Electric plane prototype caught fire

[gearlever]

Eviation Alice prototype damaged by electric fire (https://www.flightglobal.com/air-transport/eviation-alice-prototype-damaged-by-electric-fire-in-arizona/136327.article)

Looks like fire started from an external battery unit.
So no worries....

[OldnGrounded]

Yup. As long as the batteries are kept on the ground, everything will be OK.

[ATC Watcher]

Bad times for electric propulsion , a large drone overflying a large crowd in a festival fell in the public in south of France , injuring 2 due to a battery failure,the medium size UK police surveillance drones falling down due to rain in electrical systems and now this ... Lots of work to be done before it is will carry paying pax I would say .

[capngrog]

“Eviation Aircraft experienced a fire incident during system testing of one of its aircraft at the Prescott Regional airport,” the company says in a statement. The incident “is believed to have been caused by a ground-based battery system which was being utilised during rigorous testing of its all-electric airplane”.

" ... ground-based battery system ..." A charging system perhaps? As far as my limited knowledge of the technology goes, most fires involving high energy density batteries, such as Lithium-ion, result from too rapid charging or discharging and result in fires involving the batteries themselves and not the charging systems or discharging loads. Since this incident involves a very promising yet evolving technology, I would think that the NTSB would be interested. The investigation and report should be very interesting.

At least nobody was injured.

[tucumseh]

MoD Lithium-Ion battery trials, 1991

https://i214.photobucket.com/albums/cc291/exploringtheblue/li-ion%208%20mins%20edit_zpsjs5hkjpr.jpg (https://s214.photobucket.com/user/exploringtheblue/media/li-ion%208%20mins%20edit_zpsjs5hkjpr.jpg.html)

[MorayC]

I wonder if they've been testing some kind of battery to battery charging to minimise charging times, and not be restricted by how much mains power is available?

[ThreeThreeMike]

They were using an external battery for testing because the onboard battery had insufficient capacity for the test being performed. The fire started for the reason many electrical fires start, inadequate conductor sizing for the circuit current, and lack of an overcurrent protective device, AKA a circuit breaker.

[Andrewgr2]

That’s shocking if true. And incompetent in the extreme.

[turbidus]

Wow, I fly Cape Air quite often.

[andrasz]

Am I the only one wondering about the wisdom of merrily dousing an electric fire with water and foam ... ?
(video in OP)

[Twitter]

Depends what you are trying to save - on the ground.

On the other hand don’t spill your coffee on the pedestal - in flight.

[capngrog]

You have touched on what will be a BIG problem for aircraft accident Emergency Responders. Electric automobiles are already a BIG problem for Emergency Responders, with the Tesla system using around 375 volts and the Porsche Taycan about 800 volts. Dousing a flaming wreck with water and foam is usually the only option for most Fire Fighting organizations and is usually effective on hydrocarbon fuel fires; however, the materials used in the current crop of high energy density (HED) batteries (such as Lithium) are pyrophoric and ignite when exposed to air. Lithium will also react with water, but at a much slower rate than, for example, Sodium metal. The technology of HED batteries is rapidly evolving, and my limited understanding of their chemistry may be outdated, but the electrical hazard is pretty much a given. Isolation switches for an HED battery will confine electrical hazards to the battery pack itself if electrical circuits are undamaged; however, it can be expected that most systems will be damaged or otherwise compromised in an aircraft accident. Physical damage to the batteries themselves can also cause fire. I'm not sure that the hazards associated with electric-powered flight are fully understood at this point in time. I can say for certain, however, that those hazards are not fully understood by me.

Hopefully, there will be other posters on this thread who have a more complete understanding of the hazards associated with electric-powered flight.

[Ex Cargo Clown]

Pretty sure they use a lithium polymer which isn't pyrophoric and not elemental lithium. If you go down the group 1 metals, Li is the least reactive and doesn't really burn in water either. It needs a lot of energy to combust, hence water being a good way of putting it out as it's self-fueling otherwise.

(This post is brought to you by an ex-chemistry student who managed to blow a phone battery up in a pumpkin and completely destroy it. I wouldn't fly in a Li-ion aircraft).

[MCR01]

Well it's evolving technology so problems will continue to appear.
I do fly a Li-Ion powered self launch glider; I used to fly a gasoline powered self launch. Having 22 litres of petrol inches from your right shoulder in a millimetre thin GRP tank does not feel comfortable either!
It's a choice....

[unmanned_droid]

The Rimac that Richard Hammond crashed was catching fire due to battery cell shorts for 5 days after the crash.

I read a post from a fireman that said Tesla had held a training event to show the guys how to isolate and disconnect the batteries in a crash scenario, however this doesn't help with damaged cells. He confirmed the requirement to attend the crash for a long period of time to make sure any other shorts don't cause other fires.

He then went on to say that if you wanna talk about scary, consider hydrogen powered vehicles.

[Atlas Shrugged]

Hopefully, there will be other posters on this thread who have a more complete understanding of the hazards associated with electric-powered flight.

