Version 1 May 2006
To calculate fuel use (eg, how many litres in one hour, or how many minutes a certain number of litres will last).
Question: You launch with a total of 90 litres of fuel. After 20 minutes you estimate there are 75 litres remaining. How many litres will you use in one hour? How much longer can you fly if you are to land with 30 minutes of fuel still remaining?
15 (90 – 75)
= 15 divided by 20 multiplied by 60 = 45 litres per hour
Step 2: The total flight time if all 90 litres of fuel is used is found from the following square. Use the same basic information as above that 15 litres lasted 20 minutes.
= 20 divided by 15 multiplied by 90 = 120 minutes
Total time to zero fuel is therefore 120 minutes. You have already been flying 20 minutes, and you must land 30 minutes before getting to zero fuel, so your remaining flight time is
120 minus 20 minus 30 = 70 minutes.
Rate of climb or descent
To calculate rate of climb (or descent) using time
Question: What rate of climb is required to ascend 2,000ft in 5 minutes?
(distance in ft)
(time in mins)
ABF Pilot Training Manual Part 8
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