When it’s time to do your flight planning, be sure to calculate your minimum fuel requirements according to the rules – identify the flight course and distance, apply normal cruise power settings for the particular aircraft, and consider timely weather reports to calculate the fuel needed to complete the planned flight. Then make sure to identify the correct reserve amount you’ll need for your particular flight. For VFR flights, FAR 91.151 requires that you depart with enough fuel to complete your flight, plus enough fuel to fly for 30 more minutes if during the day, or to fly for 45 minutes if flying at night. In a rotorcraft, you’ll need enough fuel to fly for 20 more minutes, day or night. For IFR flights FAR 91.167 requires that you depart with enough fuel to complete your flight, plus fly to an alternate airport, plus fly after that for 45 minutes (or 30 minutes if you’re in a helicopter). You are permitted to eliminate the alternate airport in your calculations if the destination airport has a standard instrument approach procedure and the reports and forecasts for that airport indicate that the ceilings will be at least 2,000 feet above airport elevation and visibility will be at least 3 statute miles, both for one hour before and one hour after the estimated time of arrival.
