Get more from your Mavic
The largest Mavic community in the world
Join Us Now

Mavic Air 2s crashed while trying to launch off balcony

hasanjafri

New Member
Joined
May 16, 2021
Messages
4
Reactions
2
Age
25
Location
Canada
Hey guys,

I'm a new Mavic drone pilot but have a few trips now under my belt.

Today I tried to launch my Air 2S from my friend's balcony (17th story) which I've done several times before.
Every other time, it would rise slowly and I'd change direction and fly it out carefully.

Today, however, as it begun to lift off (keep in mind it was in Cine mode so all the sensors and obstacle detection was enabled and had propeller guards attached) I tried to move it a bit to the left before rotating it to exit the balcony facing front and I don't know how it gathered so much speed, it first hit the wall to the left (opposite to the exit) at which point I released all control over my joystick to move and then it automatically tried to regain it's composure and immediately crashed into the wall in the back and fell to its demise. Thankfully nobody or any cars were around or it could have been bad but the drone was completely shattered.

I don't understand what went wrong? I've done this several times and it went very smoothly even if the drone lost signal on the way, it would RTH and I could manually maneuver it inside my own balcony. I was NOT in Sport mode but Cine mode so all the sensors + obstacle detection was on, I also had propeller guards attached.

Thankfully I have DJI Care so this should be covered as part of accidental/collision damage right?

Can someone please explain what went wrong here? Or was it an outlier incident that could be a potentially new error on the Air 2s?
 

Meta4

Well-Known Member
Joined
Oct 30, 2016
Messages
9,609
Solutions
1
Reactions
11,431
Age
65
I tried to move it a bit to the left before rotating it to exit the balcony facing front and I don't know how it gathered so much speed, it first hit the wall to the left (opposite to the exit) at which point I released all control over my joystick to move and then it automatically tried to regain it's composure and immediately crashed into the wall in the back and fell to its demise.
This explains enough to tell what the problem was, even without data.
Your drone had a yaw error.
Balconies are made of reinforced concrete, which is filled with steel.
When you started up, the compass was close above some of the steel reinforcing which would have deflected the compass
The gyro sensors in the IMU get their initial directional values from the compass, but the compass would have been reading incorrectly because of the steel, so the gyro sensors were initialised incorrectly.

As you climbed away from the steel, the compass would have gone back to normal but the gyros aren't affected by magnetic fields so they were still reading incorrectly.
When you turned the drone, the gyro and compass data disagreed making the drone think it had drifted from its position.
It tried to move back, but with the incorrect gyro data, each move put it further off position.
The rapid acceleration was due to the drone trying to stay still, but unable to because the data it was using was wrong.
I don't understand what went wrong? I've done this several times and it went very smoothly
Launching from reinforced concrete surfaces is asking for trouble.
You can't tell how far from or close to the steel your compass is.
If it's too close that's game over.

Can someone please explain what went wrong here? Or was it an outlier incident that could be a potentially new error on the Air 2s?
Many drones have been lost to yaw errors and quite a few were launched from balconies or other reinforced concrete structures.
 

hasanjafri

New Member
Joined
May 16, 2021
Messages
4
Reactions
2
Age
25
Location
Canada
This explains enough to tell what the problem was, even without data.
Your drone had a yaw error.
Balconies are made of reinforced concrete, which is filled with steel.
When you started up, the compass was close above some of the steel reinforcing which would have deflected the compass
The gyro sensors in the IMU get their initial directional values from the compass, but the compass would have been reading incorrectly because of the steel, so the gyro sensors were initialised incorrectly.

As you climbed away from the steel, the compass would have gone back to normal but the gyros aren't affected by magnetic fields so they were still reading incorrectly.
When you turned the drone, the gyro and compass data disagreed making the drone think it had drifted from its position.
It tried to move back, but with the incorrect gyro data, each move put it further off position.
The rapid acceleration was due to the drone trying to stay still, but unable to because the data it was using was wrong.

