Plain English Meaning

A turbocharger kit added to an aircraft engine after it was built, rather than coming from the factory that way. It lets the engine keep producing more power up high, where the air is thin.

Full Definition

Turbocharging systems installed on a piston aircraft engine after the airplane has left the factory, typically through a Supplemental Type Certificate (STC). These systems use exhaust-driven turbines to compress intake air, allowing the engine to maintain rated power at higher altitudes than it could naturally aspirated, but they are added to an engine that was not originally designed or certified with turbocharging built in.

Context Anchor

Seen in discussions, aircraft records, and operating instructions for aircraft that were fitted with a turbocharger after original manufacture.