Definition
Ground boosting is the use of a turbocharger or supercharger to raise the engine's manifold pressure above standard sea-level atmospheric pressure while operating at or near sea level, producing more power than a normally aspirated engine of the same displacement could produce at that altitude.
Plain English
The engine is fitted with a turbocharger or supercharger that pushes extra air into the cylinders even on the ground, so it makes more power down low than a regular engine of the same size.
Context Anchor
Seen in discussions of turbocharged airplane engines, takeoff power settings, manifold pressure limits, and the difference between boosting power near the ground and maintaining power at altitude.
Derivation
Boosting' refers to forcing extra air into the engine to raise manifold pressure above ambient. 'Ground' specifies that this extra pressure is being produced while still at low altitude, where the surrounding air is already dense.
Why Pilots Care
Determines how much extra takeoff and climb power is available in a turbocharged piston aircraft and how that power changes as altitude increases.
Grounding Statement
On takeoff from a low-elevation airport, ground boosting can help the engine make more power than it would by breathing outside air alone.
Intuition Check
Ground boosting does not mean a ground crew is helping the airplane. It means the engine is being pressure-boosted while the airplane is still at low altitude, including takeoff.
Example Sentence 1
Because this engine is ground boosted, it produces strong takeoff performance but loses power steadily as we climb.
Example Sentence 2
Unlike altitude turbocharging, ground boosting provides additional power right from the surface before the aircraft climbs.