ADDED a new new option in the Advanced Options section named 'Use PF3 Thread'. This is off by default and setting it to 'on' results in all taxi routing calculations to/from the runway being handled by a separate external thread from PF3. Why should you want to use this? Well for some larger airports, especially in MSFS, you can sometimes find it can take quite a while to receive your taxi instructions. This can be caused by a variety of reasons... your parking position relative to the active runway... distance to the active runway... inaccurate AFCAD taxiway data, to name but a few. You may, at times, even think PF3 has stopped working or become stuck in a loop, because during the calculation of the taxi route PF3 is unable to do anything else, as it's a single threaded program.
When using an external thread we are able to provide some kind of feedback from ATC to let you know you haven't been forgotten. The first message will be a simple 'callsign, stand by' which will occur approximately 5 seconds after your request for taxi instructions. We set this to 5 seconds because the majority of calculations are complete within 5 seconds. The next thing you'll hear from ATC if the calculation is taking longer is at around 1 minute when ATC will say 'callsign, standby, with you in 5'. Now this doesn't actually mean you will definitely have to wait a further 5 minutes because in truth we have no way of knowing how long the calculation is going to take, but you shouldn't be waiting any longer than that.
There is a fail safe trigger in place that kicks in at around 6 minutes, at which point PF3 would revert to our backup process which will ensure you at least get cleared to taxi even if it's a simple 'callsign, taxi to blah, blah'. So, in summary, if you've never experienced a long wait or if it doesn't bother you at all, you can just leave this option off. The other reason we included an option for this switch was some beta testers found the external thread caused problems on their system. So the choice, as they say, is yours. Personally, I always have the option 'on'