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Crash while Active Track - Object avoidance failed
5060 32 2016-12-5
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ik8sqi
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Flight distance : 25774 ft
United States
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Today the Mavic hard-crashed while using Active Tracking to follow me on a motorcycle. As can be seen from the video, the Mavic accelerates to catch up to me, but hwile doing so is slowly progressively decreased altitude, exceeded it's max speed for object avoidance, and crashed into a road sign.

The Mavic was set in P mode, not in S mode. This was a total fail of the built-in object avoidance features. The video is here:
https://logsat.app.box.com/s/q0modi976b2g2k30efm5wojgnfparkeh

and the logs are here:
http://www.phantomhelp.com/LogViewer/1ZX7XS5SWAQXWIPJH7EB/


2016-12-5
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ik8sqi
lvl.1
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United States
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For DJI - while preparing the online repair request, I was forced to accept to a $65/hour evaluation fee that I would be charged anyways if I opted not to proceed with the repair. This would apply if the repair was not performed under warranty.

So here is the dilemma. I strongly believe this is a warranty issue, as the advertised object avoidance during automated tracking did not work. If DJI agrees, there there are no problems. If DJI disagrees however, then I am not willing to pay for the $65/hour evaluation charge, as the product was sold with misleading advertising and thus I would be demanding a refund.

How should we proceed...? My support case is CAS-351178-N0P9Z0.
2016-12-5
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fans05e6c58a
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United States
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I watched the video several times looks like the road goes up hill.did you set a specific height for the mavic to stay at also it hit the fence first.
2016-12-5
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Bent Kangaroo
Second Officer
Flight distance : 362510 ft
Australia
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I really dont think that active tracking gives you the pilot, the right not to have any control over your drone in any situation.
This is clearly operator error imo and if you didnt hit the fence/sign, then you would have hit the next set of objects on your uncontrolled flight. Clearly an accident waiting to happen.
Good luck getting a refund after you trash the mavic. Just initiate the repairs and hope DJI have pity on you and accept the bill, i wouldnt.
2016-12-5
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rodpanam
lvl.3
Flight distance : 733504 ft
France
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Bent Kangarroo, i couldn't say better!
Regarding to the highway on the left it could be worse...
2016-12-5
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hallmark007
Captain
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This is not what active tracking was designed for, this is clearly your fault, drone was at max speed it was trying to track you on the bike, you approached stop sign and veered fast to the right, so the drone was trying to track you also OA sensors were facing you , and so drone hit stop sign sideways not front on, and that's why it crashed, I'm afraid this is a no brainer.
2016-12-5
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ik8sqi
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United States
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The road is flat. As can be seen from the video I stopped and was in the process of making a U-turn *before* reaching an area with trees and other obstacles. The short path I took was clear of any obstacles, and the stop sign was below the drone when it took off.

In addition, the manual clearly states on page 19:
ActiveTrack allows you to mark and track a moving object on your mobile device screen. The aircraft will automatically avoid obstacles in its  ight path. No external tracking device is required.
The Mavic Pro can automatically identify and trace bikes and other vehicles, people and animals, and use different tracking strategies for each.



The drone should have never accelerated to a speed that exceeded the max speed over which the obstacle avoidance sensors stop working. As described in the documentation, if the drone is unable to keep up and/or looses sight of the tracked object, it should stop and hover in place, not accelerate past its max speed to catch up. This (pause and hover) was the behavior I had seen and tested during the previous days - when the drone lost track of me it stopped. Not today. This is clearly a drone-issue, not an operator issue. If the drone can't track properly, then do not advertise these features and make them a selling point. Either we can trust the drone to track properly and safely, or we cannot. Black or white. What is the point of having active tracking if we cannot trust the drone to actually avoid obstacles and stop instead of accelerating?

2016-12-5
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hallmark007
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ik8sqi Posted at 2016-12-6 02:48
The road is flat. As can be seen from the video I stopped and was in the process of making a U-turn *before* reaching an area with trees and other obstacles. The short path I took was clear of any obstacles, and the stop sign was below the drone when it took off.

