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## Help

• Posts: 10

### chanejane created the topic: Help

Hi bob
Need help on the following question
Given the following flight plan;
Useable fuel(excluding reserves) = 115litres
Fuel flow = 28litres per hour
Ground speed = 95kts
The maximum distance that can be covered is closest to:
(a) 390nm
(b)155nm
(c)205nm
(d) 350nm

My calculation as follows:
60 x 115=6900/28=246nm

Appreciate yr help.
Thanks
Jane

• Posts: 1962

### bobtait replied the topic: Help

The question says that the usable fuel available is 115 litres and that excludes reserves. So you have 115 litres of flight fuel - you can burn all of that. At 28 litres per hour that means you can fly for:
115 ÷ 28 = 4.1 hours.
Your ground speed is 95 knots so at 95 knots for 4.1 hours you can fly:
4.1 x 95 = 390 nautical miles.

Another approach is to find the ground nautical miles per litre. In each hour you cover 95 miles and you burn 28 litres so how far does each litre take you?
95 ÷ 28 = 3.39 miles per litre.
You have 115 litres to burn and each litre takes you 3.39 nautical miles so you can fly
115 x 3.39 = 390 nautical miles.