Emergency fuel shall be declared when estimated to be how much remaining at landing and minimum fuel at how much?

In aviation, the determination of fuel levels is critical for ensuring safety during flight operations. Emergency fuel is declared when the fuel on board is estimated to be at a level that could potentially compromise the safe operation of the aircraft upon landing.

In this context, declaring an emergency fuel level at 6 gallons remaining at landing indicates that this amount is low enough to warrant concern and necessitates immediate action and assistance from air traffic control or other support services. The threshold of minimum fuel at 12 gallons suggests an adequate but cautionary margin that requires monitoring.

The choice reflects a structured approach toward fuel management, promoting safety by establishing a clear definition for emergency situations. This ensures that pilots are prompted to take necessary actions if their fuel levels fall into these critical ranges, thereby reducing risks associated with fuel depletion. In contrast, the other options do not align with common practices regarding minimum and emergency fuel levels, which are typically set at more conservative figures to enhance safety.