Astro SB007 – SL8 Battery Incident

Date Released: Feb 15th, 2024

Subject: SL8 Battery Incident

Effectivity: Immediate

Required Action:  None at this time – Alert

INTRODUCTION

On November 9th, 2023, a customer had an SL8 Battery malfunction and catch fire prior to a flight. The pilot noted that they plugged the SL8 into the Astro, the SL8 screen was non-functional, and tried to turn the battery on without success. The pilot then removed the battery from the aircraft and reconnected it to the aircraft. At this time he reported hearing sparking / arcing.  He disconnected the battery and placed it safely away from the aircraft and the launch site where shortly after the battery had 1 or 2 cells vent and catch on fire.

As of now, there are no required actions and customers are advised to continue normal SL4 / SL8 / Astro operations with extra attention paid to any battery faults or nonfunctional OLED screens.

BACKGROUND

This is the context for the incident:

• Batteries were charged the night before in a hotel room
• They were charged to 100%
• First flight of the morning was the incident flight
• Freefly has investigated our internal tracking for this pack serial number and completed an in depth review to determine the probable root cause of the issue. At this time we have not identified the most likely specific root cause.
• There have been 2 SL8 Battery issues recorded since Astro launch. Freefly has released Service Bulletins for each and will continue to update you if we gain additional information.

DISCUSSION

There are a few potential root causes we are investigating:

• Over-voltage incident causing a component to fail and short the pack causing BMS to catch on fire
  • From Astro or accessories
  • From manufacturing
  • From charging
• Cell balance circuit failure or balance wire short circuit
• Manufacturing error or defect in a PCBA
• Random and catastrophic failure of key component (TVS Diode, Regulator, etc)

RECOMMENDATION

At this time, there is no immediate action required from our customers. Continue to use best Lithium-Ion battery charging and storage safety practices.  

If you have any abnormal battery behavior during use, charging, or storage, please contact Freefly Support to provide information on the issue. As always, use best practices when charging and handling batteries.  And store them in a safe place, away from living spaces and flammable materials.