Multirotor crash results in brush fire at Baylands Park in Sunnyvale Ca.

[JohnC]

I pulled into the parking lot at Baylands park for my first flying experience there this morning.

As I walked up to some RC enthusiasts at the park I noticed smoke coming from the 'wetlands' area to the east of the grassy area. Two individuals were over there and it looked like they were tending to whatever was causing the column of smoke.

The wetlands area is NOT wet. whether a result of the drought in California, or for some other reason, this area is dry as tinder.



I walked over to the Southwest corner of the grassy area to see the two individuals start to walk towards the fence, then head away from the grassy area one of them carrying a large multi-rotor, possibly a large hex-copter. The other carrying what looked like a rectangular frame. A fellow ahead of me that went down to investigate had a cell phone out and was calling the fire department as the smoke transitioned into a wall of flames.

Someone flying a quad copter piloted the craft over the ignition point.

By the time the fire department responded with a pair of fire engines, (which was AFTER the individuals put their gear in their vehicle and left the scene) the flames were spreading in all directions. The fireman had to lay hoses, get the hoses hooked up and drag them through a gate and across the field. By the time they started to apply water to the flames, the area burning was about 3 acres, and the flames were heading towards a wooden soundwall next to the freeway (highway 237).

By the time the fire was contained, perhaps 15 acres had burned. Other fire engines were deployed on the edge of the freeway and they had attacked the flames from the east.

Witnesses reported that the fire had started as the result of a multirotor crash. That the two individuals had been flying a pair of large hex copters.

This event raises a large number of questions.

I'm going to subscribe to this thread and see if the other members of the thread raise the many questions that are already in my mind.

 

[RAM]

This was always going to happen. Could be a ban on LIPO's now in favor of LIFE's

The sad thing is they probably could have contained it quick if they had sand, or even a shovel to throw dirt on the battery.

 

[JohnC]

So here is my first question:

A witness thought that a LiPo or ESC could overheat and catch fire if the rotation of the motor was prevented while the throttle was on, or if the aircraft was damaged in a crash such that the ESC was locked in an 'open throttle' condition.

Is this true?

Does that make any landing/crash of an electric motor based aircraft dangerous (if the propeller is physically prevented from turning while the throttle is still on)?

If an ESC can overheat in this way, it wouldn't matter what sort of battery was used.

 

[JohnC]

This was always going to happen. Could be a ban on LIPO's now in favor of LIFE's

The sad thing is they probably could have contained it quick if they had sand, or even a shovel to throw dirt on the battery.

See my first question, above.

As to containment. The crash was in tall, dry grass, about 100 yards from where the pilots were described as standing - on the other side of a fence. Tomorrow I'm going to return to the park and figure out if the gate is locked. The firefighters carried these rake/hoe devices and went through a gate in the fence.

That is the only sort of device I could see an individual being able to take to the crash site quick enough to put out the fire.

 

[RAM]

So here is my first question:

A witness thought that a LiPo or ESC could overheat and catch fire if the rotation of the motor was prevented while the throttle was on, or if the aircraft was damaged in a crash such that the ESC was locked in an 'open throttle' condition.

Is this true?

Does that make any landing/crash of an electric motor based aircraft dangerous (if the propeller is physically prevented from turning while the throttle is still on)?

If an ESC can overheat in this way, it wouldn't matter what sort of battery was used.

I still think there was enough time for them to put the fire out if they were prepared. They did after all recover the copter.

The motor and ESC are always attached to the craft. The battery is always removable. Seems more likely they tossed the battery.

Could you heat up a motor and smoke the varnish on the wires with too much current through one winding, yes.
Can components on the ESC board fail and smoke, yes.
The battery being damaged is still the most likely culprit here. It provides all the energy.

I hope they had the sense to call the fire department.

 

[Multirotorflyer]

I am close to the pilots in question in this thread and have heard the report first-hand.

They were flying from the grassy area but their craft was over the 'wetlands'.

