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Crash, unable to cancel ATTI
864 28 2018-3-3
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demeeb
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Dear fellow flyers,
Unfortunately my Mavic Air crashed today.
Although I would consider myself as a beginner-pilot I have still doubts about the reason why it crashed and would be happy to hear your thoughts.
I was flying indoors at a height of 2 meter in a area with up to 6 meters height.
As the battery was turning low the ATTI was automated. I always cancel the ATTI as I want to land it myself. At this moment the DJI4app/Mavic Air did not respond, I tried multiple times ticking the red button on the screen but it did not respond.
The ATTI ascended the aircraft (as expected) and I was unable to avoid that. Finally it hit the ceiling and crashed on the floor after falling down.
I have attached the Flightrecord.
Any thoughts??
Thanks


Flightrecord

Flightrecord
2018-3-3
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A CW
Captain
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You can not cancel ATTI mode - it switches to it automatically when GPS and OPTI is disengaged. You won't receive enough satellites flying indoors to get a strong GPS connection and when the drone lost downward vision is selected ATTI mode. Or do you mean return to home rather than Attitude flight mode (ATTI)?
2018-3-3
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Blizzard
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Spain
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If you fly indoor, disable the Return to Home!
Otherwise it will ascend to the height you have set and crash into the ceiling!
2018-3-3
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demeeb
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Sorry, wrong terminology from my side...
I mean: Automated RTH. I was not able to cancel the automated RTH. It did not respond to abort RTH.
2018-3-3
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A CW
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demeeb Posted at 2018-3-3 12:09
Sorry, wrong terminology from my side...
I mean: Automated RTH. I was not able to cancel the automated RTH. It did not respond to abort RTH.

I see - you need a GPS connection and home point set on the map for RTH to work effectively.
2018-3-3
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fansf77370fb
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You can’t just fly indoors like you do outside you need to go into your main settings and make changes. As I’m sure you already know the hard way. This is why it is very important to remove your rise yourself with all the settings.
2018-3-3
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demeeb
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A CW Posted at 2018-3-3 12:12
I see - you need a GPS connection and home point set on the map for RTH to work effectively.

Agreed.
My question is : Can there be a reason why automated RTH can NOT be cancelled?
2018-3-3
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A CW
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demeeb Posted at 2018-3-3 12:17
Agreed.
My question is : Can there be a reason why automated RTH can NOT be cancelled?

It can - when you're not in ATTI mode.
2018-3-3
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demeeb
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fansf77370fb Posted at 2018-3-3 12:14
You can’t just fly indoors like you do outside you need to go into your main settings and make changes. As I’m sure you already know the hard way. This is why it is very important to remove your rise yourself with all the settings.

I was unable to cancel the RTH (which automated as a result of low battery)
Is there a setting which prevents such? I am familiar with the different RTH altitudes but have not found a setting which disables the RTH in all.
2018-3-3
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demeeb
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A CW Posted at 2018-3-3 12:18
It can - when you're not in ATTI mode.

So if I understand:
-  ATTI mode can not be disabled (when GPS is not available)
-  In ATTI mode you can not cancel an (low-battery) automated RTH
Is that correct?
Thanks
2018-3-3
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A CW
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ATTI can not be disabled or enabled manually under any circumstances. It moves in and out of that mode automatically subject to GPS/GLONASS receivers and the optical flow via VPS being effective or not - subject to sufficient lighting and surface patterns.

When in ATTI mode RTH won’t work as the drone is basically disorientated from its position in relation to it’s take off point. Only the barometer works. If you read the manual it advises to land immediately when you engage ATTI mode and not to take off before a home point is set on the map. With no home point set, no GPS connection and no optical flow, flying indoors on a low battery in ATTI mode with failsafe set to RTH you were just waiting to crash. Cancelling RTH will stop the RTH sequence but as you were in ATTI the drone would still fly erratically and loves walls and ceilings in that mode. You should only fly indoors with prop guards on and when you know everything about the app and flight controls of the drone. I’ve flown over a thousand times over the years with several DJI drones and still don’t fly indoors!
2018-3-3
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ghostrdr
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How can you RTH indoors? You never had a GPS lock on homepoint.
2018-3-3
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demeeb
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ghostrdr Posted at 2018-3-3 13:27
How can you RTH indoors? You never had a GPS lock on homepoint.

