The excess power () is typically defined as the power available to the aircraft beyond what is needed to maintain level flight. A positive excess power indicates that the aircraft has additional power available, allowing for climbing or accelerating, while a negative excess power suggests that the aircraft is operating at its power limit or might be decelerating. The formula to calculate excess power as follows:
Where:
- : Excess power (Watts or Joules per second)
- : Velocity (meters per second)
- : Thrust (Newtons)
- : Drag force (Newtons)