fans6d1b505c Posted at 2017-6-7 23:54
Ok finally this conversation is discussion is leading somewhere

I came here to find the exact reason for the crash of my drone and to find out if it is a mavic specific problem. As it seems, the Metal is a problem to the Mavic as you state. So you have to be especially cautios with the mavic in comparison to other drones.

First you said you came here to find out exactly what happened to your Mavic, you were asked for flight log and dat file, for some reason you decided to hold back that dat file you had, and expected people here to find out exactly what happened with the flight log on its own.

I don't think people here and certainly not Droneflying was trying to catch you out in some way, but rather he was trying to help you find out what happened and how to avoid this in the future, and I was of the same mindframe.

You say this is particularly a problem with Mavic not true , I have left a link below of a very recent case for P4Pro and it's the same in most Drones of this size and price range.

Page 50 in your manual does explain about flight environment magnetic interference etc..

It also should be in everyone's checklist to check compass.

https://forum.dji.com/forum.php? ... &fromuid=260008

Ok, tell me how to upload that dat file because the link provided only sais .txt files

I AM airtrafficcontroller on the control tower at the airport of Bremen, germany

Geez people... i know a LOT about civil aviation, not all, but a lot

Vuperman Posted at 2017-6-8 02:46
Ok, tell me how to upload that dat file because the link provided only sais .txt files

I AM airtrafficcontroller on the control tower at the airport of Bremen, germany

I'm sure with your experience you have plenty to offer others myself included around here, and you are more than welcome here.
This link may help with dat file.

https://datfile.net/DatCon/fieldsV3MP.html

Vuperman Posted at 2017-6-8 02:46
Ok, tell me how to upload that dat file because the link provided only sais .txt files

I AM airtrafficcontroller on the control tower at the airport of Bremen, germany

You'll have to upload the file to DropBox and then provide a link to it in this thread. I'm surprised that you'd know how to get a DAT file off your Mavic and that it might be worthwhile to do so without also knowing how to post a link to one -- but I suppose anything is possible.

hallmark007 Posted at 2017-6-8 02:49
I'm sure with your experience you have plenty to offer others myself included around here, and you are more than welcome here.
This link may help with dat file.

He claims to have already downloaded the DAT file and just needs to know how to post a link to it on the forum.

DroneFlying Posted at 2017-6-8 02:55
He claims to have already downloaded the DAT file and just needs to know how to post a link to it on the forum.

Ok sorry,

Look what you do when you use words like "claim"...
Anyways, of course i have uploaded files to the internet before, i just thought the was a special way to upload the .dat file so it is easily readable like the .txt file, because if you just open it with an editor it's just encripted text

https://wetransfer.com/downloads/23dc51abe9deaa92df9d6655884d774a20170608152120/cddc20cea104c716694293b6b55d75cb20170608152120/ac7d9a

Here we go

Vuperman Posted at 2017-6-8 07:50
Look what you do when you use words like "claim"...
Anyways, of course i have uploaded files to the internet before, i just thought the was a special way to upload the .dat file so it is easily readable like the .txt file, because if you just open it with an editor it's just encripted text

That's not a DAT file from your Mavic . . . or anyone else's. Did you perhaps get that from your remote? The instructions for correctly downloading a DAT file are here, but of course if you "HAVE saved the DAT file befor [you] sent the Drone in" then you already knew that, right?

Well it's the dat file that was in an underfolder of the directory on my iphone in which i found all the log files and the date and time in the name of that file is exactly the same as the flight
And in that folder i can find a dat file for every other flight that i did with the drone

Btw In aviation we use magnetic compasses and gyros. Aircraft are not affected by metal structures, this would be most hazardous. Airplanes themselves are big metal objects!
And the compass in drones are most likely solid state compasses. There might be some solid state compass devices sold for aviation too, but i am sure that it would be shielded from any possible interference and would only be used on small airplanes

Vuperman Posted at 2017-6-8 08:30
Well it's the dat file that was in an underfolder of the directory on my iphone in which i found all the log files and the date and time in the name of that file is exactly the same as the flight
And in that folder i can find a dat file for every other flight that i did with the drone

In other words, you don't have the DAT file from the Mavic? Yeah, that's what I thought.