In addition, the manual clearly states on page 19:

You didn't drive straight down the middle of the road you were continually moving to the right, meaning in order for the drone to track you, it has to move further to the right, but is also trying to focus on you it's not facing the stop sign any more, so impossible for OA to work. Drone was breaking because you stoped, this will always cause it to dip slightly.

Why head of so fast if you wanted drone to track you, you took a stupid risk , this is nothing to do with faulty equipment.
2016-12-5
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rick39
Second Officer
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United Kingdom
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I would be devastated if that happened to me, but it wouldn't have done. I wouldn't attempt to do that in a congested urban area at such low level, adjacent to a wrought iron fence, with so many objects in such close proximity and a couple of feet away from what looks like an early warning radar array. It looks like you accelerated pretty hard pulling wheelies in the first three gear changes. Its surprising the Mavic managed to follow you at all, but you can't help but admire its ability to try and keep up by matching your speed.
Sorry to sound harsh, and I genuinely feel sorry for you crashing your drone so early in your ownership and I guess you hate me for writing this, but $1,250 is a lot to gamble with in such a situation.
2016-12-5
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ik8sqi
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United States
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Everyone keeps ignoring the fact that DJI advertises object avoidance and safety in tracking. I have purchased the drone specifically for that purpose, so it could follow us while riding motorcycles. This was not a gamble or a risk - it was my intended purpose for the use of the drone. I did not buy it to fly it and sightsee as some of you do.

This said, if anyone bothered to look at the logs I posted, you would see how the drone accelerated to over 25mph. This exceeded the 22mph limit that DJI documented.

On pg 11:
The aircraft will switch to P-GPS when it is using both GPS and Vision System for stabilization. When the Forward Vision System is enabled and lighting conditions are suffcient, the maximum  flight attitude angle is 16° with a maximum flight speed of 22 mph (36 kph).

On pg 24:
Assisted Braking from Forward Vision System
Powered by the Forward Vision System, the aircraft is able to actively brake when obstacles are detected in front. Forward and Downward Vision Systems work best when lighting is adequate and the obstacle is clearly marked or textured. The aircraft must  fly at no more than 22mph (36kph) to allow suf cient braking distance.


The drone was flying itself, and it decided to exceed the limits imposed by DJI. This disabled OA and caused it to crash. The crash was caused by the drone loosing altitude and hitting a big, bright red stop sign and a big black fence at an angle that makes it appear like a solid wall. This is a manufacturer's defect, not an operator error. I used the drone to do what it was advertised to do - follow a vehicle while avoiding objects. Furthermore, this was not my first test. In the previous days it followed the motorcycle just fine, avoiding obstacles and stopping and hovering as designed when it lost or could not keep up with the bike. Today these features failed and it crashed.

....and for rick39, I do 0-60mph in 3.4sec on that bike. The acceleration in the video is actually very "soft" compared to my normal driving. And a wheelie actually requires a wheel to lift of the road - what you are seeing is simply the travel of the front suspension going up and down during accelerations and decelerations - the front tire never left the surface or the road in the video, there was no "wheelie".
2016-12-5
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Blade Breaker 0
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United States
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Ive done some testing of the obstacle avoidance. It is good but to avoid a stop sign would be asking allot. A fence post I would guess its not going to see it. I know what it says in the manual but really to not test it first is... Well not what I would do.

Good luck with your repair.
2016-12-5
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dotfiles
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United States
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It actually does seem as though (if the log speeds are accurate) that the Mavic was traveling over 22 mph. It either saw the stop sign and tried to slow down but was going too fast and it was too late at that point, or that it was tracking you, started to slow as you slowed down for your turn and the OA did not see the fence/sign at all.
2016-12-5
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CamStevens
Second Officer

United States
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Caveat - Editorializing ahead.