I think we are a very, very, very long way from being anywhere near that position!

[Winemaker]

MCR01

I'm curious. 22 liters of petrol is about 16.5 kg providing about 45 MJ/kg, so about 740 MJ total energy. Assuming 25% efficiency of a piston engine, that's about 185 MJ of available energy. Lithium batteries (middle range) energy density is 0.6 MJ/kg. So, assuming 100% efficiency of the electric side, that means that to equal the energy of the petrol, one would need a battery pack weighting 185 kg. How could this possibly work? Have I made a maths error?

[capngrog]

The first aircraft crash I responded to was a Lockheed Jetstar that aborted its takeoff from 09L at MIA. The first officer was able to exit the cockpit window, but the captain perished in the post crash fire. The initial fire was extinguished, but fire continued to erupt for several hours after the crash until the battery was finally disconnected. Depending on the aircraft, the battery voltage is somewhere around 28 V DC, so I can imagine the problems that may be associated with the crash of an electrically-powered aircraft featuring voltages of around 400-800 V DC (or more).

[unmanned_droid]

Nope, not really. That's the entire electric propulsion problem in a nutshell.

[Mr Optimistic]

How do you protect the main drive from an overcurrent fault if you can't isolate the supply without loss of lift?

[Genghis the Engineer]

I suspect that anybody who genuinely knows detail about the cause of the accident isn't putting that knowledge in the public domain this quickly.

But, generically the major issue with Lithium battery fire risk is thermal runaway, cause by some problem of battery thermal management. That can be poor storage, physical damage, incorrect charging cycles - there are plenty of opportunities. The phone industry are reasonably mature in their understanding of that, but with the best will in the world, you can't instantly map knowledge applicable to a $10 phone battery to a $200k aeroplane battery array. There will be more accidents like this, hopefully with similar limitations to only property damage and not loss of life, as our communities develop this knowledge.

Onboard lithium fires in carry on devices, incidentally, are recommended (on the back of quite a lot of research by FAA in particular) to be handled with lots of water - so the use of large quantities of water and foam in this case, would seem entirely consistent. Other firefighting compounds are less likely to cool effectively, and the combustion process does not require external oxygen, so simply excluding air doesn't get you very far.

Most expert commentators have considered the various media releases by Eviation about progress on the Alice to be basically exaggeration and hyperbole. It will be interesting to see how those modify in the light of this.

[DaveReidUK]

Was the fire in a hangar?

[Andrewgr2]

I reckon the 16l of petrol carried in my self sustaining (turbo) glider would give me a total of about 20,000 feet of climb. From what I hear, electric self launchers would do about 4000’ at best. In practice they usually use another form of launching to preserve their battery for getting home when the lift runs out. At low power they will fly a fair distance - certainly enough to get to a landable field, and usually enough to get home. Electric passenger transport is a very different matter!

[Genghis the Engineer]

There are photographs and video online which appear to show the fire to be consuming the aeroplane, which is in the middle of an open hard area.

[Deltasierra010]

The 25% efficiency of a 2 stroke self launcher or sustainer is very optimistic, the current crop of jet sustainers are outrageously thirsty.
Agree about electric aviation in general, maybe small recreational or training types, not passenger carrying.

[Petit-Lion]

Nope, not really. That's the entire electric propulsion problem in a nutshell.
Battery vs petrol tank is at 1 to 10 disavantadge, but given that the electric motor is so much lighter than the gas engine, this brings the disavantadge of the current electric propulsion down to around 1 to 5. That's why an electrified aircraft has usually 1/5 the range (or climbing potential) of the petrol-powered version. Still useful in some applications like training or very short-haul transportation.
OTOH, the King-Air-like Eviation specs sound very optimistic at best. These 260 Wh/kg batteries still are in the "experimental" class of performance, and they need to stuff them in a 1600 kg airframe, motors and 11 seats included.

[Winemaker]

And there's not just that to consider; the plane weights the same coming down as it did going up......

[jeepjeep]

Maybe Tesla has some ideas for resolving this problem. Oh, never mind...

https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/992x558/teslafire_5a5b455caaa61317b214369ac67a0c2dcbfcd004.jpg
Batteries running a little warm today

:)

[horizon flyer]

MCR01

I'm curious. 22 liters of petrol is about 16.5 kg providing about 45 MJ/kg, so about 740 MJ total energy. Assuming 25% efficiency of a piston engine, that's about 185 MJ of available energy. Lithium batteries (middle range) energy density is 0.6 MJ/kg. So, assuming 100% efficiency of the electric side, that means that to equal the energy of the petrol, one would need a battery pack weighting 185 kg. How could this possibly work? Have I made a maths error?

Very true but you have to consider the complete package of IC engine and fuel source so even if the battery is heavy the motor is lighter, example 300hp motor 15kg but it does rotate at 20,000 rpm so needs a gear box. But you are correct at the moment batteries are to low in power density, the break point seems to be 500W/h/Kg still heavy but feasible, once they hit 2.5Kwh/Kg then IC engines are totally finished this will happen.