Launching from reinforced concrete surfaces is asking for trouble.
You can't tell how far from or close to the steel your compass is.
If it's too close that's game over.


Many drones have been lost to yaw errors and quite a few were launched from balconies or other reinforced concrete structures.
Thank you so much for the detailed explanation, I really appreciate it. It will help a lot when explaining this issue to a support rep for my warranty.

I will be extra careful with balcony launches (if I ever do any in the future). But regardless, this should be covered and I can get a device replacement if I have DJI care right?
 
  • Like
Reactions: Zeke and tlswift58

Meta4

Well-Known Member
Joined
Oct 30, 2016
Messages
9,609
Solutions
1
Reactions
11,431
Age
65
I will be extra careful with balcony launches (if I ever do any in the future).
If you were to launch there or a similar location in future, keep the drone well above the concrete, on a plastic or wooded box etc.
Try to get the drone 0.5 metres or more above the deck.
You can check that the compass isn't affected by nearby steel by checking the drone icon in the map window and confirming that it is pointing the same compass direction as the actual drone/
ie. Drone facing east .. drone icon also facing east.
But regardless, this should be covered and I can get a device replacement if I have DJI care right?
I think so.
 

hasanjafri

New Member
Joined
May 16, 2021
Messages
4
Reactions
2
Age
25
Location
Canada
If you were to launch there or a similar location in future, keep the drone well above the concrete, on a plastic or wooded box etc.
Try to get the drone 0.5 metres or more above the deck.
You can check that the compass isn't affected by nearby steel by checking the drone icon in the map window and confirming that it is pointing the same compass direction as the actual drone/
ie. Drone facing east .. drone icon also facing east.

I think so.
Thank you so much for your help!
 

MAvic_South_Oz

Well-Known Member
Joined
May 25, 2017
Messages
5,678
Reactions
4,633
Age
59
Location
South Australia, the great southern land
It will help a lot when explaining this issue to a support rep for my warranty.

this should be covered and I can get a device replacement if I have DJI care right?

Normal warranty would most likely be denied, as they regards this as pilot error (it is of course).
They might give you a small discount on a new drone if they are feeling generous, and how they are approached.

If you have Care Refresh, then yes, even this situation will be covered, provided you pay the first claim amount as they set for your country, not sure what that is.

I'd still post your flight logs (TXT and DAT if you can find that too), as it can totally confirm what happened.
Then you (and others) can use that for avoiding this in the future . . . info on how here . . .


It's good to read through sometime to understand the info etc, but to get the info needed, see section 3.
 

cgmaxed

Well-Known Member
Joined
Aug 2, 2020
Messages
1,033
Reactions
766
Age
50
Location
Naples, FL
Hey guys,

I'm a new Mavic drone pilot but have a few trips now under my belt.

Today I tried to launch my Air 2S from my friend's balcony (17th story) which I've done several times before.
Every other time, it would rise slowly and I'd change direction and fly it out carefully.

Today, however, as it begun to lift off (keep in mind it was in Cine mode so all the sensors and obstacle detection was enabled and had propeller guards attached) I tried to move it a bit to the left before rotating it to exit the balcony facing front and I don't know how it gathered so much speed, it first hit the wall to the left (opposite to the exit) at which point I released all control over my joystick to move and then it automatically tried to regain it's composure and immediately crashed into the wall in the back and fell to its demise. Thankfully nobody or any cars were around or it could have been bad but the drone was completely shattered.

I don't understand what went wrong? I've done this several times and it went very smoothly even if the drone lost signal on the way, it would RTH and I could manually maneuver it inside my own balcony. I was NOT in Sport mode but Cine mode so all the sensors + obstacle detection was on, I also had propeller guards attached.

Thankfully I have DJI Care so this should be covered as part of accidental/collision damage right?

