Thud mentioned that he was wondering about what we did to manage our fuel and I didn't have an answer for him. I tried to find some info in the NATOPS manual but my eyes rolled back into my head after the first 100 pages! I googled it and found this on hoggit:
I've been planning my fuel for custom missions and so far have a decent system that seems accurate so far:
Work backwards from recovery, to bingo, to joker, to total mission fuel requirements.
Minimum recovery fuel: 2000 - 2500 pounds for carrier recovery depending on your confidence. 1200 pounds for field recovery.
Bingo: Figure out the farthest distance from recovery the flight plan will take you. For example, 80 nautical miles. Now you need to figure out how much fuel it will take to get back from there. Optimal fuel efficiency cruise is 5.6 degrees AOA according to NATOPS, which I've found is usually around 400 knots ground speed and 5000 pounds-per-hour at high altitude (over 20,000 ft). So, at 400 knots ground speed, you'll traverse 80 nautical miles in 0.2 hours, and over 0.2 hours you'll use 1000 pounds of fuel. Add a "fudge" amount on top of that for high-powered climb to cruise altitude, and to take into account errors so you're on the safe side. So say cruise to recovery is about 1500 pounds. Add that to your recovery fuel to get your bingo: 3500 - 4000 pounds depending on your confidence in carrier landings. This is the number to enter on your IFEI.
Next, we need to figure out Joker, which is the fuel required to perform the mission and return to base. Start with the bingo value, say 3500 pounds, and try to estimate how long the mission itself will be. Will you be dogfighting and using burner a lot? Is it a one-pass strike? I usually like to reserve about 2000 pounds for this if I anticipate a minute or so of burner, but you may need a lot more if you'll be loitering doing CAS. This number is highly variable. Add that number to your bingo and you have Joker. In this case let's say 2000 pounds is needed for the mission, so our Joker is 2000 + bingo, which comes out to 5500 pounds. Note this in the mission briefing.
Finally, calculate takeoff and cruise to the target area. I like about 500 pounds for takeoff itself, which covers idling, taxi, and liftoff. And you'll need to account for the climb to cruise altitude, if you're doing so, which might be another 500 pounds. Finally, your cruise to the target area: use the same calculation we did from bingo but take your waypoint route distance into account, not the direct "as the crow flies" distance. A fast low-level trip will obviously have a different speed and fuel flow. You'll have to do some math. Let's say for example we came up with 1500 pounds of fuel for your entire route to the target. Add this amount and your takeoff and climb figures to your joker amount. In this example, 1500 pounds for cruise, and 1000 pounds for startup, takeoff, and climb to altitude. 2500 pounds plus the 5500 joker fuel comes to 8000 pounds of mission fuel. This is the fuel amount to fill your jet with at mission start.
These are just example numbers, but you get the idea. It's never a bad idea if you're unsure of a number to overestimate the fuel by a bit, I like to use 500 pounds as a "fudge number" to add in when I'm unsure of what I'll need. But it's not too hard, and you just need to do it once at the start of a mission.
