Yesterday in a series of test flights, my airplane with a 2.5 APM struggled to find way points and at some times even the direction to go.  In effort to diagnose the problems I notices there was no mag data on the graph.  Am I looking this correctly?

Attached is a graph of throttle and mag data.  

What suggestions do you all have for me to correct this?

Thank you.

Bret C

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THIS may be a factor in some of the information of a playback of your log.

That is from the Arducopter section but it may apply to Arduplane as well.

Let us hope one of the active plane folk jump in.



In the above pic, it looks like the aircraft was heading for an impact.

The compass display did change as the flight progressed.

Nice flying site!


Hello Doug:

Thank you for taking time to look at the logs and give me some feedback.  OK - the fact that the mag data is for multicopters may explain the fact that there was no data.  I am still learning all of this.

What do you think is causing faulty information in the "distance to MAV" section?

Also, I should have included in the original post that I am using Ardrupilot 2.69 when I recorded the above flights.  However today I just downloaded and installed APM version V.2.7.  If my fingers can bear the cold, I will further test today.

Thank you for your help!

Bret C


I did not mean to imply that the mag data is not used in ArduPlane; just that the referred information is from the ArduCopter section. HERE is the ArduPlane section instead. Different folk work on different sections so there will be variations.

When played back, it clearly shows the compass information changing with the attitude of the aircraft. Way Points are based on LAT and LONG from GPS as discussed HERE.

The 'MAV' error may be due to discussion found HERE.

Again, from the copter section. Watch the video. Randy discusses the reasons for the big numbers. Probably your 'home' settings are not correct in MP.

The red line and others are indications of APM/aircraft heading and direction to WP, etc. This is fairly easy to confirm at home by connecting via USB to the aircraft with MP running and noting the Flight Data screen. If you know where North is in relation to how the aircraft if sitting, a line will be pointing that way - assuming the mag is calibrated and not skewed from massive amounts of ferrous material nearby.



Great information and help.  I suspect that all the answers to my challenges are in the DIYdrones web site, but sometimes I struggle with finding it.

Also - yes, we are blessed to be able to use our local airport for flying.  There is not much full scale activity there so the city allows us to use it.  It is a great place for testing.

Thanks again for your help and support!

Bret C 


No further help is needed on this thread.  I learned today the real problem is the fact that when the mode is switched to AUTO, the APM actually goes to RTL even though the HUD display on the Flight Data of the mission planner says otherwise.  Go to this thread for information about itl

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