I did'nt. The automated RTH activated as you can read above.
2018-3-3
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demeeb
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A CW Posted at 2018-3-3 13:27
ATTI can not be disabled or enabled manually under any circumstances. It moves in and out of that mode automatically subject to GPS/GLONASS receivers and the optical flow via VPS being effective or not - subject to sufficient lighting and surface patterns.

When in ATTI mode RTH won’t work as the drone is basically disorientated from its position in relation to it’s take off point. Only the barometer works. If you read the manual it advises to land immediately when you engage ATTI mode and not to take off before a home point is set on the map. With no home point set, no GPS connection and no optical flow, flying indoors on a low battery in ATTI mode with failsafe set to RTH you were just waiting to crash. Cancelling RTH will stop the RTH sequence but as you were in ATTI the drone would still fly erratically and loves walls and ceilings in that mode. You should only fly indoors with prop guards on and when you know everything about the app and flight controls of the drone. I’ve flown over a thousand times over the years with several DJI drones and still don’t fly indoors!

Thank you for your helpful explanation. It makes sense.

However I checked the FlightRecord again and discovered GPS mode was still active at the time of the first hit (logged motor obstruction). the ATTI-mode was activated 4 seconds later.....
Which leaves me with the question why RTH (low battery action) in GPS-mode could not be cancelled.
2018-3-3
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A CW
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In that case your best bet is to return the drone to DJI by raising a ticket with DJI support and their engineers will run a full diagnostic evaluation for you. If deemed pilot error you will have to pay for the repair if you don’t have DJI’s care refresh otherwise, it will be covered under warranty. Looking at your data the switch from go home to ATTI is 0.01 of a second and you had 10 satellites when go home activated - this is a low number giving weak GPS. By the time you pressed cancel RTH the drone was already flying around the room in ATTI mode.  
2018-3-3
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demeeb
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A CW Posted at 2018-3-3 14:20
In that case your best bet is to return the drone to DJI by raising a ticket with DJI support and their engineers will run a full diagnostic evaluation for you. If deemed pilot error you will have to pay for the repair if you don’t have DJI’s care refresh otherwise, it will be covered under warranty. Looking at your data the switch from go home to ATTI is 0.01 of a second and you had 10 satellites when go home activated - this is a low number giving weak GPS. By the time you pressed cancel RTH the drone was already flying around the room in ATTI mode.

Yes I will send it for repair.
The Data shows ATTI was activated when the aircraft was already on the ground.
During the first (of multiple) hit on the ceiling the aircraft was still on GPS:
2018-3-3
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Wachtberger
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demeeb Posted at 2018-3-3 14:34
Yes I will send it for repair.
The Data shows ATTI was activated when the aircraft was already on the ground.
During the first (of multiple) hit on the ceiling the aircraft was still on GPS:[view_image]

I have nothing to add to what has been explained already but you have not reported yet what the damage is, if any?
2018-3-3
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I don't care anymore
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Blizzard Posted at 2018-3-3 12:02
If you fly indoor, disable the Return to Home!
Otherwise it will ascend to the height you have set and crash into the ceiling!

Is that a 1/3rd F-16 RC in your profile pic? And is it yours?
2018-3-3
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demeeb
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Wachtberger Posted at 2018-3-3 14:42
I have nothing to add to what has been explained already but you have not reported yet what the damage is, if any?

Thanks for asking.
It is damaged. One arm broken, the housing is still one but does not fit totally.
It just does not make sense, not been able to cancel RTH in GPS-mode....
2018-3-3
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Wachtberger
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demeeb Posted at 2018-3-3 14:53
Thanks for asking.
It is damaged. One arm broken, the housing is still one but does not fit totally.
It just does not make sense, not been able to cancel RTH in GPS-mode....

In this case you definitely have to send it in. Just open a support case with DJI and report the circumstances. I am not sure if there was a malfunction, but if yes, it will be a warranty case.
2018-3-3
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SkyBug
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Nobody likes a crash. Hope you’re back in the air soon!
2018-3-3
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Blizzard
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I don't care anymore Posted at 2018-3-3 14:42
Is that a 1/3rd F-16 RC in your profile pic? And is it yours?