My own opinion on this is that both parties are at fault.  I have been deeply concerned for quite some time that between DJI's marketing and we as operators buying into the "idiot-proof autonomous flying" marketing hype, we are going to have our hobby legislated into oblivion, with people and property getting hurt along the way.  I think DJI VASTLY overhypes the capabilities of the drone (although it is still an incredible piece of tech that I love), and provides too little details on how things work, what the likely failure modes are, and what the recovery methods are.  We as operators too often fail to take our responsibility of operating our aircraft in a safe manner seriously enough.  

Personally, I think of obstacle avoidance as a last line of defense to try and save the drone when I as a pilot have FAILED to properly control my aircraft.  I NEVER want to rely on this capability to operate the craft safely on my behalf.  In a similar fashion, I would NEVER use Active Track to track myself if I was not able to take IMMEDIATE control of the drone.  So taking shots of me hiking (with the controller in my hand) I would be willing to try.  But tracking me riding a motorcycle, NO WAY (once again, my own person opinion here).  

And this is where I think DJI falls short and is negligent and short sighted to the possible future negative repercussions of their marketing message.  Their implicit marketing message is "just take it out of the box and go fly!"  Sure, there are explicit warnings, tutorials videos, a barely sufficient manual, this forum, etc., so DJI is covering itself here, and moreover, I'm willing to concede they are trying hard and have good intentions.  But I would still love to see a more strongly worded "This drone is not a toy.  Operating this drone safely is YOUR responsibility, and you should understand the aircraft thoroughly before attempting to fly" as a giant bold sticker on the drone, not fine print in the getting started guide that users will promptly throw out (just watch the unboxing videos for proof).  The fact that there are multiple postings of "I can't turn the drone on" is sufficient evidence to DJI that people don't read the manual.  Once again, not DJI's fault, but the more they can improve operator understand of the drone, the better things will be for our hobby long term.

With respect to Active Track specifically, I would prefer to see them call out this type of rule: "Active Track should only be used when the operator is able to readily take control of the aircraft."  Even better would be for them to call out "Active Track should be avoided when the operator's hands are not free, such as when riding a bicycle or motorcycle."

The bottom line in my mind is that as operators, we can NEVER delegate the safe operation of our aircraft.  That means we should always be prepared to take immediate control, and is also why I really want to see a manually selectable ATTI mode.

So I feel for this operator.  He purchased the Mavic for a specific purpose.  I just don't think it's suitable nor safe for that purpose.

2016-12-5
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Bent Kangaroo
Second Officer
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Australia
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The manual states that when using active tracking, " Stay clear of obstacles near the flight path "
The flight path that was directly followed is correct which lead the mavic straight into collision because the OP was in line with an object.
Expect the relevant DJI investigators to decide on this case based on data provided.
Good luck OP.
2016-12-6
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Ulf-F
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Germany
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BTW. The STOP sign means you have to stop in front of the sign. You were not a good ideal for your Mavic. If you respected the  traffic regulations the accident would not have happened.
2016-12-6
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AusAir
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Flight distance : 425049 ft
Australia
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I've had active track follow me up to 50km/h which is a long way above obstacle avoidance speeds. That was on a dirt road through an open paddock however with very few obstacles in sight. There's plenty of situations I'd have loved to use active tracking but I simply didn't have the confidence it wouldn't crash. Call me cynical but I tend to like to see how things operate first hand under a variety of situations before I trust them enough to let them loose.

I'm still stunned that so many people take the autonomous features and obstacle avoidance etc for granted and expect them to be a substitute for piloting skills. These features are their to assist in piloting or assist in getting a particular shot. They're not there to replace the pilot entirely no matter how much some might want or expect that.
2016-12-6
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DJI Mindy
Administrator
Flight distance : 7 ft
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Sorry for your crash, ik8sqi.
Since you had contacted our tech support and sent it in.
Our engineers will help to analyse your flight data and let you know what could have caused the issue.
2016-12-6
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Bucefalo
Second Officer
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Italy
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i just want to say one thing man.. WHY ... why did u SPEED up like crazy  pretending that Drone would keep ur boost at start???
and also u keep going on the right in direction of that fence.. and.. WHY u did NOT set altitude higher?? it would avoid sign and fence !
in a urban street anyway i think it could have happened in 10000  other ways! sorry but u took a big risk and indeed few meters later your drone fell down :-(