Oh okay
Sorry i was mistaking the File 2017-05-19_19-42-43_FLY051.DAT found in the dji go Folder in my iphone for the .dat file of the Flight which i did on 19.05.2017 at 19:42

I still think it's the correct file, i just need to find a way to make it readable

Vuperman Posted at 2017-6-8 08:30
Well it's the dat file that was in an underfolder of the directory on my iphone in which i found all the log files and the date and time in the name of that file is exactly the same as the flight
And in that folder i can find a dat file for every other flight that i did with the drone

If you really need to know what happened, then you could always ask dji they must already have access to your dat file, they should have your information, but can sometimes be difficult to information out of them.

If your looking for drones with extra shielding for compass MATRICE 200 is equipped to fly close to steel structures pylons telecom towers etc. It will set you back 5k plus and is due to be released soon.

Red Defiant Posted at 2017-6-7 16:45
I can appreciate your insight but I assure this was not an operator error. I have taken off from my patio numerous times. At the time I took off I was connected to 3 sats, I flew to the center of the yard and waited for it to finish syncing up with the rest of the GPS/GLONASS sats which it did, connected to around 15, then waited for the "Home Point has been updated...." notification, which I got. I continued to hover there for a few seconds, not even touching the sticks. Checked the aircraft status, and everything was green. Then without me moving the control sticks the drone flew back and to the left at a 45 degree angle (no altitude change). When I noticed this was happening I moved the controller sticks to try to make it fly forward and to the right. The Mavic did not respond, and continued to fly back and to the left until it hit the wall. I even hit the pause button before it hit the wall and this did nothing. I had no compass error or IMU error. I had full GPS signal, full controller and video feed signal and over 90% drone battery and over 90% controller battery. I have flown this exact pattern many times before and since without incident. I have flown in far more restrictive places both indoors and outdoors with no incident. Not operating it like a kid with new skates.

Thank you for the correction.  I wouldn't have made all of the statements I did if you had supplied more complete information in your original post.  Given the info you have now provided I would have a talk with DJI about the issue.

So far, my early (Nov 2016) build Mavic has shown no sign of any problems at all, but I admit to having a low number of hours on it.  I've flown the P3A for almost 2 yrs without an unexplained, non-pilot error, and only one minor pilot induced problem.  That doesn't make me cocky about flying though.  Like the other guy posted, all has worked just fine, but the posts on this forum scare the heck out of me.  I need to get out and fly it some more, obviously.

I also agree though that many more people who get on here and rant about crashing their bird and DJI should replace it, haven't even taken the time to thoroughly read the manual (a current version).  Some don't read it at all.  It takes several passes in the manual to catch some of the smaller things that are important to safe flight.

Best of luck in your flying.

Gary

Vuperman Posted at 2017-6-8 08:54
Oh okay
Sorry i was mistaking the File 2017-05-19_19-42-43_FLY051.DAT found in the dji go Folder in my iphone for the .dat file of the Flight which i did on 19.05.2017 at 19:42

The .DAT file for this flight is on the Mavic itself, not the tablet or Controller.

I looked at this flight some. Specifically, I looked at the .txt that can be downloded from your Phantom Help link. Without the .DAT it's hard to tell, it's hard to tell if the AC was launched from a geomagnetically distorted site. Sometimes you can look at rudder, aileron and the direction of flight to see if that is inconsistent with what Yaw is showing. The log shows Yaw to be -98. Right aileron was applied at 12 secs but the AC moved in a westerly direction; the same direction as indicated by Yaw. This would imply the AC was actually facing south (not west) and was moving laterally. The same indication comes at 21 secs where Right aileron and back elevator were applied. The AC behaves like it's facing south but the Yaw value is west.

Was it facing south at launch?

Yeah budwalker, it was facing south!

This incident may also have been caused by a broken prop. This is what I first thought. At about 23 secs pitch and roll both go negative which is then followed by CCW spinning. The CCW spinning is indicative of a propulsion issue in either leftBack or rightFront. The pitch and roll values would occur if the leftBack had lost propulsion.

Vuperman Posted at 2017-6-8 12:55
Yeah budwalker, it was facing south!

Then, most likely the launch site was geomagnetically distorted. Looks like it was a pier? Maybe some steel understructure?

BudWalker Posted at 2017-6-8 13:03
Then, most likely the launch site was geomagnetically distorted. Looks like it was a pier? Maybe some steel understructure?

Maybe some steel understructure?

That appears likely.

Yeah, with concrete on top and this is what droneflying was pointing as a reason for the drift and uncontrolable behaviour as well.

