Definition
The total engine power the aircraft can produce at a given moment under current conditions of altitude, temperature, and engine setting. In climb performance calculations, power available is compared against power required to determine excess power, which directly governs rate of climb.
Plain English
How much power the engine can actually deliver right now. It changes with altitude and temperature — the higher and hotter you go, the less you have.
Context Anchor
Seen in aircraft performance charts and rate-of-climb diagrams, especially where power available is compared with the power the airplane needs to keep flying.
Why Pilots Care
The gap between power available and power required directly determines whether the airplane can climb and at what rate.
Analogy
It is like having extra strength left after carrying a load on level ground. If all your strength is already being used just to keep moving, there is little or nothing left for climbing a hill.
Intuition Check
Power available does not mean any power the pilot wishes the airplane had. It means the usable power the aircraft can actually produce in the current conditions.
Example Sentence 1
At 8,000 feet on a warm afternoon, the power available was noticeably less than at sea level, which is why the climb rate had fallen off.
Example Sentence 2
As airspeed increases, power available gradually decreases while power required rises, narrowing the margin for climb.