P.S. anyway the drone hit the fence BEFORE stop sign...
2016-12-6
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hallmark007
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You keep spouting out what it says in the Manual, it's like you even read it twice before you ventured out to fly, but you obviously missed the part in active track, to stay clear of obstacles in active track, obstacle's you where completely surrounded by. You have a very big and fast motorcycle how on earth would you choose to buy a Mavic to try follow that about, I think it's fair to say a bit of common sense, would have avoided this crash..
2016-12-6
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Incredible Aeri
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United States
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This reminds me of the guy that put cruise control on his car and hopped in the back seat and thought nothing would go wrong lol...
2016-12-6
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Chaser720
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ik8sqi Posted at 2016-12-5 23:56
Everyone keeps ignoring the fact that DJI advertises object avoidance and safety in tracking. I have purchased the drone specifically for that purpose, so it could follow us while riding motorcycles. This was not a gamble or a risk - it was my intended purpose for the use of the drone. I did not buy it to fly it and sightsee as some of you do.

This said, if anyone bothered to look at the logs I posted, you would see how the drone accelerated to over 25mph. This exceeded the 22mph limit that DJI documented.

Car companies advertise that air bags will save your life in a crash but I'd rather not try it.
2016-12-6
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boldblue737
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I'm sorry for the crash, that looked painful.
I think it was clear to me that DJI object avoidance was effective for large objects like tree trunks, rock formations and walls. There has been a million examples (and I think DJI warns of it) that things like branches and power lines may not be picked up. For the object avoidance to see the thin flat surface of the fence that is running parallel to the flight track or the tiny surface of the stop sign in time to avoid them is asking too much in 2016 technology. The pilot still bears the burden to protect your drone.

I hope I'm wrong but I doubt very, very much DJI will cover this.


2016-12-6
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damaltor
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Canada
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One thing I don't get, you stated "I have purchased the drone specifically for that purpose, so it could follow us while riding motorcycles". So, did you actually plan to putt around at 22 mph on your bike, having the mavic follow and film you? Can't help but wonder if the OA was turned off, so the mavic could keep up?? Not insinuating anything, just puzzled by this.
2016-12-6
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method007
First Officer
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Why would you do this in such a congested area?  And so low?  And around so many things that could cause interference?
2016-12-6
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fansea1e504f
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boldblue737 Posted at 2016-12-6 23:27
I'm sorry for the crash, that looked painful.
I think it was clear to me that DJI object avoidance was effective for large objects like tree trunks, rock formations and walls. There has been a million examples (and I think DJI warns of it) that things like branches and power lines may not be picked up. For the object avoidance to see the thin flat surface of the fence that is running parallel to the flight track or the tiny surface of the stop sign in time to avoid them is asking too much in 2016 technology. The pilot still bears the burden to protect your drone.

dang that sucks, I'm sorry that happened to you... I completely understand why you would want it to follow you, but that was just not a good area to pick, and the way the front of your bike was lifting a little each shift you were clearly getting on the throttle pretty good lol. Looks like the quick take off and objects in the path arnt a good mix.
2016-12-6
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Alansin
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Mexico
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" im going to push the limits of this mavic thing, because i saw it can follow me, avoid obstacles, so why bother with being safe or having logic, *edited for vulgar content - user has been warned* so im going to fly low, fast, and it should follow me and avoid everything on his way, "

guy flyes drone, crashes, complains about it, dji verify data, decide it was an user error, guy cries in fetal position in shower, saying to himself " but it was adverticed.... it was adverticed"

just a lil humor here.
still cant believe how many accidents would have been avoided with some or lil, logic, safety, and being smart about tecnology. i mean, even the most avant grade automated factory, is being supervised by a human at all (or most ) times.