An ESC shorted/failed mid-air and the hex tumbled. They jumped over the fence to retrieve the hex and as they got close, they saw smoke. There were two points of ignition - the battery (shorted as a result of the failed ESC) and the ESC itself. The battery (separated and a few feet from the hex) was picked up and did not catch the dry grass on fire - the ESC did.

Although the fire was only about a foot in diameter upon their arrival, it was clear that after maybe 10-15 seconds they could not put out of the fire and they could see that people were already calling 911. They packed up their car and after seeing the fire trucks arrived and for better or worse, they left. An unfortunate incident all around.

 

[RAM]

I am close to the pilots in question in this thread and have heard the report first-hand.

They were flying from the grassy area but their craft was over the 'wetlands'.

An ESC shorted/failed mid-air and the hex tumbled. They jumped over the fence to retrieve the hex and as they got close, they saw smoke. There were two points of ignition - the battery (shorted as a result of the failed ESC) and the ESC itself. The battery (separated and a few feet from the hex) was picked up and did not catch the dry grass on fire - the ESC did.

Although the fire was only about a foot in diameter upon their arrival, it was clear that after maybe 10-15 seconds they could not put out of the fire and they could see that people were already calling 911. They packed up their car and after seeing the fire trucks arrived and for better or worse, they left. An unfortunate incident all around.

Not sure what the laws are there but they might get fined even though it was an accident. Just very bad luck that the esc got near some tinder. In hindsight we can say it was risky to fly over dry grass but the odds of all that coming together at the same time are pretty low. They might want to check the motor just in case it seized and was the cause of the esc burn out.

 

[nerdnic]

Crazy to see this happen at my home field!

 

[JohnC]

I am close to the pilots in question in this thread and have heard the report first-hand.

They were flying from the grassy area but their craft was over the 'wetlands'.

An ESC shorted/failed mid-air and the hex tumbled. They jumped over the fence to retrieve the hex and as they got close, they saw smoke. There were two points of ignition - the battery (shorted as a result of the failed ESC) and the ESC itself. The battery (separated and a few feet from the hex) was picked up and did not catch the dry grass on fire - the ESC did.

Although the fire was only about a foot in diameter upon their arrival, it was clear that after maybe 10-15 seconds they could not put out of the fire and they could see that people were already calling 911. They packed up their car and after seeing the fire trucks arrived and for better or worse, they left. An unfortunate incident all around.

Thank you very much for the information as to the cause and what happened when they got to the crash site.

When I got out of my car in the parking lot, the smoke was from an area maybe 15 ft in diameter. When I started walking towards that end of the park, I could see flames, and the two had just gotten past the fence.

For better or worse, they left.

I can sympathize, when I saw them leave, I had very mixed emotions. At that point, my thoughts were:

"what would I do?" Would I leave, or would I stay.

I have this attitude that accidents happen and police and fire departments 'protect and serve'. This was an accident. No one got hurt, some dry grass got burned. No big deal (in this case). A total of 4 fire engines (two in the park and two on the highway) fought the fire. Another 4 (or more) fire engines arrived and stood by. A half dozen police units showed up (and did nothing but stand around). One crime scene investigator interviewed everyone who saw the beginning of the event. Names were taken. No one knew who the individuals were.

I've heard stories of municipalities fining those responsible for the 'cost' of the effort to put out the fire.

Had the fire department deployed a drone as soon as the call came in and accessed what was happening, the response would have been much more efficient. If a Cal Fire Unit had been called in, they could have driven onto the 'wetland' and put the fire out in minutes, instead of the hour or so it took. The Sunnyvale fire units had to drag hoses through a fence and around 15 acres of brush. hmmm.

So, to my way of thinking, there is no 'cost', this is what the fire department is for, and their response was professional and measured, but it could have been so much more efficient.

 

[JohnC]

Crazy to see this happen at my home field!

Were you there today?

I'll be there tomorrow, Sunday morning.

 

[ZoomNBoom]

If an ESC can overheat in this way, it wouldn't matter what sort of battery was used.

