Atti Mode unintentionally

[rlphoto69]

Have a question. All was well first couple seconds of take after compass calibration etc and all of a sudden controller reads compass error and aircraft goes into Atti mode just after takeoff and becomes somewhat uncontrollable. Thank god I was able to land. Question is, has anyone else experienced this. Switch was in P mode but couldn't get GPS after that. Apartment complex that I was never in before and also in a different state. Did IMU calibration as well. Not sure if there was a lot of interference/wires in area. Any input would be appreciated.

 

[msinger]

This often happens after calibrating the compass near magnetic metal objects and/or taking off from a surface that contains magnetic metal objects (e.g. a sidewalk).

 

[rlphoto69]

Thank y

This often happens after calibrating the compass near magnetic metal objects and/or taking off from a surface that contains magnetic metal objects (e.g. a sidewalk).

Thankyou. Never seen this before and got a little worried.

 

[msinger]

Did you do either of those things?

 

[rlphoto69]

I did calibrations afterwards on both the IMU and the compass and still could not get it to recognize GPS I am going to try it later today in a different area and hopefully that will let me know if there was a problem or not

 

[Numone]

Oh yes.... I did exactly that - compass cal over what must have been rebar and got exactly that result - into ATTI and waaaahoooaa there! LOL now but no so much at the time. Since that I often practice flying and landing in ATTI, just to be calm and collected and have the experience if it happens again.

I have never done an IMU cal outside. I've only done two. The first when I got the 3A and the second using the fridge trick a few months later, both indoors and on a perfectly flat surface.

 

[rlphoto69]

I'm hoping my compass is not bad. I came back inside to do the IMU calibration. But then just decided to try today in a different area to see if indeed it was some type of strong interference. I really appreciate everybody's help this site has been great

 

[msinger]

Did you check out the flight log from the flight in your first post above? If not, you can upload and view it online here. Perhaps it'll explain what happened.

 

[Meta4]

I'm hoping my compass is not bad. I came back inside to do the IMU calibration. But then just decided to try today in a different area to see if indeed it was some type of strong interference. I really appreciate everybody's help this site has been great

The compass is going to be just fine, but you may have given it a bad calibration.
Go to a magnetically clean area and give it a good calibration and stick to that and avoid launching from reinforced concrete.

 

[Numone]

I'm hoping my compass is not bad. I came back inside to do the IMU calibration. But then just decided to try today in a different area to see if indeed it was some type of strong interference. I really appreciate everybody's help this site has been great

So you didn't recalibrate the IMU or the compass? Personally, I would've especially as you said you did the IMU outdoors. Belt 'n' braces to do them correctly IMO. Still, it's your AC, so your call.

 

[rlphoto69]

So you didn't recalibrate the IMU or the compass? Personally, I would've especially as you said you did the IMU outdoors. Belt 'n' braces to do them correctly IMO. Still, it's your AC, so your call.

I did a compass and IMU calibration before I flew initially after bringing the AC to a different state as well as a long car ride. A conversation I had with DJI once to calibrate each one before every flight? After the failure I recalibrated again, but as Meta4 said, Ill wait till I can find a interference free area and try it all over. Thanks everyone

 

[Numone]

I did a compass and IMU calibration before I flew initially after bringing the AC to a different state as well as a long car ride. A conversation I had with DJI once to calibrate each one before every flight? After the failure I recalibrated again, but as Meta4 said, Ill wait till I can find a interference free area and try it all over. Thanks everyone

Sorry I misunderstood you.
Great, thats deffo the best idea and at home, I hope?
The DJI comment is nonsense. I haven't calibrated the IMU for at least seven months and the compass only once since then. During this time I've travelled '000s miles and > 1,300 miles from home on one trip. Not had a single issue with the AC.

 

[Meta4]

A conversation I had with DJI once to calibrate each one before every flight? After the failure I recalibrated again, but as Meta4 said, Ill wait till I can find a interference free area and try it all over.

DJI people are not always reliable for tech information.
They set you (and many others) wrong with calibrate before every flight info.
It was always unnecessary and introduced the risk of a bad calibration.
Here's what being in the calibrate-every-flight club can do:

For the P4 pro, DJI have finally changed the badly worded compass section of the manual.
What they say now is very different from what they used to say.
Look at the top of p57 to see what they recommend nowdays.

 

[rlphoto69]

Very helpful information. Doesn't give me a warm and fuzzy about DJI tech support. Maybe they better update their tech reps too. Just my opinion, but when you pay up to $2000.00 for a piece of equipment, one would expect to get some decent tech service when there is a problem. Thanks again Meta4. Sure appreciate it.

 

[Mo of Pocatello]

Today My p4p also went into atti mode by itself. It was forced into IMU calibration just before the flight. Don't know why. Was just flying from our own driveway!


Sent from my iPhone using PhantomPilots

 

[trevsdad]

This often happens after calibrating the compass near magnetic metal objects and/or taking off from a surface that contains magnetic metal objects (e.g. a sidewalk).

This same event (..sudden slip into ATTI mode while still in 'P') happened to me this past weekend during a job.

Sensors all read normal before takeoff and 3-previous flights that day all proceeded normally. I was dealing with a 10kt wind gusting to 20kts but I kept the Phantom low (about 200 AGL) so it was do 'able.

My question is this...all flights, except the event described, took off from grass...the 'slipped in ATTI mode' flight originated in a parking lot on an asphalt surface. I've taken off from similar surfaces before with no problem, but do you think this ATTI issue is a result of the asphalt surface as suggested by msinger (...not aware that re bar is part of the construction of this surface) or could it be somehow related to the relatively high winds that day?