While in midflight, esp on longhauls flights, heres what i do to fig out if I'll have enough fuel for the remainder of my flight.
Pull up your clock and start it for one minute-to the second. (ie-8:44:07 and stop it at 8:45:07)Giving you 60 seconds.
Write down how many lbs of fuel is left in the tanks.
You will see how many lbs of fuel burnt in the 60 seconds.
Jot down your FF
per hour, mileage to destination and fuel left in weight., BEFORE & AFTER.
#'s are examples: 7,900 lb/hr (times 4, for a 747=31,600lbs/hour or 526.6 lbs of fuel per minute)
8 miles traveled in 60 seconds, and 4680 miles to go till destination /by 8miles per minute=585 minutes.
287,900 lbs of fuel in the tanks. OK
, stay with me. Divide 287,900 by 526.6 min's=547 minutes. Guess what? I need at least 585 minutes of fuel so I'm short by 38 minutes. But, I have plenty of time to throttle back and use less fuel and I'll make my destination without "cheating" to add fuel.
I hope this wasnt TOO complicated.