I didn't have any warning in the beginning

And yes, at 0:23 the propeller is broken, because the drone hit the house in that moment

Vuperman Posted at 2017-6-8 19:31
Yeah, with concrete on top and this is what droneflying was pointing as a reason for the drift and uncontrolable behaviour as well.

I didn't have any warning in the beginning

Unfortunately, the only "warning" you can get in this situation is that the heading indicator in the Go App display (i.e., the red triangle) is not the same as the actual AC heading.

EDIT: It's been pointed out to me that it's possible the Go App could have issued a "magnetic interfence" warning prior to flight. But, it's also possible that it didn't. It depends on the particulars of the distortion and the placement of the Mavic in that distortion. The field diistortion has two aspects; 1) change in direction , and 2) change in strength. The Mavic can't detect a change in direction, it can only detect a change in strength. It's often the case that any field strength change is not enough to trigger the "magnetic interfence" warning.

Since you didn't mention any "magnetic interference" warning I'm assuming none was issued. That being the case, the only "warning" would have been the inconsistency between the Go App display and the actual heading.

BudWalker,  here's something I find a bit curious, but it may be nothing but wind.   While still in AutoTakeoff, and before any stick movement, the aircraft began to drift.  Only a couple of meters, but that seems to me a concern.

BudWalker Posted at 2017-6-9 07:05
Unfortunately, the only "warning" you can get in this situation is that the heading indicator in the Go App display (i.e., the red triangle) is not the same as the actual AC heading.

EDIT: It's been pointed out to me that it's possible the Go App could have issued a "magnetic interfence" warning prior to flight. But, it's also possible that it didn't. It depends on the particulars of the distortion and the placement of the Mavic in that distortion. The field diistortion has two aspects; 1) change in direction , and 2) change in strength. The Mavic can't detect a change in direction, it can only detect a change in strength. It's often the case that any field strength change is not enough to trigger the "magnetic interfence" warning.

That's why I was hoping to see the DAT file: so we could confirm whether or not the distortion was detected. But at least we do know that this was very likely caused by a magnetic distortion that resulted from the choice of takeoff location.

Griffith Posted at 2017-6-9 11:06
BudWalker,  here's something I find a bit curious, but it may be nothing but wind.   While still in AutoTakeoff, and before any stick movement, the aircraft began to drift.  Only a couple of meters, but that seems to me a concern.

That's kinda interesting. I don't know how position hold is done during auto takeoff. If it's done with GPS then the drifting is probably not actually drifting. Since Yaw is compromised it's expected that the AC won't be able to hold position very well. Every time it goes to correct the compromised Yaw causes it to go in the wrong direction. But, if the vision system is used to hold position then I'd expect it to do better than it did. That is, unless, as in this case, the AC is over water and the vision system can't do very well.

BudWalker Posted at 2017-6-9 16:04
That's kinda interesting. I don't know how position hold is done during auto takeoff. If it's done with GPS then the drifting is probably not actually drifting. Since Yaw is compromised it's expected that the AC won't be able to hold position very well. Every time it goes to correct the compromised Yaw causes it to go in the wrong direction. But, if the vision system is used to hold position then I'd expect it to do better than it did. That is, unless, as in this case, the AC is over water and the vision system can't do very well.

Hey Budwalker sorry for interrupting this thread, but there's a similar case at this link if you had time you might have a look at his dat file.

https://forum.dji.com/forum.php? ... &fromuid=260008

When or more importantly why is it wrong to take off with 50% battery. I've been flying for years and never had a problem. If I'm between a shot and the battery is 40-50% I'm taking off - this does not crash a drone!

Thanks

Mike

Yes i can confirm the drift was no wind and it moved away without me doing anything
It drifted slowly fist and then quicker, so i started to counteract by pulling the sticks

Bit the drone behaved uncontrollable and ran into the house in 0:23 with high speed

Boomstrike, he didn't say the half empty battery was the reason for the crash but that he thinks it is not a good idea to take of with 50%

I personally agree with you and if he were consistent, he would have to return the drone everytime he drops below 50%

But that is a personal matter

Vuperman Posted at 2017-6-11 07:07
Boomstrike, he didn't say the half empty battery was the reason for the crash but that he thinks it is not a good idea to take of with 50%

I personally agree with you and if he were consistent, he would have to return the drone everytime he drops below 50%

Again your showing your ignorance, continuing flying on a battery at 50% is a lot different than starting your flight or mission on a battery with 50%, if you read your manual it will clearly tell you that you should take off with fully charged battery and if you have a look at any preflight check list, you will see fully charged batteries will be number 1 on flight list.

checklists are something you should very familiar with working in aviation as aviation lives and dies by them .

