Time And Fuel Planning
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Getting to where you want, at a certain time, and with a certain amount of fuel, is a challenge that you will face in most missions. This article provides some tools and rules-of-thumb you may use to make this easier.
Distance
Rules-of-thumb:
- Going 5 nm at 300 kts ground speed (GS) takes 1 minute. This roughly translates to 250 kts indicated airspeed (IAS) depending on wind.
- Going 100nm at 20.000' and an airspeed of M0.65, takes around 15 minutes.
Fuel
Fuel Ladder
A common technique, primarily used in the Navy (but can be used regardless of aircraft) is to keep track of the fuel using a fuel ladder. The fuel ladder starts with a (landing) time and a minimum desired fuel state for that time. For instance, 3000 lbs at 12:00. Then it goes backwards in time in 15 minute steps, and adding the fuel 15 minutes of flying in Max E (max endurance) burns. This means that if your fuel state reaches the state indicated for the current time, you will NEED to fly at max E for the rest of the sortie, in order to not having to make your first landing attempt with less than desired fuel (or go to the tanker and refuel, to fix it). For the Hornet, the amount of fuel 15 minutes of Max E flying burns, is 1200 lbs. In the mission planning, make a note on when you're expected to land. Decide what fuel state is needed. For CASE 1 carrier ops, 3000 lbs is what we typically use. For runway landings, 2000 lbs might be enough. Simply add 1200 (or whatever your aircraft of choice burns per 15 minutes) for each row, and complete the fuel ladder. Have it in your kneeboard, and crosscheck it every once in a while, to make sure you have enough fuel.
Example (90 minute sortie):
TIME | STATE 1200 | 3000 1145 | 4200 1130 | 5400 1115 | 6600 1100 | 7800 1045 | 9000 1030 | 10200
