What happens to an aircraft's minimum airspeed as it burns off fuel?

As an aircraft burns off fuel, its weight decreases, which has a direct impact on its stall speed. Stall speed is the minimum airspeed at which an aircraft can maintain level flight without stalling, and it is dependent on the weight of the aircraft. As the aircraft becomes lighter due to fuel consumption, it requires less lift to remain airborne. Consequently, the stall speed decreases.

This decrease is due to the relationship between lift, weight, and airspeed. For an aircraft to maintain a stable flight, the lift generated by its wings must equal its weight. With reduced weight, the aircraft can maintain level flight at a lower speed since the required lift diminishes. Therefore, as the fuel burns off and the aircraft becomes lighter, the stall speed decreases, allowing the pilot to maintain control at lower airspeeds.

This concept is fundamental in aviation, as understanding how weight affects stall speed can be crucial for flight safety and performance management.