It's a PMDG-only problem, which could be solved easily if they just checked if GSX is Pushing, like other 3rd party airplanes from FS Labs, Aerosoft, Leonardo do. The issue is:
- PMDG has some kind of internal simulation of the steering which constantly acts on the gear/rudders, so it fights against the GSX one, causing the rudder to shake, since both are trying to write to the same variable. In real life, during Pusbhack, the Bypass pin would disconnect the airplane hydraulic steering from the nose gear, so the Tow truck could turn it freely, and so any custom airplane code that does that should also be temporarily disabled while pushing.
- It was recently discovered by an user that, pressing Shift-P after the pushback started stopped the vibration, most likely because PMDG IS detecting the default pushback, so they *are* pausing their custom code in that case.
So, we just added an option for those airplanes, named "Pushback Dummy Event", which does just that: is sending a Shift-P event to the sim when the pushback starts, and another one when the pushback ends, and that's what is causing that "drift" at the end. Also, is not perfect because, even if this solved the rudder shaking, is still causing some small vibrations, since now GSX must fight against the default pushback.
This way, you have the option to either use that option in the airplane configuration dialog ( by default is enabled for PMDG airplanes ), so you will not have the rudder shaking, but it will drift at the end, or you can disable it, so GSX will not send those keys any more, which will fix the drift, but will result in the rudders shaking in the VC.
Of course, the proper way to fix this, would be that PMDG would detect the GSX pushback just as they are detecting the default one, and turn off whatever system they need, which is how FS Labs, Leonardo and Aerosoft, which all have some kind of custom ground steering, are doing.