It sure does. Lipo batteries are well known to be fire and even explosion hazards when shorted, overloaded, overheated overcharged or physically damaged. Life(Po4) batteries are far more stable and will pretty much never ignite.

Of course an ESC can still catch fire, just like any electrical wiring when shorted, but thats the equivalent of a striking a match, whereas a large lipo battery would be more comparable to a small flamethrower. I guess either can start a fire, as happened here apparently, but its nowhere near the same risk.

 

[eroeder]

Thank you very much for the information as to the cause and what happened when they got to the crash site.

When I got out of my car in the parking lot, the smoke was from an area maybe 15 ft in diameter. When I started walking towards that end of the park, I could see flames, and the two had just gotten past the fence.



I can sympathize, when I saw them leave, I had very mixed emotions. At that point, my thoughts were:

"what would I do?" Would I leave, or would I stay.

I have this attitude that accidents happen and police and fire departments 'protect and serve'. This was an accident. No one got hurt, some dry grass got burned. No big deal (in this case). A total of 4 fire engines (two in the park and two on the highway) fought the fire. Another 4 (or more) fire engines arrived and stood by. A half dozen police units showed up (and did nothing but stand around). One crime scene investigator interviewed everyone who saw the beginning of the event. Names were taken. No one knew who the individuals were.

I've heard stories of municipalities fining those responsible for the 'cost' of the effort to put out the fire.

Had the fire department deployed a drone as soon as the call came in and accessed what was happening, the response would have been much more efficient. If a Cal Fire Unit had been called in, they could have driven onto the 'wetland' and put the fire out in minutes, instead of the hour or so it took. The Sunnyvale fire units had to drag hoses through a fence and around 15 acres of brush. hmmm.

So, to my way of thinking, there is no 'cost', this is what the fire department is for, and their response was professional and measured, but it could have been so much more efficient.

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Wow, if that is a true account, it exemplifies the issue nowadays; nobody takes responsibility for their own actions/mistakes. Yes it appears an accident, but then they apparently left the scene, knowingly left the scene, surely afraid of the consequences of talking to the fire deportment. Definitely fineable now.

If we do not police our own hobby and act responsibly, the FAA will impose more rules and bans. The ENTIRE hobby suffers!

 

[JohnC]

If we do not police our own hobby and act responsibly, the FAA will impose more rules and bans. The ENTIRE hobby suffers!

So that is one of the reasons I put up this thread. As soon as the fire flared up, most of the RC enthusiasts landed their models and there was almost a collective attitude of:

Oh No! this could lead to us being banned from the park!

It would be a good idea to keep a low profile.

The concern is not the FAA, the concern is the image this creates in the general public.

---------------------------------------

This was 'just' a brush file in a nature preserve. It does highlight the risk of LiPos and other electronics. How well educated are all of us to dangers of the models we build and fly? There are so many being drawn to 'drones', which use multiple ESCs. How many of us know how to size them properly, and choose and maintain their LiPo Batteries to reduce risk? There are a lot of fantastic videos out there on the subject. But as easy as the equations are, it's still math, and not many of us are keen on math.

___________________________________

I'm about to head back there this morning, hopefully to fly, but also to understand the reaction of the many flyers I'm told go there on Sunday Mornings.

 

[RAM]

I'm about to head back there this morning, hopefully to fly, but also to understand the reaction of the many flyers I'm told go there on Sunday Mornings.

I'm not a local so I don't know the area but if I had just seen a brush fire caused by the same components I'm about to use, I might find a less combustible place to fly..

