Definition
Operating a turbocharged or supercharged engine at a manifold pressure higher than the maximum approved by the engine manufacturer, which can damage internal engine components such as pistons, cylinders, and bearings.
Plain English
Pushing the engine harder than it is designed to handle by allowing too much pressure into the cylinders, which can cause serious engine damage.
Context Anchor
Seen in constant-speed propeller operation when coordinating the throttle and propeller controls, especially during power changes, climb, and cruise setup.
Derivation
From 'over' (beyond, in excess) plus 'boost' (the extra manifold pressure produced by a turbocharger or supercharger). Boosting refers to forcing more air into the engine than it would draw in naturally, so over-boosting simply means forcing in more than the engine can safely handle.
Why Pilots Care
Exceeding the limit can cause detonation, cylinder damage, or sudden engine failure.
Grounding Statement
The key idea is pressure: over-boosting means the engine intake pressure is too high for the RPM or limit being used.
Intuition Check
Over-boosting does not just mean using high power. It means the pressure is too high for the engine limit or for the RPM selected.
Example Sentence 1
The pilot advanced the throttle slowly on takeoff to avoid over-boosting the turbocharged engine.
Example Sentence 2
With the constant-speed propeller still at low RPM, an abrupt throttle increase produced over-boosting and triggered detonation.