If you encounter any hanging/unresonsiveness issues with YAACARS, try to:

• disable Windows “Gaming Mode”
• DON’T run it from “c:\Program Files” or similar windows-managed locations
• run it with administrator privs
• run it with legacy support for “Windows XP” or “Windows Vista”

It seems that this aircraft uses internal fuel tanks. Only default LEFT MAIN and RIGHT MAIN are used and visible to YAACARS

Might still be a bug - didn't investigated further. Found on the web: https://fsuipc.simflight.com/beta/Offset_Mapping_PMDG737NGX.pdf Acoording to this document, the 737 has LM/C/RM tanks, but also it's own datarefs to read the tanks …

• Fuel can only be loaded with Fuel Truck connected
• Payload can not be applied (as far as we tried)

• From version 2.0 on YAACARS detects “refuelling” and “defuelling” so your fuel tanks (in FTW) will be empty within a very short time!

=⇒ try to start the flight in YAACARS after the APU has been shut down and finish the flight before turning on the APU back on