What is the minimum fuel supply required for an IFR flight?

The minimum fuel supply required for an IFR (Instrument Flight Rules) flight must ensure not only that the aircraft can reach its destination but also that it has adequate fuel to reach an alternate airport if the destination is not suitable for landing. The correct answer incorporates the requirement for fuel to both the destination and the alternate airport, plus an additional 45 minutes of reserve fuel.

This approach provides a safety buffer in case of unforeseen circumstances such as changes in weather, air traffic control delays, or other emergencies that could affect landing plans. The 45-minute reserve is specifically designed to account for contingencies that may arise after reaching the destination, ensuring that the pilot has enough fuel to safely navigate to an alternative option rather than risking running out of fuel.

Other options focusing solely on fuel to the destination or only including minimal reserve safety do not meet the comprehensive safety standards set for IFR operations, highlighting the importance of maintaining adequate fuel supply for both operational flexibility and safety.