Toilet Bowling and Flying Over Water

[mattdt83]

Hey folks,

So a while back I flew my Phantom 4 over a marine lake where I live. During the flight the quad started circling uncontrollably in large circles and I fought to keep it up in the air and I did eventually regain control after a few minutes or gut wrenching terror.
When I did my CAA training I questioned it and was told it was toilet bowling and could be GPS reflection from the large body of water? Kind of fits and the way out would of been to flick over to ATTI and fly it out of danger.
Since having my Mavic I've been a bit nervous about the same thing happening and not having ATTI to flick to in the event of this. Has anyone else ever experienced this type of thing over water? Or toilet bowling in general?

Thanks gang, new here, couldn't find much on the topic, but apologies if it's been discussed.

M

 

[_milo_]

I saw my friends Mavic go into a toilet bowl when he was returning to home, it wan't over water, over land, low in altitude, he had a hard time controlling it, the toilet bowling got progressivly worse. He got it down, but nicked a prop against my truck bumper.

The Mavic is supposed to go into atti automatically with compass issues, but his didn't, it would be nice to have the option to put it into atti. If you experience a toilet bowl on the Mavic, and its staying in GPS, you can try yaw'ing it 360 degrees, that can sometimes clear the problem.

I haven't had any issues, its good practice to check your compass values before you launch to make sure there isn't anything interfering nearby.

 

[BudWalker]

.... its good practice to check your compass values before you launch to make sure there isn't anything interfering nearby.

Another check the pilot can do is look and see if the red triangle is pointing in the direction it should be. Very often the compass values will look OK when there is a significant compass error that will cause problems after launch. In these situations the red triangle will pointing the wrong way.

 

[stratos]

If this starts happening switch to sports mode and then back into gps mode

 

[Bilzy6164]

Hey everyone gotta question so I'm going away fishing on a boat for two weeks gonna update form ware and everything on Wednesday then I leave Thursday, before we launch the boat should I go somewhere like an oval and calibrate compass sensors etc because likely I won't be able to do it in the boat am I right? And how often do u calibrate, I have never calibrated it but I haven't had it or flown it very long, also flying over water do I definetly turn off OA and VPS

 

[Robbyg]

The few cases of TBE that I have seen have been over land. The craft in most cases switched to Atti mode. In some cases the pilots still crashed because they did not realize it was in Atti mode.

As for compass calibration I have only done it about 3 times in the last 4 months. I only did them because I was in nice open areas. You really do not need to calibrate it unless you get a compass error when you are in an area that is free of metal or man made magnetic fields. Once you have done a good calibration out in the open I suggest you do not mess with it again unless you have a crash or do a firmware update.

 

[Bilzy6164]

Ok awesome no worries will do thanks for the reply!!!

 

[JLane]

If this starts happening switch to sports mode and then back into gps mode

I haven't heard of this before as a fix for a TBE event. What's the rationale behind it? Have there been cases where this has worked?

 

[GerdS]

If this starts happening switch to sports mode and then back into gps mode

Haven't heared of this, but have heared that in case of an TBE you should yaw the Mavic for one or more 360° turns for a temporary re-calibration of the compass.

 

[stratos]

Haven't heared of this, but have heared that in case of an TBE you should yaw the Mavic for one or more 360° turns for a temporary re-calibration of the compass.

You can also "pause" the craft and this will sometimes give you back the control.
It happen to me only once.

 

[Partylikeits1995]

The few cases of TBE that I have seen have been over land. The craft in most cases switched to Atti mode. In some cases the pilots still crashed because they did not realize it was in Atti mode.

As for compass calibration I have only done it about 3 times in the last 4 months. I only did them because I was in nice open areas. You really do not need to calibrate it unless you get a compass error when you are in an area that is free of metal or man made magnetic fields. Once you have done a good calibration out in the open I suggest you do not mess with it again unless you have a crash or do a firmware update.

My understanding is you should also recalibrate when you fly in new locations. E.g. Another town/state. I travel to a new town every 7 days so I get an error to recalibrate regularly.

 

[seadog]

For the few seconds it takes would be nuts not to re-calibrate when you fly from a different area. Myself I do it all the time.

 

[BossBob]

My understanding is you should also recalibrate when you fly in new locations. E.g. Another town/state. I travel to a new town every 7 days so I get an error to recalibrate regularly.

My understanding was that you should only recalibrate the compass when the drone requests it.

 

[GerdS]

My understanding was that you should only recalibrate the compass when the drone requests it.

Or if you have changed to a location more away than maybe 100 miles from last calibration, e.g. such as after delivery of your Mavic.

 

[BossBob]

Or if you have changed to a location more away than maybe 100 miles from last calibration, e.g. such as after delivery of your Mavic.

No. Page 52 of version 1.6 of the Mavic Pro User Manual, "Only calibrate the compass when the DJI GO 4 app or the status indicator prompt you to do so."

 

[mark_t]

My understanding is you should also recalibrate when you fly in new locations. E.g. Another town/state. I travel to a new town every 7 days so I get an error to recalibrate regularly.

If you are getting a calibration error that often then something is wrong.

The Mavic does not require frequent recalibration even if you are changing location frequently, and the more often you do this the greater your chance of getting a bad calibration.

People often see the option to recalibrate the compass in the start up screen right after you hit 'Go Fly' and mistake that for an error telling them to recalibrate, it isn't.

 

[stratos]

If you are getting a calibration error that often then something is wrong.

The Mavic does not require frequent recalibration even if you are changing location frequently, and the more often you do this the greater your chance of getting a bad calibration.

People often see the option to recalibrate the compass in the start up screen right after you hit 'Go Fly' and mistake that for an error telling them to recalibrate, it isn't.

Thats is right. Also if you start up / turn on your craft on top of something that could contain metal the compass can go haywire.
This weekend I was ina part and wanted to take off from a wooden table and got the compass error. I thought it was an app bug or something but then I realized that of course in order to build the table you have to use this big metal nails, so, they were causing a bit of bad readings.

So I powered of and instead took off from the grass, no issues with the compass didnt needed to calibrate.

Now, regarding manual calibration I would suggest for you to do it if you are going to fly in a place in which you have never flown and its away from a previous location.
This would allow to calibrate your compass properly for the location.