Definition
A standard instrument turn rate of 1.5 degrees per second, which completes a full 360-degree turn in four minutes. It is half the rate of a standard rate turn (3 degrees per second) and is typically used by aircraft operating above 250 knots, where a standard rate turn would require an excessive bank angle.
Plain English
A slow, steady turn that takes four minutes to go all the way around in a full circle. It's used by faster aircraft because turning more quickly would require banking too steeply.
Context Anchor
Seen on the face of some turn-and-slip indicators, especially in aircraft where slower turn-rate indications are used for instrument flying.
Derivation
Named directly for the time it takes to complete a full 360-degree turn at this rate. The convention parallels the more common 'standard rate turn' (also called a 2-minute turn), which completes a circle in two minutes.
Why Pilots Care
Provides a consistent, predictable turn rate for timed turns and instrument procedures when the aircraft is equipped with a turn-and-slip indicator rather than a turn coordinator.
Grounding Statement
The marking is about how fast the airplane is changing direction, not how long the pilot must keep turning in every situation.
Intuition Check
Do not read 4 MIN TURN as an instruction to turn for exactly 4 minutes. It means the turn rate is slow enough that a full 360-degree circle would take 4 minutes if continued.
Example Sentence 1
Flying the jet at high altitude, the pilot used a 4 minute turn to keep the bank angle manageable while maneuvering on the airway.
Example Sentence 2
To reverse course in the holding pattern, the pilot used a 4 min turn to the left.