Definition
A turn of 180 degrees of heading, reversing the aircraft's direction of flight. In instrument flying, it is a standard escape maneuver used to retreat from deteriorating weather, icing, turbulence, or other hazardous conditions back to the better conditions the pilot just came from.
Plain English
A half-circle turn that points the aircraft back the way it came. It is the simplest, most reliable way to get out of trouble, because the air behind you is the same air you just safely flew through.
Context Anchor
Seen in instrument flying when a pilot needs to reverse course, such as turning away from weather, terrain, or a condition that is making continued flight unsafe.
Derivation
A full circle has 360 degrees, so 180 degrees is half of a circle. In heading terms, a 180° turn means moving halfway around the compass to the opposite direction.
Why Pilots Care
Allows a safe reversal of direction under instrument conditions when continuing on course is not viable.
Intuition Check
A 180° turn does not mean any large or dramatic turn. It specifically means a half-circle change in direction, ending on the opposite heading.
Example Sentence 1
When the cloud bases dropped lower than forecast, the pilot made a 180° turn and returned to the departure airport.
Example Sentence 2
Under the hood, the student completed a standard-rate 180° turn to practice returning to the departure airport in IMC.