my 2 cents,  i hope i made you smile. because your video just made me cringe and sick.

thank you, becuase i will learn from your experience and file it into my head in the bin: "What not to do with my mavic"
Thank you

2016-12-6
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7H3dDITZZYsP
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United States
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Did you ensure the Activetrack mode you chose kept the forward collisioning enabled?  One of the modes pops up a message saying avoidance is disabled on your phone.  I think it was the profile mode since the drone flys at an angle it can't sense an object it can't see.
2016-12-6
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ik8sqi
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ik8sqi Posted at 2016-12-5 18:24
For DJI - while preparing the online repair request, I was forced to accept to a $65/hour evaluation fee that I would be charged anyways if I opted not to proceed with the repair. This would apply if the repair was not performed under warranty.

So here is the dilemma. I strongly believe this is a warranty issue, as the advertised object avoidance during automated tracking did not work. If DJI agrees, there there are no problems. If DJI disagrees however, then I am not willing to pay for the $65/hour evaluation charge, as the product was sold with misleading advertising and thus I would be demanding a refund.

As an FYI - DJI was very professional and honored the warranty request immediately upon inspection.

On my end, I had been testing the Active Tracking in various instances starting with walking first, then moving to motorcycle at low speeds to eventually to motorcycle at higher speeds to ensure the Active Tracking would work, and we could use the drone in the real world. In previous tests with speeds > 22mph the drone had correctly stopped and hovered in place.

Eventually on the last test, this obviously failed. Telemetry showed that the drone started at an altitude of 10.5 ft (which seems accurate), but then the altitude reading dropped to 1ft, then to 0ft, and eventually became negative (-1ft) even before it started moving to track me. As can be seen in the video, the drone slowly looses altitude once it moves, eventually hitting the fence/sign. There was obviously an issue with the sensors.

I'll wait to hear from DJI to see if this was a hardware issue or a software one that will need to be resolved with a firmware upgrade.
2016-12-22
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Tharg (from the
First Officer
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United Kingdom
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Aside from the stupidity of attempting this - did it ever occur to you that it just might not be a great idea to fly so close to a satellite uplink array?

Although; judging by your insistence this was DJI's fault it probably didn't even enter your head!
2016-12-22
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lildevilx
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Flight distance : 264101 ft
Canada
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just throwing this out there... while we're on the same topic. Even if his flying beside an satellite uplink, and it screws with the GPS. Shouldn't the DVS be able to tell that the mavic is dropping in elevation?
So i guess the better questoin for DJI is, would the mavic use both DVS and GPS at the same time or only the one?
2016-12-22
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EZTropical
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why didn't you have DJI CARE ??  Come On  !!   suck it up, you made a bad decision.  Move on  (without the Mavic)
2016-12-22
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GTDrone
Second Officer
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Guatemala
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Unfortunately obstacle avoidance  is not 100% acurrate it can hit things that are
in the sides up and down , and it dont detect small objects , clearly we see in the video that the quad didnt detect that but i think is normal
we know that , that system only works with big objects that are in front the quad   and when you are landing ,



2016-12-22
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Mike Mas
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Yeah this whole automation thing is a laugh!

There is so much so-called "safety" hype about flying solo with Goggles, yet its OK to use active track like an idiot and set your transmitter on the ground while the Mavic is flying around as if it has a mind of its own!

As CamStevens said; DJI is also responsible because their ads make it seem as if you don't have even consider safety!

Just love their DJI Promo Video (with their fake news animation) with two kids on skate boards, who pull these Mavics out of their back pack and fly maneuvers that even I would not dare around cliffs and caverns and through dense tree lines at speeds of 50+ mph completely out of line of site like it was nothing at all. No wonder guys are banging these things into everything in site, they are all under a false impression they are un-crashable, all the while DJI is going to the bank at $400-600 a pop for repair!    Ain't life Great?

Fly Safe - Mike
2017-7-11
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