A Smoking Power Bank Put Southwest’s Brand-New Safety Rule to the Test Just One Day After it Was Introduced

The strict new rules that Southwest Airlines introduced last week to guard against safety concerns from overheating portable power banks was put to the ultimate test just one day into the regulations taking effect.

As Southwest Flight WN-1844 was flying at 40,000 feet off the coast of South Carolina on Thursday, the pilots of the Boeing 737 were forced to make an emergency diversion when a power bank overheated and started to spew smoke into the cabin.

The incident occurred as the plane was making a regularly scheduled flight from Baltimore to Tampa, and although an emergency was declared, the flight attendants were able to quickly contain the power bank and stop the dangerous situation from getting any worse.

A day earlier, Southwest Airlines became the first carrier in the United States to introduce new rules surrounding the use of portable power banks on its flights.

Since May 28, passengers must keep their power banks within easy reach and must not charge devices when the power bank is locked out of sight in a bag in the overhead locker.

The safety rules stem from a serious aviation accident in January when a portable power bank overheated and set on fire while in the overhead locker of an Air Busan aircraft in South Korea as it was preparing for departure.

The fire quickly spread, and the plane was engulfed in flames. Thankfully, everyone onboard the aircraft was able to evacuate via the emergency slide,s with only minor injuries reported.

In light of that incident, several major international carriers, including the likes of Singapore Airlines, have banned passengers from charging their devices with portable power banks while they are hidden away in hand luggage in the overhead bins.

The idea is that passengers and crew can quickly spot when a portable power bank has dangerously malfunctioned and contain the device before a fire takes hold.

While a growing number of airlines around the world are taking action to prevent a repeat of Air Busan flight BX391 in January, Southwest Airlines remains the only US carrier to have placed restrictions on the use of portable power banks.

“Last week, Southwest introduced a first-in-industry Safety policy requiring Customers to keep portable charging devices visible while in use during flight,” the airline told us in a statement.

“Using portable charging devices while stored in a bag or overhead bin will no longer be permitted. Nothing is more important to Southwest than the Safety of its Customers and Employees,” the statement continued.

The spokesperson noted that the flight attendants onboard Flight 1844 were able to quickly isolate the smoking power bank and put it in a special fire containment bag, which is designed to suffocate any fire of oxygen.

The airline is investigating the incident, and that will no doubt include looking into whether the new power bank rules helped or whether even more action is required.

Any device powered by a lithium battery–be it a cellphone, laptop, e-cigarette, or power bank has the potential to overheat and catch fire. This process is called ‘thermal runaway.’

The term ‘thermal runaway’ comes from the fact that Lithium-ion batteries are made of lots of fuel cells. When one cell overheats, this can quickly spread to the next cell and so on until the power bank explodes into flames.

A thermal runaway can cause lots of heat, sparks, fire, and smoke and can be very difficult to extinguish.