Can someone please explain what went wrong here? Or was it an outlier incident that could be a potentially new error on the Air 2s?
I noticed this type of drone movement on my balcony as well. After a few scares, I realised that the sensors were causing it to try and avoid other parts of the balcony, while ignoring other parts, so it would fly into the wall or railing. Now, whenever I take off from a balcony, I go to sport mode, so the sensors are off. I've never had a problem since then. The drones always lifts off straight with no sensors on. But with senors? I'm never gonna do that again. P.S. My balcony is made of wood, so it not a compass problem, at least for me. The sensors just created havoc in the little drones brain.
 

Meta4

Well-Known Member
Joined
Oct 30, 2016
Messages
9,609
Solutions
1
Reactions
11,431
Age
65
I noticed this type of drone movement on my balcony as well. After a few scares, I realised that the sensors were causing it to try and avoid other parts of the balcony, while ignoring other parts, so it would fly into the wall or railing.
The OP's issue had nothing to do with obstacle avoidance sensors.
Any movement cause by OA would be relatively gentle rather than the violent acelleration noted by the OP.

P.S. My balcony is made of wood, so it not a compass problem, at least for me.
As long as you don't place the drone just above a steel bolt.
 

cgmaxed

Well-Known Member
Joined
Aug 2, 2020
Messages
1,033
Reactions
766
Age
50
Location
Naples, FL
The OP's issue had nothing to do with obstacle avoidance sensors.
Any movement cause by OA would be relatively gentle rather than the violent acelleration noted by the OP.


As long as you don't place the drone just above a steel bolt.
I here ya. I'll keep it above the railing during launch. Landing is sometimes problematic when I land on the balcony floor though. The drone or drones will often drift toward the wall or the railing. This is with the sensors off. The balcony extends 4 ft away from the wall of the house. It's a tight fit.
 

EricJT

Well-Known Member
Joined
Apr 20, 2019
Messages
383
Reactions
294
Location
Toronto ON
Launching from reinforced concrete surfaces is asking for trouble.
You can't tell how far from or close to the steel your compass is.
If it's too close that's game over.
I think I know the answer to my question but just want to make sure.....what about landing on surfaces that may have steel?

I think that since the AC's compass, IMU and FC were fine when taking off from a non-steel surface, then landing on a steel surface later should be fine. Correct?
 

Meta4

Well-Known Member
Joined
Oct 30, 2016
Messages
9,609
Solutions
1
Reactions
11,431
Age
65
I think I know the answer to my question but just want to make sure.....what about landing on surfaces that may have steel?
You would have a different problem to deal with.
As the drone gets close to the steel and starts to affect the compass, the drone will "lose its sense of direction" and wander around.
It's best not to launch or land on surfaces where steel can affect your compass.
 

EricJT

Well-Known Member
Joined
Apr 20, 2019
Messages
383
Reactions
294
Location
Toronto ON
You would have a different problem to deal with.
As the drone gets close to the steel and starts to affect the compass, the drone will "lose its sense of direction" and wander around.
It's best not to launch or land on surfaces where steel can affect your compass.
Thanks for your reply....thinking I knew the answer to my own question may have proven regrettable. That is why I turned to you for the accurate answer.

The good news is that I always follow the non-steel rule for both takeoffs and landings. Better safe than sorry.
 

tlswift58

Well-Known Member
Joined
Nov 6, 2020
Messages
1,114
Reactions
955
Age
63
Location
Franklin, NC
Thank you so much for the detailed explanation, I really appreciate it. It will help a lot when explaining this issue to a support rep for my warranty.

I will be extra careful with balcony launches (if I ever do any in the future). But regardless, this should be covered and I can get a device replacement if I have DJI care right?
Was the railing metal as well. As others have stated - a lot of metal causes issues. Most people would have the drone in hand out past the railing and then launch from there - if you are inclined to try it again from a balcony.

As for Refresh - a big maybe on DJI's part - as they will have the flight data to say yes or no on pilot error (probably) or drone issue and replace under Refresh.
 

MAvic_South_Oz

Well-Known Member
Joined
May 25, 2017
Messages
5,678
Reactions
4,633
Age
59
Location
South Australia, the great southern land
As for Refresh - a big maybe on DJI's part - as they will have the flight data to say yes or no on pilot error (probably) or drone issue and replace under Refresh.

