Definition
A turn rate of 1.5 degrees per second, which is half of the standard rate turn of 3 degrees per second. At this rate, a 360-degree turn takes four minutes to complete. Half standard rate is commonly used in high-performance and turbine aircraft above approximately 250 knots, where a full standard rate turn would require an excessive bank angle.
Plain English
A gentle, shallow turn — half as quick as the normal turn rate pilots are taught to fly on instruments. It takes four minutes to turn a full circle instead of two.
Context Anchor
Seen in instrument flying when using the flight display’s turn-rate cues to control how fast the airplane is turning.
Why Pilots Care
Helps maintain altitude and airspeed more easily during turns and reduces the chance of overshooting a desired heading.
Grounding Statement
If the airplane starts on a north heading and holds a 1/2 standard rate turn, it will point roughly east after one minute.
Intuition Check
Do not read “standard” as simply meaning “ordinary” or “good enough.” In this context, “standard rate” is a specific measured turn rate, and “1/2 standard rate” means half of that measured rate.
Example Sentence 1
Above 250 knots, the crew flew the holding pattern at half standard rate to keep the bank angle reasonable.
Example Sentence 2
In moderate turbulence the instructor called for a 1/2 standard rate turn to stay within heading tolerances.