Thanks for posting that pic of the -420. BTW, it's available with or without the stairs, depending on the era you want to model (i.e. with or without jetways).
(I had to break the long line into 4 to get it to print here).
To use it in Ttools you would need to change "AC#19004" to whatever you have numbered the aircraft in the Aircraft.txt file...In addition, the plan now goes through Kai Tak instead of Chek Li Kok so to put it back then change VHHX to VHHH.
Also it calls in at McLeland Field so if you don't have that then change PAMA to PAYA and then it will route through Yakutat instead :flying:
As a bonus, some of the other textures available at HJG for the Boeing 707-320 seem to fit this model OK. Which is great news for my Kai Tak 70s/80s project: