I'm preparing for my EASA exams and one of the questions I came across for the "Flight Performance and Planning" exam sounds like this:
For planning a VFR flight, the following data are given:
Flight time with planning "overhead-overhead" = 2h 43min
Pressure Altitude = 6.500 ft
Temperature = ISA-20
Power setting = 2300 RPM
Taxi Fuel = 2 USG
Additional time for climb = 7 min
Additional time for approach and landing = 10 min
The reserve fuel has to be 30% of trip fuel.
Determine the minimum block fuel:
A. 47.3 USG
B. 50.4 USG
C. 43.8 USG
D. 39.2 USG
The correct answer is B. 50.4 USG.
My thinking was the following:
- Based on the chart and for the given OAT, Altitude I can detect the Fuel Flow of 12,4 GPH
- If I am subtracting 7 min climb time + 10 min approach and landing time, I get a Trip Time of 2h 26min
- Based on The Trip Time and the Fuel Flow I can calculate that the Trip Fuel is ~28 USG
- 30% of the Trip Fuel would be about 8,4 USG, representing the Reserve Fuel
- Adding Taxi Fuel + Trip Fuel + Reserve Fuel = 38 USG
Now, of course, something I am calculating wrong or terrible wrong, for sure, the missing part is the fuel needed for T/O and Landing... but I just don't know how to get that.