AVI310105
Turn Direction
Turn Direction — Which Way to Turn?
Picture This
You are flying at heading 040° when ATC calls:
"QF401, turn heading two-seven-zero."
Should you turn left or right? You could turn either way and eventually reach 270° — but one way is much shorter. In an emergency with aircraft converging, turning the wrong way wastes precious seconds.
On a compass, there are always two ways to get from any heading to any other:
Clockwise (turning right)
Anticlockwise (turning left)
The two arcs always add up to 360°. The shorter arc is always ≤ 180°.
Turn Direction Rule
Calculate the clockwise difference: target - current.
If the result is negative, add 360°.
If the result ≤ 180° → turn RIGHT (clockwise is shorter).
If the result > 180° → turn LEFT (anticlockwise is shorter).
Special Case: Exactly 180°
If the clockwise difference is exactly 180°, both directions are equally long. In practice, ATC will always specify "turn left" or "turn right" so the pilot never has to decide.
Why ATC Always Specifies Turn Direction
In real operations, ATC does not just say "turn heading two-seven-zero". They say "turn left heading two-seven-zero" or "turn right heading two-seven-zero".
Why not let the pilot choose? Because ATC can see other traffic on radar. The shorter turn might send the aircraft toward another plane. ATC picks the direction that is both efficient and safe.
Explore: Turn Direction Simulator
Use the simulator to explore different heading changes. Try different current and target headings — notice which turn is shorter.
Turn Direction Explorer
Compare clockwise vs counter-clockwise turns. Shortest is highlighted green.
Exercise: Turn LEFT or RIGHT?
Determine the shortest turn direction for each heading change.
Determine the shortest turn direction.
Current → Target