Crashed dji air 3s

[Flysomerset]

Hello all.
Reagan here.
Basically just crashed my dji air 3s.
flight log attached. some one will be able to read better than me.
i worked my way up to this drone.
Mini 2 - mini 3 pro then this. still a bit a jump. saving up over time
I have the fly more combo with rc 2
Activated 15 days ago. now this..
could some break down the crash for me

 

[Meta4]

could some break down the crash for me

The flight ended badly after only 7 seconds.
You were impatient and didn't wait for GPS and flew in atti mode, but that had nothing to do with the incident.
You launched and started by flying forwards while climbing and rotating anti-clockwise.
At 6.2 seconds things came unstuck and the drone rolled over and tumbled to earth.
It's not clear what caused this.
If it was loss of a prop or motor, the drone would have spiralled down rather than tumbling.

 

[BudWalker]

Hello all.
Reagan here.
Basically just crashed my dji air 3s.
flight log attached. some one will be able to read better than me.
i worked my way up to this drone.
Mini 2 - mini 3 pro then this. still a bit a jump. saving up over time
I have the fly more combo with rc 2
Activated 15 days ago. now this..
could some break down the crash for me

Ouch! Looks to me like the right back motor/prop lost propulsion. Either prop or motor loss. At time 5.7 secs the Air 3s begins to rotate in all 3 axes: pitching up, rolling CW and rotating CW about the Z axis (yaw). This is consistent with right back motor/prop lost propulsion.

Also plotted is the height which shows the Air 3S beginning to descend after the tumbling starts.

IMHO the propulsion loss looks to be total. If it were a partial loss (e.g. partial prop loss or intermittent motor) it's possible the Air 3S would spin and not tumble it's way to the ground. With a partial loss the Air 3S might manage to stay close to level. But, the loss of angular momentum in the right back motor/prop will cause CW rotation about the Z axis.

Was the right back prop intact?

 

[Flysomerset]

Hello. One side of the drone all prop were very much chewed up. The drone was stuck in a tree too. I not sure if caused by the tree would make sense as that was not is the side that was hanging from the tree

 

[Flysomerset]

Here a photo of a 2 broken propellers
See one still.with tips.
I think could be this.
Also would it make span down to the tree.

 

[Meta4]

Here a photo of a 2 broken propellers
See one still.with tips.
I think could be this.
Also would it make span down to the tree.

That's relatively minor damage which wouldn't cause the drone to tumble from the air.
It couldn't have happened in clear air and must have been a result of crashing into a tree.

Did you see the drone when it crashed?
Was it in clear air or did you fly into a tree?

 

[Flysomerset]

Hello. No. I didn't. I was juat setting out ok a walk. I didn't see it.
Obstacle avoidance systems were on. Was i just putting to much faith in them

 

[Meta4]

Hello. No. I didn't. I was juat setting out ok a walk. I didn't see it.
Obstacle avoidance systems were on. Was i just putting to much faith in them

So you might have just flown into a tree without looking where the drone was going?

 

[Flysomerset]

No. Basically I took i up.and took it to 10m anticipating to fly over the tree as I walked under it. Whilst looking at the screen controller.
The sun was blinding couldn't see the screen.
I have done this lots but. I font know

 

[Flysomerset]

Basically as the sun blinded me i crashed. But to get to the position it landed into the tree I must of gown through the top

 

[careless]

If you were impatient and didn't wait for GPS the wind could have pushed the drone into the tree.

 

[BudWalker]

I can appreciate the conclusion that the Air 3S was flown into the tree. From the description the Air 3S was launched without sufficient GPS, no visual contact, etc. The props shown appear to have had the tips worn off - just what would be expected from being caught in a tree.

But I'm still going to with propulsion loss causing the Air 3S to descend into the tree. The incident started around 5.8 secs when the horizontal velocity was 1.2 m/s in a north easterly direction. For the next 1.6 secs the speed and direction varied somewhat but, on average, remained constant. If the Air 3S had flown into the tree I would expect the horizontal velocity to abruptly drop to near 0.0 m/s.

Also note that the message "Motor unable to rotate. Check for objects blocking motor..." happened at 7.0 secs - 1.2 secs after incident start.

The red plot shows the horizontal speed. The north easterly direction is indicated by north and east speeds being roughly equal.