In aviation, a preflight checklist is a list of tasks that should be performed by pilots and aircrew prior to takeoff. Its purpose is to improve flight safety by ensuring that no important tasks are forgotten. Failure to correctly conduct a preflight check using a checklist is a major contributing factor to aircraft accidents.

DJI products are very unpredictable just like anything else.  Anything could go wrong at any given time either mechanically or electrically.  It's a coin toss weather you get a good one or a bad product.

BoomStrike Posted at 2017-6-9 17:37
When or more importantly why is it wrong to take off with 50% battery. I've been flying for years and never had a problem. If I'm between a shot and the battery is 40-50% I'm taking off - this does not crash a drone!

Thanks

To answer your question, you can take off on a partially charged battery if you take care to land by the time the first battery cell reaches 3.4V. If you fly beyond that, you really need to know what you're doing because you can get into some tricky situations when trying to fly on batteries in the 3.0V - 3.3V range.

And I didn't say taking off on low battery would cause the crash, there was a post here recently a guy took of with battery 40% after two minutes it had reached critical battery and landed his aircraft, it was only on questioning him that the battery was in the drone for 7 days, so while you can give out advice that it's fine to take of with battery at 40% it's not always a good idea.

Explain to me the difference in "starting" with a 50% battery and "continuing" with a 50% bettery please

Checklists are mandatory, my whole work cosists of checklists over checklists
But for me that battery point could be altered to: batteries checked and suffice your mission target plus reserves

But you can do whatever you like of course

Vuperman Posted at 2017-6-11 09:53
Explain to me the difference in "starting" with a 50% battery and "continuing" with a 50% bettery please

Checklists are mandatory, my whole work cosists of checklists over checklists

Read my post to boomstrike. Your problem is you seem to know more than everyone here won't accept any advice, because you work at ATC but if that was true you might not have crashed your drone...

Well i guess the aircraft i am used tonwork with are just much much more reliable ;)

And your post to boomstrike didn't answer my question. If you CONTINUE flying with less than 50% battery, you can reach that point beyond 3.7 V on the first battery cell just the same... I really did not understand and woul like to have your advice!

Vuperman Posted at 2017-6-11 10:36
And your post to boomstrike didn't answer my question. If you CONTINUE flying with less than 50% battery, you can reach that point beyond 3.7 V on the first battery cell just the same... I really did not understand and woul like to have your advice!

I won't waste any more of my time on someone who knows everything already . Good luck.

Vuperman Posted at 2017-6-11 10:23
Well i guess the aircraft i am used tonwork with are just much much more reliable ;)

So long as there not relying on you...

hallmark007 Posted at 2017-6-11 10:55
So long as there not relying on you...

I'm sorry, but this is BS. I did a lot of (GA) flying in Europe and those ATC guys are the best. We as pilots basically trust them with our lives.
As a newbe to flying a mavic and this forum i am really interested in all these stories and experiences, but i have to say this all scares me off a bit.

marcelkoks Posted at 2017-6-11 14:47
I'm sorry, but this is BS. I did a lot of (GA) flying in Europe and those ATC guys are the best. We as pilots basically trust them with our lives.
As a newbe to flying a mavic and this forum i am really interested in all these stories and experiences, but i have to say this all scares me off a bit.

That doesn't give them the right to be rude when people who are trying to help, instead of trying to push my buttons he should have been thanking budwalker for all his effort to help.

I have great respect for ATC I have to work with them several times a year and I find them great.

Vuperman - listen to only about 10% of what you hearing on this forum.  Like the loser using the skateboard analogy - he hasn't a clue what he's talking about. On the other hand, I see a few of guys helping you out, you just have to filter it out, for the most part there is some good guys here!

If you flying around and the battery goes to 50% or if you start a flight and the battery is at 50% its "Exactly" the same thing and there is absolutely nothing wrong with that. What's the sense of having a battery and only use 50% of its capacity.  The helicopter (and battery) could care less, as long as the battery is above the critical level all good!

Regretfully there a lot of rude users on here hammering you when your trying to get help. I'm sure when they fired up their first drone they knew everything there was to know about drones and never had to ask or read anything.

Regards  Mike