RC Loss failsafe Return mode not working in POS/ALT HOLD or MANUAL flight mode

PX4 Autopilot Flight Controllers 💻
1

Firmware PX4 v1.11.0 Beta 2

When the drone is in POS/ALT HOLD mode with RC Loss failsafe Return mode enabled the drone is not returning to launch but instead lands at the position it is in at that moment.
When in manual flight mode it drops out of the sky with RC loss.

Expected behavior
When switching off the transmitter the expected behaviour is that the drone does a RTL.

Log Files and Screenshots
https://logs.px4.io/plot_app?log=4da4f3fa-5d46-4eee-8277-18484df00a20

Add screenshots to help explain your problem.

Drone (please complete the following information):
Airframe: HolyBro QAV250
Quadrotor x (4052)
Hardware: PX4_FMU_V5 (V540)
Software Version: v1.11.0 (beta) (2bbdef2)
OS Version: NuttX, v8.2.0
Estimator: EKF2

2

Thanks for the test and issue.

I’m not sure I’m looking at the correct log. In the log I see that you lose RC only very briefly twice, first at 4:22.8 and second at 5:16.95.

Both times, according to the log, it goes into RTL. I’m not sure if your RC detection is not working properly or if you uploaded the wrong log.

3

Hi Julian,

I think it’s the correct log, Because I tested it twice.
The first time was when on pos/hold when I turned of my transmitter, de drone was landing on the location it was at that moment and did not do an RTL.
The second time was on horizontal mode, than when I turned of the transmitter the drone dropped from the sky, so that’s a really bad thing.
I believe I set the failssafe settings correctly in QGC.
I’m not sure what you mean by RC detection, I use a Futaba compatible sbus receiver.
If you need any information more or if you want me to test it and log it again please let me know.
Thanks for the help!

4

Can you tell me at which times (in the log) you switched off your RC?

5

I think the times you said already first at 4:22.8 and second at 5:16.95.
If you want I can test it again, and write down the exact times, please let me know.

6

But RC lost only happens for 1 sample, so probably less than a second.

7

Ok so to be 100% sure I’ll test it again, horizon mode and hold mode, I will switch off my transmitter on both occasions and send you the new log file again.
I can only test it when it’s not raining, so please be patient.

8

Before you fly, make sure that RC loss is configured correctly by switching it off on the ground and checking if it is correctly notified in QGroundControl.

Also see: https://docs.px4.io/master/en/config/radio.html#rc_loss_detection

9

Hi, your right, the RC loss detection is not setup right, so I will read about it and set it up properly, thanks for the help!

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