Preflight fail and aircraft not ready

PX4 Autopilot
1

Hello everyone,
I’m trying to control a Cessna 172 in X-Plane 11 using QGroundControl. I’ve followed all the steps shown in YouTube tutorials and on GitHub. Everything runs as expected—except for actually flying the Cessna 172.

In the px4xplane running on WSL, there’s always a preflight failure. In QGroundControl, I frequently encounter issues related to vertical velocity, and sometimes with position or altitude, which causes the “Not Ready” message to appear in the bottom-left corner of the screen. As a result, the only flight mode I can use is Manual mode.

I’ve also attached an image to show the issue I’m encountering.

Thanks in advance for any help or suggestions!

I use:
-Xplane 11v55r2 running on win10
-Qgroundcontrol running on win10
-PX4 running on Ubuntu in wsl

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received_10489674571462661583×847 324 KB

received_2125133327990810
received_21251333279908101910×997 144 KB

2

The warning “Preflight Fail: ekf2 missing data” means that the EKF2 isn’t consistently getting data. And that likely explains the various messages regarding states getting “unstable”.

You will have to look into why you have drops like that. Does your computer have enough CPU/GPU to keep things running smooth? If not, that could be the reason.

I’m not familiar with X-Plane, so it could just be an inherent problem with X-Plane not giving consistent sensor data in terms of timing.

If there is no way around, you will have to adjust EKF2 parameters and raise threshold that are triggered, in order to be able to arm and use modes other than Manual.

3

Thanks for your help! I will check and get back to you with feedback

4

Hello, sorry for the late reply. You were right — the “Preflight Fail: EKF2 missing data” issue was related to CPU/GPU performance. I ran X-Plane 11, PX4 Autopilot, and QGroundControl on a more powerful laptop, and everything worked normally at first. However, after a few minutes, the laptop heated up and all the warnings started to appear again.
Do you think I should buy a gaming laptop just to run X-Plane 11 or 12, and use a separate one for PX4 and QGroundControl?

5

Check CPU/GPU and what the bottleneck is. I don’t know. I’m personally not a fan of gaming laptops and would go with a desktop setup but that’s up to you.

6

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