Which unit is used to express a standard rate turn?

• A. Radians per second.
• B. Degrees per minute.
• C. Radians per minute.
• D. Degrees per second.

Answer: (D)

A standard rate turn is defined by a specific angular speed around the vertical axis: 360 degrees in 2 minutes, which equals 3 degrees per second. Since we’re expressing how fast the turn is changing the airplane’s heading, the natural unit to use is degrees per second. In aviation practice, the turn rate indicator is calibrated in degrees per second, and a standard-rate turn corresponds to about 3°/s, completing a circle every 2 minutes. While you could describe the same rate in radians per second or convert to degrees per minute (180°/min), the established and most practical unit for a standard rate turn is degrees per second.