 

[MS Coast]

I can appreciate the conclusion that the Air 3S was flown into the tree. From the description the Air 3S was launched without sufficient GPS, no visual contact, etc. The props shown appear to have had the tips worn off - just what would be expected from being caught in a tree.

But I'm still going to with propulsion loss causing the Air 3S to descend into the tree. The incident started around 5.8 secs when the horizontal velocity was 1.2 m/s in a north easterly direction. For the next 1.6 secs the speed and direction varied somewhat but, on average, remained constant. If the Air 3S had flown into the tree I would expect the horizontal velocity to abruptly drop to near 0.0 m/s.

Also note that the message "Motor unable to rotate. Check for objects blocking motor..." happened at 7.0 secs - 1.2 secs after incident start.
View attachment 184263
The red plot shows the horizontal speed. The north easterly direction is indicated by north and east speeds being roughly equal.

Drones flown into tree canopies won't always come to a sudden stop. They slow and bounce around as they contact the flexible outer leaves and small branches. The velocity variations you show make sense for flying into a tree canopy.

 

[Flysomerset]

Hello. Thanks for that. The drone was above the tree. As it was right at the top.

 

[BudWalker]

Drones flown into tree canopies won't always come to a sudden stop. They slow and bounce around as they contact the flexible outer leaves and small branches. The velocity variations you show make sense for flying into a tree canopy.

True enough. But, the Air 3S didn't, on average, slow down any. The velocity variations are what is normally seen with the tumbling. Also note that obstacle avoidance was enabled but isAvoidingObstacle is False.

I'm still going with, just barely, that the cause was propulsion loss not being flown into the tree. Too bad the .DAT file is encrypted.

 

[Meta4]

But I'm still going to with propulsion loss causing the Air 3S to descend into the tree.

Given that the OP:

• gave no description of the incident
• later confused and evasive replies to questions
• that he launched very close to a tree
• and within 7 seconds ended up in a tree without seeing the incident

I believe that the drone was flown straight into the tree without any failure on the drone's part.

 

[BudWalker]

Given that the OP:

• gave no description of the incident
• later confused and evasive replies to questions
• that he launched very close to a tree
• and within 7 seconds ended up in a tree without seeing the incident

I believe that the drone was flown straight into the tree without any failure on the drone's part.

I prefer to base my analysis on numbers. To that end I was able to integrate the horizontal speed to determine the Air 3S travelled 4.6 meters before it started tumbling and then an additional 1.1 meters before the recording stopped. The Air 3S achieved a height of 13.9 meters and started to drop after the tumbling started. I wouldn't call that very close to the tree. The OP claims he has done this particular maneuver "lots".

Evasive? Really?!?! Maybe he hasn't had a lot of experience explaining incidents like this.

 

[MS Coast]

the Air 3S travelled 4.6 meters before it started tumbling and then an additional 1.1 meters before the recording stopped. The Air 3S achieved a height of 13.9 meters and started to drop after the tumbling started. I wouldn't call that very close to the tree.

Not being argumentative here. Just curious. How does that rule out a collision with a tree? Given that the drone came to rest in a tree, it's plausible that it hit a branch tip, began to tumble. dropped, and became lodged in the tree with the props blocked. Is the location of the tree with respect to the takeoff point known?

 

[Meta4]

The idea that the drone had a catastrophic propulsion failure less than a second before striking a tree the flyer couldn't see is an amazing coincidence.
Launching close to a large tree, full throttle, elevator and rudder, without GPS and being able to see the drone or the screen view is a recipe for crashing.

 

[BudWalker]

Is it possible the Air 3S came close to the tree, managed to pick up

Not being argumentative here. Just curious. How does that rule out a collision with a tree? Given that the drone came to rest in a tree, it's plausible that it hit a branch tip, began to tumble. dropped, and became lodged in the tree with the props blocked. Is the location of the tree with respect to the takeoff point known?

You're right. The point was that the Air 3S wasn't launched that close to the where the incident occurred.

The tumbling that began at 5.85 secs is orderly in the sense that rotation is about all 3 axes. The horizontal speed and direction are maintained and the descent is smooth. It doesn't look like the Air 3S was hung up and thrashing about.

@Flysomerset can you check that the right back motor rotates smoothly?