FAA’s path on Lithium Ion Battery Approval Standards

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Lithium Battery receives FAA approval

FAA”s standards evolve from 2013

Critical for future evolution of aviation- eVTOL and electric airplanes

The future of UAS aircraft (especially the eVTOL vehicles) and green, electric aircraft depends on innovation in battery technology. True Blue Power expresses its appreciation for the FAA’s constantly exacting standards applied to their products.

Below are the significant milestone along that regulatory path.

True Blue Power Awarded FAA’s Highest Level Of Lithium Battery Approval

Receives Sweeping Certification For Three Main Ship Batteries

True Blue Power, a manufacturer of lithium-ion aircraft batteries, has announced the TSO certification of the company’s entire Gen5 main ship battery family. The TB20 (20 amp-hour), TB30 (30 amp-hour) and TB40 (40 amp-hour) received an impressive C179b CLASS A-4B rating, meeting the Federal Aviation Administration’s (FAA) latest and highest level of lithium battery requirements.

We commend the FAA on continuously evaluating and improving the standards by which lithium products are determined safe,” said Brett Williams, True Blue Power Director of Engineering. “The latest certification requirements were significant and challenging, but equally important,” Williams continued. “The certification of all three Gen5 batteries at the same time, to such rigorous requirements, is uncommon and a great accomplishment.”

FAA’s path on Lithium Ion Battery Approval Standards


      • Battery Thermal Runaway Containment: Level A (Highest)
      • Maximum Energy Category: Level 4 (Highest)
      • Emissions Control: Level B (Completely contained within vent design)

True Blue Power Gen5 Battery DO-311A and DO-160 Testing Included (but was not limited to):

      • Battery Thermal Runaway Containment
      • Constant Voltage Discharge
      • Drop Impact Resistance
      • Explosion Containment
      • Over Discharge With/Without Protection
      • Overcharge Protection
      • Rated Capacity at Low/High Temperature
      • Rapid Discharge at High Temperature
      • Short Circuit With/Without Protection
      • Single Cell Thermal Runaway Containment

Battery configurations programmed for each specific aircraft
Charge current limit, end-of-life capacity, minimum dispatch capacity and engine-start readiness


That’s high praise on a complex and critical safety technology. Here is a little of how the FAA and industry have arrived at this pinnacle (?):

FAA Takes Action On The Airworthiness Of B-787 Batteries In Face Of NTSB “Investigative Hearing”

Aviation Subcommittee Hearing On Lithium-Ion Battery Incident Is Constructive And Not Sensational

NTSB Issues Recommendations About Lithium-Ion Batteries; What Will FAA Do In Response?

NTSB Issues Its 2nd Report On The Lithium-Ion Battery. What Is The Impact On The Safety Process For That Precedent?

NTSB Recommendation A-104 drove industry, RTCA and the FAA to enhance the standards for Lithium Ion batteries—

RTCA DO-347-Certification Test Guidance for Small and Medium Sized Rechargeable Lithium Batteries and Battery Systems

This document provides test guidance and installation considerations for Small and Medium Sized Rechargeable Lithium Batteries and Battery systems that are permanently installed on aircraft. The tests defined in this document also provide a standardized method for characterization of performance of batteries and battery systems. Compliance with these standards is recommended as a means of assuring that the batteries and battery systems will perform their intended function(s) safely under conditions encountered in aeronautical operations.

AC 20-184 – Guidance on Testing and Installation of Rechargeable Lithium Battery and Battery Systems on Aircraft


The guidance in this AC is intended for manufacturers, installers, maintenance personnel, and users of installed rechargeable lithium batteries and battery systems on aircraft. As with all advisory material, this AC is not mandatory and does not constitute a regulation. It is issued for guidance purposes and to outline a means of compliance with applicable airworthiness requirements.

This advisory circular (AC) provides manufacturers and installers with an acceptable means of compliance to meet the installation, operation, maintenance and airworthiness requirements for installation of lithium batteries on aircraft (14 CFR part 21, 23, 25, 27 and 29).

AC 20-184 A – Guidance on Testing and Installation of Rechargeable Lithium Battery on Aircraft


Gives an acceptable means to show compliance to the airworthiness requirements for installed rechargeable lithium battery and battery systems on aircraft using standards provided in RTCA, Inc., documents RTCA DO-347 and RTCA DO-311ND





NTSB A-104 was marked as “Open Acceptable Response-FAA” on 9/20/2018 based on this response from FAA Acting Administrator


“From Daniel K. Elwell, Acting Administrator:

The Federal Aviation Administration (FAA) agrees that consistent and standardized test methods are necessary to facilitate certification of new aircraft designs that incorporate a permanently installed rechargeable lithium- ion battery. For new transport airplane certification projects, the FAA issues special conditions for applicants whose designs include rechargeable lithium-ion or other lithium based batteries. These special conditions provide adequate certification standards.

The FAA worked with RTCA to approve a revision to RTCA 00-3 11, Minimum Operational Performance Standards for Rechargeable Lithium Battery Systems, for large battery systems. On December 19. 2017, the RTCA released RTCA 00-3 11 A, which contains abuse tests that subject a single cell within a permanently installed, rechargeable lithium-ion battery to thermal runaway and demonstrate that the battery installation mitigates all hazardous effects of propagation to other cells and release of electrolytes, fire. or explosive debris outside the battery case. The tests will replicate the battery installation on the aircraft and be conducted under conditions that are considered to produce the most severe outcome.

The FAA incorporated RTCA 00-311 A into the revision of Technical Standard Order (TSO)-C 179a. Permanently Installed Rechargeable Lithium Cells, Batteries and Battery Systems. TSO-C l79b was released on March 23. 2018 and is available at the following website: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgTSO.nsf/0/67 FF4FD73B2DEF078625825F00716B87?0pen0ocument.

On October 15, 2015, the FAA issued Advisory Circular (AC) 20-184, Guidance on Testing and Installation of Rechargeable Lithium Battery and Battery Systems on Aircraft. to provide guidance for complying with the special conditions to meet the installation, operation, maintenance, and airworthiness requirement s for installation of lithium batteries on aircraft. AC 20- 184 invokes RTCA 00-31 1 and RTCA 00-347. Certification Test Guidance for Small and Medium Sized Rechargeable Lithium Batteries and Battery Systems, and also provides guidance on how to obtain installation approval for permanently installed rechargeable lithium-ion batteries and battery systems on aircraft.

The FAA is revising AC 20-184 to invoke RTCA D0-31lA as one means of compliance to the special conditions regarding rechargeable lithium-ion battery systems. Until the AC 20-184A revision is released, the FAA will utilize issue papers to inform applicants of the effects of battery cells going into thermal runaway. In the meantime, all current projects will utilize RTCA D0-31 l A and RTCA 00-347 as a means of compliance.

The 17AA expects the revised AC 20-184A to be released in December 2018. [final] The FAA is reviewing the in-service performance and methods of compliance used to certify permanently installed rechargeable lithium-ion batteries on in-service aircraft to determine design/installation and certification details. This review, supplemented by a review of service difficulties, has not yet identified a need for corrective airworthiness action. We will continue to monitor permanently installed rechargeable lithium-ion battery system performance as part of our normal continued operational safety processes.

A record of refining the certification for Lithium Ion batteries sets a matrix for adjusting to new technology. Hopefully the next disruptive introduction of innovation will start with initial reference to ASTM and RTCA. AS recently learned industry has greater insights into these developments, but the intensity of the adoption of advances requires that a third party with a high level of technical capabilities assists the FAA in the safety oversight function as a prerequisite to certification.



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