[Bug] 1.15.X VTOL mission mode, TransitionToFw issue.

[liu12344321]

Describe the bug

When uploading a mission to the Holybro 6C flight controller that includes a takeoff and a transition to fixed-wing flight, as shown in the diagram,

the following occurs:
1.After arming and starting the mission, the drone progresses to the first waypoint, marking mission progress at step 1.
2.At the second waypoint, during the fixed-wing transition （before transition finished）, manual stick input interrupts the mission, forcing the drone to land.
motors output as show in diagram below:

3.After landing, re-arming and restarting the mission results in the drone immediately spinning the tail motor on the ground instead of taking off with the rotors.
motors output as show in diagram below:

motor5 is tail motor.

I tested 1.14.X and found that this issue does not occur. When restarting the mission, the drone first takes off using the rotors and then transitions to fixed-wing flight as expected.

To Reproduce

No response

Expected behavior

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Screenshot / Media

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Flight Log

The first time the mission is executed:https://review.px4.io/plot_app?log=b1c35e13-64d5-4f78-9c34-a8d79175522a
After landing resume the mission:https://review.px4.io/plot_app?log=9dd0aa00-37e2-498d-9207-b0651bba6f7d

No response

Software Version

1.15.2 and 1.15.1

Flight controller

Holybro 6c mini

Vehicle type

Hybrid VTOL

How are the different components wired up (including port information)

No response

Additional context

No response

[DominicMarti]

Hi @liu12344321

Not sure how much that helps but I have seen something similar in the past regarding the spinning up on second round.

Can you please double-check something first to see if it is the same thing. Please trigger the same behaviour of forced landing after interrupting the front transition with a stick input. But this time, before re-starting the mission, re-upload it again to the pixhawk through your UI (QGC or whatever you use) and then start. If it is what I think it is, this will "solve" the problem and will start the mission from scratch.

If that works out, the problem is that the mission is not reset after the rally point landing/landing on ground. For all other waypoints, this behaviour is somewhat intended as you might want to continue with the mission without reupload from the waypoint the mission was interrupted. But for the front transition and VTOLs, this is actually pretty dangerous.

Now for the solution, I can provide some of the "hacky" ideas we used at the time. We forced the purging of the mission after every disarm, making sure the mission is uploaded anew before the next takeoff. I consider this a safe solution as in our use-case we never wanted to continue the mission after an emergency landing without the operator deliberately overriding the mission. More elegantly, one could handle the special case of front transition abortion and purge the mission just in this case after disarming.

Let me know how it goes. If the issue hasn't been fixed yet in the official release, I might be able to help to find a solution in the code.

Cheers!