Question 1

What reserve time should I use?

Accepted Answer

For IFR flight plans, the FAA requires enough fuel to reach the destination, fly to an alternate, and then fly for 45 minutes at normal cruise. VFR rules require 30 minutes (day) or 45 minutes (night) of reserve beyond the destination. Always use the requirement for your flight rules.

Question 2

Why does ground speed matter more than airspeed for fuel planning?

Accepted Answer

Fuel burn is measured in lbs per hour, not lbs per mile. If a headwind increases your flight time, you burn more fuel even though your TAS and burn rate are unchanged. Always enter the ground speed you expect, factoring in forecast winds for the route altitude.

Question 3

The calculator uses lbs - what if my aircraft uses gallons or kg?

Accepted Answer

Avgas weighs approximately 6 lbs per US gallon. Jet-A weighs approximately 6.7 lbs per US gallon (varies with temperature). For kg, divide lbs by 2.205. Use consistent units throughout - enter burn rate and read results in the same unit.