PMDG 737-700 refuses to taxi after replay (N1 = 80% makes it move suddenly)

[till213]

Describe the bug
When trying to resume taxi [after replay has stopped], the plane seems to be stuck on the ground. I have checked everything to the best of my knowledge and I don’t see anything that could be causing this like auto or parking brakes applied for example. The plane will only move when N1 is around 80%.

To Reproduce
Here is my flow:

• Few minutes before landing, I start recording
• Right after leaving the runway and STOPPING any plane movement, I stop recording
• I drag the slider back to a point where the plane is very close (2 to 3 seconds) to the touchdown moment
• Play
• Pause
• Set camera so I can see my landing from the runway with a stationary camera (Drone with ‘Drone Follow Mode’ OFF and ‘Drone Lock Mode’ ON)
• Drag the slider back a bit more (until the plane is +/- 1 minute prior to the touchdown moment)
• Unpause and enjoy :slight_smile:
• Usually, after touchdown, I drag the slider back until the plane is +/- 1 minute prior to the touchdown moment, let it play, and move the drone to see the landing from a different view point. I use to do this multiple times.
• When done, I just drag the slider to the end or wait till it gets there

This all works superbly well. However, when trying to resume taxi, the plane seems to be stuck on the ground. I have checked everything to the best of my knowledge and I don’t see anything that could be causing this like auto or parking brakes applied for example. The plane will only move when N1 is around 80%. At that time, something ‘unlocks’ the plane and - as you can expect - it moves forward as a rocket.

I have tried different things without success:

• After leaving the runway, stopping the plane, and before stopping recording, I confirmed the brake (be it auto or parking) was NOT applied.
• I completely ignored step 2, that is, I went to step 3 when the plane was still on the runway moving at around 30kts or so. Much better this time because I can keep the plane moving by applying just a bit of thrust (the normal condition). However, if for whatever reason I have to stop the plane during taxi, I cannot make it move anymore unless I apply 80% N1.

I can be wrong here (as this is frequently the case :slight_smile: ) but it seems to me Sky Dolly is not ‘restoring’ something when it is done replying the sequence. At least in my setup.

Expected behavior
The aircraft can be controlled normally after replay has stopped.

Application version:

• Visible in the "Info / About" dialog
• (Presumably) version e.g. 0.15.0

[till213]

This is quite strange: the usual suspect in such a case ("aircraft does not move anymore after replay") is that an "unfreeze" has been forgotten.

Sky Dolly (and other tools) typically "freeze" the aircraft for replay, in order to completely control the aircraft position and such that the simulation does not try to "counter-act" ("simulate") the simulation variables and events that are being sent to MSFS during replay. Of course after the replay has stopped the user aircraft is to be "unfrozen".

However in such a case ("aircraft still frozen") the aircraft would not move at all, specifically not even when increasing the thrust ("N1 = 80%"). So there must be something else going on.

I suspect that something "gets mixed up" in the given aircraft simulation logic, especially after you are shutting the engines down (at least that is my assumption here, however it is not quite clear whether "STOPPING any plane movement" also includes shutting down the engines). Sky Dolly actually does support "start from cold and dark", simply by sending an "auto-start engines" event as needed (if Sky Dolly detects that the engines are shutdown) - but whether that works repeatedly - and reliably - with every given aircraft is beyond the control of Sky Dolly.

In case the engines are not shutdown then perhaps there is some other aircraft-internal variable "getting confused" - but this should not happen, of course, based on the standard "simulation variables" that are sent to the aircraft.

However once I get to it I will try to reproduce this behaviour, and see whether recording additional simulation variables might help. But that's just a wild guess at the moment...

[Sylpro7]

Hello, I have exactly the same bug with my PMDG 737-800. If it can give you a hint to fix that.... Everything comes back OK if I replace de tires into the ground maintenance of the plane ... ???