S Turns
S-turns is a ground reference maneuver in which the airplane's ground track resembles two opposite but equal half-circles on each side of a selected ground-based straight-line reference. The maneuver requires arriving at specific points on required headings.
With the airplane in the downwind position, the maneuver consists of crossing a straight-line ground reference at a 90º angle and immediately beginning a 180º constant-radius turn. Bank angle and roll rate are adjusted for drift effects and changes in groundspeed. The straight line is re-crossed in the opposite direction just as the first 180º constant radius turn is completed.
The first 180º constant-radius turn is immediately followed by a second 180º turn in the opposite direction.
If the straight-line ground reference is of sufficient length, the pilot may complete as many S-turns as can be safely accomplished.
Airman Certification Standards
- Select a suitable ground reference area, line, or point as appropriate.
- Enter perpendicular to the selected reference line, 600 to 1,000 feet AGL at an appropriate distance from the selected reference area
- Apply adequate wind-drift correction during straight and turning flight to maintain a constant ground track around a rectangular reference area, or to maintain a constant radius turn on each side of a selected reference line or point.
- Reverse the turn directly over the selected reference line; if performing turns around a point, complete turns in either direction, as specified by the evaluator.
- Divide attention between airplane control, traffic avoidance and the ground track while maintaining coordinated flight.
- Maintain altitude ±100 feet; maintain airspeed ±10 knots.