In-flight Lithium-Ion Battery Fires: Are you Prepared?

Have a guess within a few seconds: How many lithium-ion batteries do you think are on board during your typical flight? 🔋

We asked ourselves the exact same question in our HEMS equipped AW169.

The answer?

More than 30…

On a typical airline flight it’ll be hundreds, if not thousands.

Every lithium-ion battery is an opportunity for an onboard fire 🔥

The problem is that this type of fire is almost impossible to extinguish, you could shoot it into outer space and it will still burn.

We are still years away from being able to deal with lithium-ion battery fires / thermal runaway.

Many airlines like Emirates have already banned using a powerbank in flight for passengers.

In 2024 (in the USA), the average amount of in-flight lithium-ion battery fires was 2 per week!

We take a look at what we could actually do about this in the aviation industry ⤵️

We don’t publish all our Notes from the Cockpit (like this one) publicly, some are shared only by email. Get the next one sent straight to your inbox ⤵️

🔥 What is a Lithium-Ion Fire or Thermal Runaway?

Lithium-ion batteries are everywhere in modern cockpits. You can have:

🔸 iPads / EFB’s (electronic flight bags)

🔸 Torches / flashlights

🔸 Galley equipment

🔸 Night vision goggle battery packs

🔸 Portable radios

🔸 Countless phones / laptops / headsets

🔸 Medical monitors (in HEMS/air ambulance)

The problem is that lithium-ion batteries don’t just “catch fire” like paper or wood.

They go into what’s called thermal runaway.

Here’s what that means:

1️⃣ Overheating starts: from physical damage, overcharging, manufacturing defects, or even just age.

2️⃣ The electrolyte inside the battery begins to break down, releasing flammable gases. The reaction generates its own oxygen, which means it becomes self-sustaining.

3️⃣ Temperatures spike, we’re talking over 1,000°C!

4️⃣ Neighbouring battery cells heat up too, causing a chain reaction.

Once it kicks off, a lithium-ion battery can effectively fuel itself.

A lithium-ion battery fire often burns until the chemical fuel is completely exhausted.

🔸 The electrolyte (a flammable organic solvent) is the main fuel.

🔸 Oxygen is released from the cathode material as it breaks down at high temperature.

🔸 Because the fuel and oxidiser are both inside the cell, traditional extinguishers can’t really “starve” the fire.

What about the threats? The danger isn’t just the fire. There are a few other things that are difficult to manage or contain:

🔸 Toxic fumes (hydrogen fluoride, carbon monoxide, and more)

🔸 Explosion risk from pressure build-up

🔸 Re-ignition hours later if the battery’s still hot inside

All threats that are hard to manage, especially in flight!

For more detail on Threat and Error Management, have a read of our TEM article:

Keeping it Simple: Threat and Error Management as a Pilot

💧 How to Deal With a Lithium Ion Battery Fire?

As we’ve already mentioned, you can’t “extinguish” a lithium-ion fire in the same way you’d put out a “normal” galley fire or an engine fire.

What you can do is slow it down, cool it, and contain it until you land.

Even Halon doesn’t cut it!

Halon is brilliant for smothering flames in conventional fires because it removes the oxygen from the reaction.

But remember: lithium-ion cells produce their own oxygen during thermal runaway. It’s like trying to put out a match that’s also a tiny oxygen tank.

So what CAN we do?

🔸 Identify the fire: Smell: a sweet, metallic, solvent-like odour. Sound: popping, hissing, or crackling. Visual: smoke or swelling device casing

🔸 Communicate: Alert the rest of the crew. If passengers are on board, brief them on your intentions

🔸 Isolate the power: If it’s a plugged-in device, unplug it immediately. Remove any connected batteries if possible

🔸 Cool it down: Many regulators now recommend use of water or non-flammable liquids (soft drinks, juice, coffee, etc.) if a battery goes into thermal runaway.

🔸 Contain: Use a lithium-ion containment bag, or wrap in a fire blanket and place in a secure metal container (some operators use galley ovens for this in fixed-wing)

🔸 Ventilate: Open vents or use environmental controls to clear toxic fumes from the cockpit/cabin

🔸 If you can’t contain the fire – Land: “As soon as practical” may still mean a controlled diversion, you don’t want to rush a hazardous landing in an unsuitable location, it depends on the circumstances.

Notice what’s missing? “Extinguish”.

Because that’s not usually possible until the battery has completely burnt itself out!

💡 What can the Aviation Industry do to Manage Lithium Ion Fires?

This is where it gets interesting. As pilots and operators, we’re basically stuck with whatever fire suppression the aircraft came with, plus any portable gear we bring.

But there’s a lot the industry could (and should) do better.

1) Standardise Crew Procedures

Formalised training on the steps to take would go a long way. To summarise:

🔸 Reduce visible flames

🔸 Immediately cool the device thoroughly

🔸 Isolate, monitor, and be ready for re-ignition

Operators can help by adding a one-page QRH card in every cockpit / galley.

2) Equip cabins for isolating or cooling, not just extinguishing

🔸 Ensure abundant water availability and PPE (gloves/masks).

🔸 Containment bags/boxes

🔸 Timing is everything, make equipment easy to reach and use

3) Tighten regulation on using powerbanks in flight

🔸 Regulators could consider in-flight charging restrictions for power banks/loose spares (several airlines have moved this way in 2025).

🔸 If seat-USB is available, encourage using the aircraft’s power, and discourage use of powerbanks in flight.

4) Use scenario based training & measure outcomes

🔸 Run short, realistic drills: Device overheating on a passenger, or in galley bin, in the overhead storage, or in the cockpit.

🔸 Time the crew from detection ➡️ Halon ➡️ sustained water cooling ➡️ containment ➡️ comms.

🔸 Share identified events internally and with the aviation community, so everyone can learn from different situations

Conclusion

Next time you walk into the cockpit for a flight, ask yourself:

How many lithium-ion batteries are on board today?

And

If one went into thermal runaway right now, what’s our plan?

The answers might surprise you, it definitely surprised us!