and handsets; and
     Systems in cargo areas including door controls, sensors, 
video surveillance equipment and security systems.

Discussion

    Rechargeable lithium batteries are considered to be a novel or 
unusual design feature in transport category airplanes, with respect to 
the requirements in Sec.  25.1353. 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. These batteries introduce higher energy levels into 
airplane systems through new chemical compositions in various battery-
cell sizes and construction. Interconnection of these cells in battery 
packs introduces failure modes that require unique design 
considerations, such as provisions for thermal management.
    These special conditions are substantively similar to special 
conditions the FAA has released in the

[[Page 53996]]

past. The special conditions have been drafted into a plain English 
format, reorganized for clarity, and provide more prescriptive 
instructions than previously released special conditions.
    Special Condition 1 requires that each individual cell within a 
battery be designed to maintain safe temperatures and pressures. 
Special Condition 2 addresses these same issues but for the entire 
battery. Special Condition 2 requires that the battery be designed to 
prevent propagation of a thermal event, such as self-sustained, 
uncontrolled increases in temperature or pressure from one cell to 
adjacent cells.
    Special Conditions 1 and 2 are intended to ensure that the cells 
and battery are designed to eliminate the potential for uncontrollable 
failures. However, a certain number of failures will occur due to 
various factors beyond the control of the designer. Therefore, other 
special conditions are intended to protect the airplane and its 
occupants if failure occurs.
    Special Conditions 3, 7, and 8 are self-explanatory, and the FAA 
does not provide further explanation for them at this time.
    Special Condition 4 clarifies that the flammable-fluid fire-
protection requirements of 14 CFR 25.863 apply to rechargeable lithium 
battery installations. Section 25.863 is applicable to areas of the 
airplane that could be exposed to flammable fluid leakage from airplane 
systems. Rechargeable lithium batteries contain electrolyte that is a 
flammable fluid.
    Special Condition 5 requires each rechargeable lithium battery 
installation to not damage surrounding structure or adjacent systems, 
equipment, or electrical wiring from corrosive fluids or gases that may 
escape in such a way as to cause a major or more severe failure 
condition. Special Condition 6 requires each rechargeable lithium 
battery installation to have provisions to prevent any hazardous effect 
on airplane structure or systems caused by the maximum amount of heat 
it can generate due to any failure of it or its individual cells. The 
means of meeting special conditions 5 and 6 may be the same, but they 
are independent requirements addressing different hazards. Special 
Condition 5 addresses corrosive fluids and gases, whereas special 
condition 6 addresses heat.
    Special Condition 9 requires rechargeable lithium batteries to have 
automatic means, for charge rate and disconnect, due to the fast acting 
nature of lithium battery chemical reactions. Manual intervention would 
not be timely or effective in mitigating the hazards associated with 
these batteries.
    Although these special conditions require specific functionalities 
and capabilities, and address certain critical failure modes of 
rechargeable lithium batteries and their installations, the applicant 
must also meet the requirements of Sec. Sec.  25.1301, 25.1309, and 
25.1709, when applicable, in addition to these special conditions. To 
date, in-service experience has shown that rechargeable lithium battery 
thermal/pressure runaway conditions are not extremely improbable. 
Applicants must assume such failures could occur sometime during the 
life of the battery installation when demonstrating compliance with 
Sec.  25.1309.
    If an applicant proposes to install a rechargeable lithium battery 
in a rotor burst zone, the applicant must assess the rotor burst 
induced damage to the battery to show compliance with Sec.  
25.903(d)(1) in conjunction with showing compliance with the 
rechargeable lithium battery special condition.
    These special conditions apply to all rechargeable lithium battery 
installations in lieu of Sec.  25.1353(b)(1) through (4) at amendment 
25-123 or Sec.  25.1353(c)(1) through (4) at earlier amendments. Those 
regulations remain in effect for other battery installations.
    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.

Discussion of Comments

    The FAA issued Notice of Proposed Special Conditions No. 25-19-09-
SC for the Bombardier Model No. DHC-8-100, DHC-8-200, DHC-8-300, and 
DHC-8-400 series airplanes, which was published in the Federal Register 
on July 22, 2019 (84 FR 35041). No comments were received, and the 
special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Bombardier Model DHC-8-100, DHC-8-200, DHC-8-300, and DHC-8-400 series 
airplanes. Should Voyageur apply at a later date for a supplemental 
type certificate to modify any other model included on Type Certificate 
No. A13NM to incorporate the same novel or unusual design feature, 
these special conditions would apply to that model as well.
    Under standard practice, the effective date of final special 
conditions would be 30 days after the date of publication in the 
Federal Register. However, as the certification date for the Bombardier 
Model DHC-8-100, DHC-8-200, DHC-8-300, and DHC-8-400 series airplanes 
is imminent, the FAA finds that good cause exists to make these special 
conditions effective upon publication.

Conclusion

    This action affects only certain novel or unusual design features 
on Model DHC-8-100, DHC-8-200, DHC-8-300, and DHC-8-400 series 
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.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

Authority Citation

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702, 44704.

The Special Conditions

0
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 Bombardier Model DHC-8-100, DHC-8-200, 
DHC-8-300, and DHC-8-400 series airplanes, as modified by Voyageur 
Aerotech Inc.
    In lieu of title 14, Code of Federal Regulations (14 CFR) 
25.1353(b)(1) through (4) at amendment 25-123 or Sec.  25.1353(c)(1) 
through (4) at earlier amendments, each rechargeable lithium battery 
installation must:
    1. Be designed to maintain safe cell temperatures and pressures 
under all foreseeable operating conditions to prevent fire and 
explosion.
    2. Be designed to prevent the occurrence of self-sustaining, 
uncontrollable increases in temperature or pressure, and automatically 
control the charge rate of each cell to protect against adverse 
operating conditions, such as cell imbalance, back charging, 
overcharging, and overheating.
    3. Not emit explosive or toxic gases, either in normal operation or 
as a result of its failure that may accumulate in hazardous quantities 
within the airplane.
    4. Meet the requirements of Sec.  25.863.
    5. Not damage surrounding structure or adjacent systems, equipment, 
or electrical wiring from corrosive fluids or gases that may escape in 
such a way as to cause a major or more-severe failure condition.
    6. Have provisions to prevent any hazardous effect on airplane 
structure or

[[Page 53997]]

systems caused by the maximum amount of heat it can generate due to any 
failure of it or its individual cells.
    7. Have a failure sensing and warning system to alert the 
flightcrew if its failure affects safe operation of the airplane.
    8. Have a monitoring and warning feature that alerts the flightcrew 
when its charge state falls below acceptable levels if its function is 
required for safe operation of the airplane.
    9. Have a means to automatically disconnect from its charging 
source in the event of an over-temperature condition, cell failure or 
battery failure.

    Note: A battery system consists of the battery, battery charger 
and any protective, monitoring and alerting circuitry or hardware 
inside or outside of the battery. It also includes vents (where 
necessary) and packaging. For the purpose of this special condition, 
a battery and the battery system is referred to as a battery.


    Issued in Des Moines, Washington, on September 27, 2019.
James Wilborn,
Acting Manager, Transport Standards Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2019-21794 Filed 10-8-19; 8:45 am]
 BILLING CODE 4910-13-P