Power loss during the flight(mission mode)

I was flying a quadcopter in mission mode and experienced a power loss for about 2,3 seconds. And dropped some altitude. After 2,3 seconds I was able to take the drone into manual control by the RC.
firmware v1.10.1 release. it’s not a customized firmware just stock.

https://review.px4.io/plot_app?log=4b89db19-9520-4654-9c81-b228b7e9a24a

This is the log. I was testing the quadcopter 6,7 times before for around 20 mins flights, nothing like this occurred before.

From my analysis it looks like you had RC lost which made the system switch to stabilized mode with minimum throttle. Usually, when RC is lost, the RC lost action should be triggered and not stabilized mode, so that’s odd.

What RC receiver are you using and connected how?

Could you check if your RC loss is configured and working correctly?

You can see that it switches to Stabilized at 19:36.5.

And therefore all motors drop, which is what you can also see in the current consumption.

Right before that you have a spike in RC lost which might have triggered all of that.

Hi thanks for the analysis, i was using a herelink controller and reciever. At the place there were others flying model airplanes at 2.4 ghz. Could that interfere with the signal?
yeah i will look into it further on how i have configured the rc loss.
Thank you much for the explanation @JulianOes

Interference in the 2.4 GHz spectrum is always possible or to be expected. Often it can be tolerated and if not the RC failsafe should kick in correctly. However, you should never see “wrong” RC values as such in today’s digital transmission signals.

i did two test flights today, same thing happened in the middle of the flight, i had rc loss but it directly went to the position mode. unlike the other day i was flying in position mode before putting it to the mission. in the middle of the mission it went to the position mode after the RC loss failsafe triggered even when it is set to return mode.

https://review.px4.io/plot_app?log=c78386d8-c19d-4081-8ef3-d5731a861c51

https://review.px4.io/plot_app?log=7df5f9ba-458a-4068-9d2e-b2069b26cade

i am quite little confused why this happened, because you asked me i made sure that the rc loss fail safe is set to return mode.
@JulianOes if you got time could you give a peek at the log files. I’m kinda lost.

Have you tried if RC loss is correctly detected when you just on your bench switch RC off or walk far away with RC and shielded antenna? This should be the first step before flying again, I’d say.

You can see that your flight mod spikes for the very first RC loss somehow:

What RC receiver are you using and connected how?

Could you answer that?

I will check that for sure. I’m doing a flight test tomorrow , will bench test the system first as you suggested. Thanks for all the help @JulianOes
RC receiver is , the herelink receiver and it’s controller.
https://www.3dxr.co.uk/product/herelink-hd-video-transmission-system/

Ok, then the question is how the radio signal is transmitted.

it’s 2.4 ghz radio controller, and connects to the sbus RC port. just like normal sbus receiver.

I think i made a workaround by tweaking the rc loss check duration to 1.5 seconds, is it fine or dangerous to tweak it that much? i’m getting expected behavior now. as you suggested i cut off the rc in the middle of a mission, and it performed return to launch as expected.