No, it was the real Belgian demo F16 that my son was flying from 2015 till october 2017 all over Europe.
2018-3-4
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djiuser_KFJ3ZIPPdigz
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demeeb Posted at 2018-3-3 12:09
Sorry, wrong terminology from my side...
I mean: Automated RTH. I was not able to cancel the automated RTH. It did not respond to abort RTH.

I lost my mavic pro very recently too. I have been flying many times with 20% battery before and have no issue. This time, it forced land by itself. I pressed stop many times and it fails to cancel landing. At the end, I have to find a bush and crash land. I cannot retrieve my aircraft too. Completely panic and depressed experience. Contact DJI and they insisted it was misoperation. But how could the user cannot full control of the aircraft even the battery low. It was 20% and I have plenty of time to come home. If it forces land on highway I would have caused catastrophic disaster by causing accident or kill someone. Again DJI push the responsibility to user. Everything is user fault. Scam company!
2018-3-4
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LoSBoL
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djiuser_KFJ3ZIPPdigz Posted at 2018-3-4 02:58
I lost my mavic pro very recently too. I have been flying many times with 20% battery before and have no issue. This time, it forced land by itself. I pressed stop many times and it fails to cancel landing. At the end, I have to find a bush and crash land. I cannot retrieve my aircraft too. Completely panic and depressed experience. Contact DJI and they insisted it was misoperation. But how could the user cannot full control of the aircraft even the battery low. It was 20% and I have plenty of time to come home. If it forces land on highway I would have caused catastrophic disaster by causing accident or kill someone. Again DJI push the responsibility to user. Everything is user fault. Scam company!

Altough off topic, Ì think your situation could help others in creating some awareness.

The automated landing procedure kicked in at 20% because of your altitude. The craft calculates how long it takes to get down safely, and 10% wasn't going to be enough. If you watch the batterybar you can see that forced landing would kick in sooner.

Here is the link to your topic.
2018-3-4
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I don't care anymore
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Blizzard Posted at 2018-3-4 02:20
No, it was the real Belgian demo F16 that my son was flying from 2015 till october 2017 all over Europe.

That's even cooler.
2018-3-4
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djiuser_NZrrzIl0GvQ3
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Blizzard Posted at 2018-3-4 02:20
No, it was the real Belgian demo F16 that my son was flying from 2015 till october 2017 all over Europe.

I think I saw him in 2016 during an airshow in Jesolo here in Italy, before the "frecce tricolori"..I have many photos of him
2018-3-6
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demeeb
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Update:
Hello guys, as expected DJI rates this crash as a result of a pilot-error. I have no answer why I could not cancel the automated RTH. In case of low battery RTH this might not be an option. Good learning point!
The Air has been send for repair. Costs were euro 140. Suprisingly DJI send me a brand new aircraft!
Will post video soon.
2018-3-18
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QuadKid
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djiuser_KFJ3ZIPPdigz Posted at 2018-3-4 02:58
I lost my mavic pro very recently too. I have been flying many times with 20% battery before and have no issue. This time, it forced land by itself. I pressed stop many times and it fails to cancel landing. At the end, I have to find a bush and crash land. I cannot retrieve my aircraft too. Completely panic and depressed experience. Contact DJI and they insisted it was misoperation. But how could the user cannot full control of the aircraft even the battery low. It was 20% and I have plenty of time to come home. If it forces land on highway I would have caused catastrophic disaster by causing accident or kill someone. Again DJI push the responsibility to user. Everything is user fault. Scam company!

" But how could the user cannot full control of the aircraft even the battery low. It was 20% and I have plenty of time to come home"

DJI has many useful measures and counter measures to unsure safe flight. I agree with you 100% that the PILOT should have ultimate control and be able to override any automated forced landing due to battery level, sure they can warn you visually (Litchi will continue to warn you visually & verbally) about any anomaly situation, but restrict the pilot to act on it is wrong. Funny they have incorporated a CSC  to shut down the motors in an emergency. To me a forced landing @ 20% battery does not constitute an emergency. If this was a US based company lawyers would have a field day suing DJI (lets say a forced landing resulted in the drone landing in a baby carriage with an infant in it) for their software removing the pilot as an integral part of an emergency plan. Seems to me this would be a relative easy software fix for this "Low Battery Forced Landing" issue especially since battery values are seldom dead accurate.
2018-3-18
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demeeb
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And the video of the crash. Thanks for watching!
2018-3-18
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