Compass Error

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Hi All,

Does anyone have advice while working with support? I have a support ticket open after a fly away. On Friday I powered mine on, got ready for take off, everything was fine, 10 sats and everything else was fine. I took off and as soon as I got to 25m, it gave a compass error, went into ATTI mode and I could not control it. I pressed the return home function but it did not respond and just took off. I went to the last location indicated on the map but it was not there....long story short it ended up taking a due east course and flying for about a mile before it crashed into the High School Football Stadium @ 27 feet.
If it could not find home, it seems like it should have at least dropped down and landed when it lost signal? Maybe I am expecting too much. Here is a pic of the path, the x indicates where it was recovered.

THanks!

drone.jpg
 
Hi All,

Does anyone have advice while working with support? I have a support ticket open after a fly away. On Friday I powered mine on, got ready for take off, everything was fine, 10 sats and everything else was fine. I took off and as soon as I got to 25m, it gave a compass error, went into ATTI mode and I could not control it. I pressed the return home function but it did not respond and just took off. I went to the last location indicated on the map but it was not there....long story short it ended up taking a due east course and flying for about a mile before it crashed into the High School Football Stadium @ 27 feet.
If it could not find home, it seems like it should have at least dropped down and landed when it lost signal? Maybe I am expecting too much. Here is a pic of the path, the x indicates where it was recovered.
If you are trying to deal with DJI you need to have a good idea of what happened.
The first thing to do is to go to https://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.

Come back and post a link to the report it provides and someone here might be able to analyse it and give you an understanding of the cause of the incident.

Also as it's relevant, when/where did you last calibrate the compass before the flight?
What was the launch point like?
 
Welcome to the Forum!,

Your log is good, your flight scary.
RTH as I understand it fails, with the compass.
You must have had a wind not in your favor either. :rolleyes:

So somebody else is going to have to help on this log.

I believe with experience in Atti mode, you could have got control of it.

Is this someplace you always do compass dance?

No warning until you were in the air. :eek:

Rod
 
Thanks,
I have only had 15 flights on it and it seems I always have to calibrate the compass (last time was before the previous flight). This was the first time I had gotten any compass errors in the air. For a year prior to this, I had been flying a drone without GPS / always manual control.
FWIW, The wind would have been a headwind relative to the direction it was flying (from the west).
 
Max speed 36 mph, RTH 22 mph I think?

Scary Flight :eek:

How much damage?

Rod
 
@RodPad - A lot. Note that the last known location along the flight path and flight log is not where it was found. I thought it was gone forever but the local police department found it at the stadium a about a mile a way.
 
So what was your RTH set for? The elevation changes up and down during the Go-Home mode.

I guess it would be pretty damaged if it an building at 38 mph.

Rod
 
RTH set to 30m but it did not matter because it did not work. The copter took a due east heading towards the football stadium and never attempted to RTH.

The orig pic in the first post shows the known path the and the last known location before it completely
Lost contact. From there it flu east until it hit the stadium, where the red x is.
 
Paging, @Meta4 or anybody, got anything to add, subtract, or equal ?

Rod
 
Is go App Android 3.1.2? That version has a mobile GPS location problem set 2 miles away which could somehow end up being your home position.
Compass problem isn't part of the known 3.1.2 issue though.
Have you tried IMU calibration?

Sent from my HTC 10 using PhantomPilots mobile app
 
@DanMan32 thanks, I'm using iPhone. I did an IMU Calibration the previous day, was very cautious about making sure it was cold before calibrating.
 
Last edited:
Is go App Android 3.1.2? That version has a mobile GPS location problem set 2 miles away which could somehow end up being your home position.
Compass problem isn't part of the known 3.1.2 issue though.
Have you tried IMU calibration?
If you look at the log, it only has one home point.
Do you think IMU is going to fix it. :D

Rod
 
@Bzilla - Sorry about your loss. Thanks for sharing your story.

Ever since I began flying I've had this habit of lifting off from the ground and hovering at 6 or 10 feet (or perhaps a bit higher, depending on my surroundings) off the ground. Then I'd triple check everything. I'd make sure I had a good satelite lock, check that the altitude and distance numbers on the screen make sense, check the controls, make sure that I removed the gimbal lock, etc. Just wanting to make sure everything is as it should be.

After reviewing some of my videos, I noticed that this abundance of caution usually wasted about two minutes. That's two minutes of battery charge that could be put toward a slightly longer Litchi mission. I've been getting kinda ballsy with these one-way Litchi missions lately. Pushing the limits. Hovering for minutes makes for pretty boring video too.

A couple of days ago, I decided to eliminate these battery-sucking hovers, opting instead to simply launch the mission straight from the ground on my next flight.

Hmmm. Perhaps not.

Looking at your log, it seems that you wouldn't have been alerted to a problem until after the bird left the ground. The fact that you continued to ascend for another 8 seconds to an altitude of 80 feet shows that you weren't aware of a problem until it was possibly too late to simply bring it back down safely.

Hovering above the takeoff point and checking everything as I have been doing (and now, will continue to do) would catch a problem like this.

For that, I thank you.
 
Yes,
I can't see that he was at fault, I still wonder if was possible to fly it as Atti, that I still don't understand.

Rod
 
I still wonder if was possible to fly it as Atti, that I still don't understand.

It probably would have been flyable in ATTI mode.

Of course, it would be easy to sit back and bloviate on what we would have done in this situation.

I have quite a bit of experience flying and I can't say with certainty that I would have handled the situation any differently given the conditions.

Here's how things may have gone down from looking at the data available:

OP took off from his driveway. DJI GO app would have alerted him of an issue immediately but the OP was probably looking at the quad rather than the screen. Logical. When the quad gained altitude it flew over the house and probably out of the OP's line of sight. This is how it appears on the map. This was probably the point when the OP realized something was seriously amiss.

Of course, one might assume that the OP immediately looked down at the screen for an answer but, that screen might have been very difficult to see if it was a daytime flight. Perhaps too difficult to try to navigate home using FPV as well.

OP then did the logical thing in this now panic situation. Hit RTH...which accomplished nothing useful because of the compass error.
 
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You must have been looking over his shoulder. :D

So, I have been testing Litchi in the way-point mode only, and it reads out (speaks out) every (you set) secs. I like that, hope it does the same in normal flight. Default I think was 10 secs.

Rod
 
For the most part. I was looking at the screen initially, and the alert did not pop up until it was at hovering altitude. I did hit the RTH and when it appeared to not do anything I hit cancel but it asked "IF I WAS SURE". That made me doubt canceling and to trust it. Soon after that it was out of site.

One thing that does not seem right is if RTH does not work with a compass error you should not be able to enter that mode. Much less ask if you are sure you want
 
Yes, good thoughts.

Rod
 

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