I have downloaded the IFly 747-400 and the SP1. I have also read/referred to the 300+ page manual.But, I am stymied trying to set up the FMC/CDU, when I get to the page entering the Gross Weight and the Zero Fuel Weight. No matter what I enter, I get a message saying "INVALID ENTRY". :-(Can someone help me out here - or refer me to a step-by-step guide?Thank you.CVJ

Got the answer straight from the developer:"The ZFW is 406.1 (pound*1000) or 184.2 (kg*1000). You can switch between Metric System and US System. (CDU->SIMU->SYSTEM UNITS).Best regardsJiangwei Shen"Tried it and it works -

Disregard. Sorry.