Does UFOB equal BLOCK minus BLST?I ask this because in the FMS manual downloadable from smartcockpit.com, there's a weight init page with a BLST value (LSK3R) defined where BLOCK and UFOB (LSK1R) both have the same amount...

No. No connection.BLOCK is how much you put it 'in this block'. Ballast is how much fuel you have on board for ballast purposes only. UFOB is how much unused fuel you have on board. You add BLOCK to the UFOB you landed with to ensure you have enough for the next leg. You ballast if you are underweight for the next leg so you can safely manage CoG (repositioning flights etc.).If your UFOB drops below your expectation, find out why! You are burning more then expected or you are leaking!

(old post I know, just correcting it for future readers).No, BLOCK has nothing to do with how much fuel you currently have on board. UFOB is how much fuel you have on board (useable fuel on board). "Ballast" is extra fuel loaded for balance/handling but not actually consumed for the trip.BLOCK is a "test case" input field to the convenient fuel calculator on that page. After entering your flight plan, cargo/pax, and weather info, you can test different fuel scenarios by entering a proposed fuel amount into BLOCK and reading if you have any extra fuel or extra flight time in the EXTRA/TIME field at the bottom of the page. Once you get near a 0/0 EXTRA/TIME result load the plane with whatever you entered into BLOCK. In other words, load fuel so UFOB equals the magic number found in BLOCK.The reason the tutorial "quick copies" UFOB into BLOCK is so that you can double check UFOB is enough to get you there.Clark

Balast is used only when or heavy (will do it automaticly) or with wrong loading.Cheers,John