Hi All,

Running DX8 with spektrum satellite on pixhawk, latest firmware.

Radio has been calibrated 3 times all perfect 1500 centre sticks. 

I am however getting a -2.0 offset on nav_pitch in FBWA mode. Any ideas how to fix this without adjusting the trim values on the radio as it needs the correct trims for manual flight. 

I have tried increasing the deadband zone on RC2_DZ from 30 to 60. This didnt help. I also changed the RC2_TRIM from 1500 to 1455 this does change the value close to 0 but i dont see why i should do this. As the RC calibration screen is showing 1500 as neutral very accurately and repetitively. 

Help would be greatly appreciated. Thanks

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Hi Nigel

Could you resolve the issue? I have the same doubt.

Kind Regards


This is driving me crazy! Please help me too as I can not get around it. When I switch to FBWA the plane pitches up a lot, so much it goes vertical. 

Any help is greatly appreciated.

Thank you.

The likely reason is that you didn't trim your plane before.You have to trim the control suface manually, the RC have to be in neutral position.....

Thank you Juan, 

Thank you very very much for your reply.

Just to clarify... I will use trim_auto and after the new trims are saved I should keep the physical trims position of the elevons while keeping the trims on the RC to neutral. Is this correct?

After I finish the trim_auto procedure should I center the RC trims?

I believe the following video explains it but I was not quite following. https://www.youtube.com/watch?v=ucy6VnlMHy8 ;

Thank you again, 



Apparently , auto-Trim function has to work, like you mention. but I read many comment about the manual trim gives better result than auto-trim. I never used that function, so  I can not give my personal opinion. I only have experience made all manually.

Hello again guys!

Firstly, I would like to thank Juan Pablo Gayoso for the great tip he gave me in getting my wings in the air. Pablo, today I managed to get it right following your advice.

In result the plane flies great! 

Thank you, 

George (Gastaroll)

great!.....It knowledge cost me many "&%!* in my pants" moments, and crashes. It was a pleasure to help you.

....happy fly from Peru.

(edited by moderator)

This nav offset looks like it is from the STAB_PITCH_DOWN parameter.  According to the wiki this is a pitch down applied to the plane in FBWA when the throttle is below TRIM_THROTTLE.  This is meant to help maintain airspeed when hands are off. 

Hope this helps

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