2 Fly Aways - Log Help

[Elvis]

Today was the second time this happened. Hoping someone could look at my logs and tell me if there is something wrong with my Mavic.

First episode: I sat the Mavic on top of my car sun roof and took off after GPS lock. As soon as the mavic was airborne, it immediately started to drift quicker and quicker in a large circle away from me. After a few seconds, it was heading towards the lake in front of me and i pulled down to land. The Mavic's attitude was not level at all, and very pitched forward. Luckily, it landed in the rocks before Lake Michigan damaging all props. After analyzing the flight afterwards, I figured the GPS signal maybe was bouncing into and out of my glass sunroof and maybe the Mavic was getting a weird GPS signal to start (shadowing). Or I thought maybe the drone switched into ATTI mode and the wind took it away. I replaced all 4 props, and did not have a problem again until today.

Second episode: I sat the mavic on the ground by my office like I do most flights. Waited for a GPS lock and took off. This was my 2nd flight of the day, with no problems with my first flight. As before, as soon as the mavic took off it started to immediately drift faster and faster away from me. I looked down this time and I still saw the Green GPS flight mode, so GPS could not have been the issue. I immediately tried to control and land the mavic. Luckily there were no rocks this time, and I just damaged the front two props. The mavic once again took on a very odd attitude leaning forward and started to drift in a circular fashion away from me quicker and quicker.

I turned off the mavic and turned it on and had no problems on a short test flight after this.

I am going to the Bahamas in 2 weeks and I am afraid it is going to do the same thing and I am going to lose it in the ocean...

My gut is telling me now that maybe there is an intermittent problem with an internal sensor or gyro?

I have been flying drones for some time and have my pilot's license and am very confident this is not user error.

I have copied over to my desktop FlightRecords folder. Is it possible someone could take a look at this and maybe see if they could tell me what the problem was?

Any help appreciated.

 

[Flawless]

Calibrate the compass and IMU properly (away from metal).


Launching a drone near metal (like your car) can have a lasting effect on the drone's sensors - calibration should resolve any issues that aren't permanent.

 

[Elvis]

I re-calibrated after the first incident and never launched near the car again. The incident today happened in a field, and after a successful first flight. And have had numerous flights where something like this does not happen...

 

[BlakPhoenix]

Do you check your sensors before every flight?

 

[halley]

Do you use HealthyDrones? They have a wind report, anytime you go 5 seconds with hands off the sticks or 5 seconds driving straight forward, they calculate the windspeed. If you have uncommanded drift I would think this would be helpful data.

 

[AnzacJack]

The circular motion makes me think it is compass problem as this is a well known issue with poor compass calibration

 

[NickB]

1st incident - compass confusion.

2nd incident could be you had upset the IMU from the first incident.

 

[Elvis]

I had 30 flights between the first and second incident.. And I had a flight right before and right after the second incident that was fine.. It did not prompt me to recalibrate anything today before the flyaway/strange behavior. Sometimes before i fly, i get the message to recalibrate compass, and I recalibrate when it asks me to do so... I'm not sure if this is the case here..

 

[Elvis]

How do I analyze the DAT file from the drone?

 

[Strafe1]

You didn't say but I hope you did......replace your damaged props before subsequent flights?

 

[mmee]

I would recalibrate the IMU and then do a proper compass calibration away from any metal that could be causing interference. Make sure you are never launching near any metal such as cars fences or even rebar in concrete. Also I wouldn't call these fly aways as your drone didn't fly away but seemingly responded as it thought it should due to user error it seems. Glad your drone is still in one piece.

 

[Oingo Boingo]

1st incident - compass confusion.

2nd incident could be you had upset the IMU from the first incident.

I do agree on that one. After a crash its always a good idea to reset the IMU and recalibrate it. Also do a solid recalibration of the compass

 

[Elvis]

Props were changed, imu was recalibrated, compass has been recalibrated, yet this continues at a random interval. Was fine for 30 flights, then take off and drift/fly away.. Maybe someone could look at the dat file for me? I don't know how to do it..

 

[mmee]

Props were changed, imu was recalibrated, compass has been recalibrated, yet this continues at a random interval. Was fine for 30 flights, then take off and drift/fly away.. Maybe someone could look at the dat file for me? I don't know how to do it..

Did you post the file here somewhere. To do it you just upload it to healthy drones (now airdata.com) and the share the link to the flight here. Maybe plug in your Mavic to your computer and use the DJI Assistant app to refresh the firmware and then do IMU cal and compass cal. Cant think of anything else.

 

[Cutaway]

Props were changed, imu was recalibrated, compass has been recalibrated, yet this continues at a random interval. Was fine for 30 flights, then take off and drift/fly away.. Maybe someone could look at the dat file for me? I don't know how to do it..

Don't dismiss the good ol' defective. I'd begin a case with DJI. All these suggestions and opinions may not solve your issue. Especially the fact that most either missed or dismissed that you're a pilot. Bummed to hear about your trouble. Good luck.

 

[mmee]

Don't dismiss the good ol' defective. I'd begin a case with DJI. All these suggestions and opinions may not solve your issue. Especially the fact that most either missed or dismissed that you're a pilot. Bummed to hear about your trouble. Good luck.

Not dismissing defective. My mavic is defective too in fact it is at DJI right now waiting to get repaired (though for different reasons) I would just hate for somebody else to have to go through the waiting game like I am having to go through. Also I am not dismissing that he is a pilot. I fly corporate jets for a living myself and some of the pilots that I fly with wouldn't begin to have an idea of how to fly or operate a mavic or any drone for that matter. Don't assume that we pilots are geniuses because that is far from true.

 

[Elvis]

Here is the flight in question. It was a very short flight as I tried everything as quickly as possible to land it as it was flying away from me.

It does not look like there is a lot of data here to work with.

Here is the link - Airdata UAV - flight data analysis for drones

I tried to upload a DAT file but it does not look like this website supports analyzing DAT files?

 

[JLane]

Here is the flight in question. It was a very short flight as I tried everything as quickly as possible to land it as it was flying away from me.

It does not look like there is a lot of data here to work with.

Here is the link - Airdata UAV - flight data analysis for drones

I tried to upload a DAT file but it does not look like this website supports analyzing DAT files?

No, that site doesn't take .dat files. I'm not sure if any do, but best to just put your .dat file(s) into Dropbox or something like that. There are several users here who are quite willing and able to take a look and analyze them for you.

 

[JLane]

You can also make a screen recording of your flight's playback in the GO App. Make sure to tap the button to show the stick input overlays, too.

 

[Elvis]

No, that site doesn't take .dat files. I'm not sure if any do, but best to just put your .dat file(s) into Dropbox or something like that. There are several users here who are quite willing and able to take a look and analyze them for you.

I will do this if someone here can look at it? Is the DAT file inside the MCDatFlightRecords folder on my Ipad? I see DAT files located there. 2017-03-21_13-18-28_FLY168.DAT Or are the DAT files located directly on the Mavic itself?