What is the unit of measurement used by a prop protractor?

• A. Degrees
• B. Radians
• C. Grads
• D. Pulses

Answer: (A)

The unit you read on a prop protractor is degrees. A protractor is a tool for measuring angles, and degrees are the standard unit for most practical angle measurements in aviation maintenance, including propeller blade pitch. Degrees provide a straightforward, widely used scale (0 to 360 around a circle) that's easy to read and apply when setting or checking blade angles.

Radians are used mainly in higher math and physics calculations, not typical field measurements. Grads are an older, less common angular unit, not used on standard maintenance tools. Pulses aren’t a unit of angle at all; they refer to signals from encoders, not direct angle readings. So degrees is the correct and most practical choice for a prop protractor.