What happened
During the descent into Hobart, a lithium-on power bank stored in an overhead locker experienced a failure in one of its cells. The device, which was stored with an uncovered port and a cable attached, underwent thermal runaway, leading to the emission of smoke and subsequent flames.
As the aircraft was already descending, the cabin crew had a very narrow window of time to respond. Within approximately eight minutes, the crew identified the fire, retrieved necessary firefighting equipment, and worked to suppress the flames. During the incident, the crew also notified the flight crew and relocated passengers to different seats. Due to the time pressure of preparing the cabin for landing, the crew was unable to remove the damaged power bank from its backpack or place it in a fire containment bag. Instead, the device remained in the overhead locker, partially submerged in water used to extinguish the fire.
The investigation
The investigation focused on the cause of the battery failure and the effectiveness of the emergency response. While no pre-existing damage to the power bank was identified, investigators noted that the presence of a cable and exposed ports could have contributed to the fault.
Regarding the crew's response, the investigation found that the timing of the event—occurring during the descent phase—severely limited the ability of the crew to execute all trained procedures. Furthermore, while protective breathing equipment (PBE) was available, two crew members found the equipment ineffective due to issues with fitment, visibility, and communication. This lack of effective protection placed the crew at an increased risk of smoke inhalation.
Findings
- The primary cause of the fire was the thermal runaway of a lithium-ion power bank cell.
- The storage of the power bank with an attached cable and exposed ports may have increased the risk of a malfunction.
- The timing of the fire during the descent phase restricted the crew's ability to complete all standard lithium battery fire management procedures.
- The protective breathing equipment provided was not sufficiently effective for the crew to use during the emergency due to fitment and visibility issues.