I have never taken out Care Refresh, but as long as you have the 'body', it covers literally anything, including pilot error, or bad flying, or careless flying . . . possibly not criminal or terrorist activity though.
 
  • Like
Reactions: tlswift58

tlswift58

Well-Known Member
Joined
Nov 6, 2020
Messages
1,114
Reactions
955
Age
63
Location
Franklin, NC
I have never taken out Care Refresh, but as long as you have the 'body', it covers literally anything, including pilot error, or bad flying, or careless flying . . . possibly not criminal or terrorist activity though.
That will remain to be seen when they process the claim. Hoping DJI does, but not holding my breath.

3rd Party Insurance seems to be a far better and many times cheaper option than dealing with DJI. Instead of "Refresh" I'd suggest people at a minimum call insurance companies to "compare" coverage - not to mention probably getting much faster service thru insurance than DJI. My one and only experience with DJI (USA) was not a good one and took forever for them to work it.
 
  • Like
Reactions: MAvic_South_Oz

slup

Well-Known Member
Joined
Oct 18, 2019
Messages
2,797
Reactions
7,241
Age
53
Location
Sweden
...I always follow the non-steel rule for both takeoffs and landings. Better safe than sorry.
Yeah ... that's good, but a yaw error isn't created at "take-off".

When you power on your drone the IMU know nothing about the cardinal directions & how the craft is pointing in relation to those ... and it's the IMU that's primarily used airborne, not the compass.

A yaw error is created in the moment when you power on your craft ... in that moment the compass will tell the IMU the cardinal directions. If the compass is deflected in that moment the IMU will be wrongly initialized & cause it to believe that the craft is pointing in another direction than the correct one. The compass will quickly be corrected once leaving the disturbed area ... but the IMU will remain wrong.

So if you accidentally power on your craft too near magnetic interference ... & then put it down for take off far away from magnetic objects the damage is already done.

Then regarding landings ... or general flying near or in a magnetic disturbed area. It's correct that the compass will slooowly feed in corrections to the IMU over time, so leaving the craft in magnetic disturbance will eventually cause problems but it will take time, both due to that you rarely are that near magnetic objects during flight (like a drone foot/leg distance from it) & due to that the compass isn't the only one that feed in corrections to the IMU, both the gyro & the VIO sensor (a turning measurement created from the bottom VPS sensor) does that also. I wouldn't be particular afraid of magnetic disturbance induced problems neither during flight or during normal landings.

Power on your craft in your out stretched hand (no watches, bracelets or rings near that hand) ... then your craft is around 1,5m above ground & away from your body/clothes with perhaps zippers & buckles. Once the live view have been activated in the app the IMU have been properly initialized. After that you can place it on ground for take off. Before getting airborne you ALWAYS check the drone icon on the map in the app & confirm that it's pointing equal to the map objects (roads, houses etc.) as the craft does in reality.

Do this & you have massively minimized the risk for a yaw error ...
 

HobWash

New Member
Joined
Jun 6, 2021
Messages
4
Reactions
13
Location
San Francisco, CA
Hi All -- I'm new here -- not sure I'll be much help, but I noticed something funny that might be related.

When I override the default controls speed (gimbal pitch/ya/etc) they don't always save.
I learned this the hard way, I had everything set to full speed just to try it out. Then I turned it back to something reasonable and saved it, tested it to make sure it was good, then shut the drone down.

Later when I powered on, the controls reverted to ultra-scary-fast and I almost mowed down a tree.
I now always second-guess & double-check the controls before I begin flight.
 
Lycus Tech Mavic Air 2 Case

DJI Drone Deals

1. Mini SE - $299
2. Mini 2 - $449
3. Air 2 (renewed) - $649
4. Air 2s - $999
5. FPV Combo - $1299
6. Mavic 2 Zoom - $1349
7. Mavic 2 Pro - $1499

New Threads

Forum statistics

Threads
107,148
Messages
1,269,274
Members
138,332
Latest member
Aztecking