 

[gooniac33]

Let's just make this clear. Anything that you do now days is dangerous. The battery in your car has much more energy than anyone ever cares to realize. Starters take anywhere from 300-800amps to start your car. Yes you read that right... And diesels take even more energy! If you short out your car battery it will explode and cause a fire which is why you will occasionally see a car fire as a result of an accident on the freeway. And when that happens what do you do? See that there is a fire and just walk away because you are scared???? I really hope not because that is a crime since you are leaving the scene of an accident. This fire may not seem like that big of a deal and had the person that started it stayed to tell their account of what happened then things would be different. However when you leave the scene of an accident you are going to be perused by the authorities. I urge the person that started this fire to fess up to the authorities and let them know what happened so that there is no fall out for the rest of the responsible RC pilots at Baylands. I have been flying there since 2008 and have had a hand full of crashes that resulted in me making the walk of shame. The first thing that you do is unplug the battery and make sure that it is not shorted out. Secondly you pick up all of the pieces that were associated with the crash and take them away from the area. If you have a damaged lipo then you have to spend all of your time making sure that it is contained and if possible get it to the BBQ area and leave it in the BBQ pit where it will away from all ignition sources. These are all basic rules of thumb that any one of the locals could have helped with had this person actually stopped and talked to someone...

One thing that really irritates me about situations like this is that the people who show up and do the wrong thing will actually mess it up for the people that have been there forever and always done the right thing. We all are here to help and had I been there I would have helped this person deal with the situation... The last thing that we need is attention like this due to someone being afraid to fess up to their own actions...

 

[nerdnic]

Were you there today?

I'll be there tomorrow, Sunday morning.

Unfortunately I won't be able to make it out this weekend.

This is pretty bad though. If they shut down Baylands for RC flying because of this there really arent any alternative fields we can all go to. This will end the hobby for many pilots in this area.

 

[piccolo831]

See that there is a fire and just walk away because you are scared???? I really hope not because that is a crime since you are leaving the scene of an accident. This fire may not seem like that big of a deal and had the person that started it stayed to tell their account of what happened then things would be different. However when you leave the scene of an accident you are going to be perused by the authorities. I urge the person that started this fire to fess up to the authorities and let them know what happened so that there is no fall out for the rest of the responsible RC pilots at Baylands.

One thing that really irritates me about situations like this is that the people who show up and do the wrong thing will actually mess it up for the people that have been there forever and always done the right thing. We all are here to help and had I been there I would have helped this person deal with the situation... The last thing that we need is attention like this due to someone being afraid to fess up to their own actions...

I agree here. The person(s) responsible need to acknowledge their fault and be held accountable. If Multirotorflyer knows who these people are, you should insist that they contact the authorities and let them know who they are. The news will have a field day with the idea that a "DRONE" caused a wildfire. Just image the repercussions to such a headline. We are hobbyists need to hold others accountable so that mis-representation is not the NORM here. Nameless "DRONE" pilots who do not know how to properly handle situations and/or make bad decisions, will cause more senseless regulations and restrictions on an industry and hobby already under scrutiny. Multirotorflyer, if you indeed are close to these pilots, please have them do the right thing in this situation. Take ownership of what has happened here and nip this now before it become a bigger issue.

Please also be aware, I believe descriptions of the people and video of the incident (from a quad after the crash) are being reviewed now and will/have been provided to the authorities. So it will be far better for them to turn themselves in than be investigated by the authorities. Don't make this incident be the reason the use to shut us out of the park...

 

[RAM]

Is there anything you local guys can do to help restore the area?

 

[piccolo831]

Is there anything you local guys can do to help restore the area?

Its a nature preserve. Its illegal for us to do anything since its a protected wetland... Which makes it harder for us to explain why we are flying over it...

 

[JohnC]

I'm not a local so I don't know the area but if I had just seen a brush fire caused by the same components I'm about to use, I might find a less combustible place to fly..

The vast majority of the flyers fly over the green grass shown in the photo.

I did go back today, and I flew. It was amazing to fly at a place where I could land on a flat, grassy field. I was annoyed by the multitude of bugs in the grass though.

Typically, it's a small portion of the multi-rotor pilots that fly over the 'combustible', bone dry preserve next to the grassy field.

----------------

UPDATE: Based on the video (see later in the thread), the ignition point was a bit further to the north, and the extent a bit larger than I show it in the photo. The video was taken (by the way) by an RC Plane, not a multi-rotor. There was a quad copter that overflew the fire later when it was much bigger.