An adjustable-pitch propeller is defined as which?

• A. A propeller whose pitch can be adjusted on the ground with the engine not running
• B. A propeller with fixed pitch
• C. A propeller whose pitch is adjusted in flight
• D. Sometimes used to refer to constant-speed propellers adjustable in flight

Answer: (C)

An adjustable-pitch propeller is defined by the ability to change the blade pitch, which is the angle of the blades relative to the oncoming air. This adjustment is typically done during flight to optimize performance across different speeds and power settings. By changing pitch in flight, you can increase thrust for takeoff or climb or optimize efficiency at cruise without changing engine speed.

Ground-only adjustment isn’t the defining feature, and a fixed-pitch propeller cannot change its angle at all. A constant-speed propeller is a specific type of adjustable-pitch propeller that maintains a set RPM with a governing system, but the basic concept tested is that the pitch can be adjusted in flight to suit conditions.