Updated: Feb 10
Ground Reference Maneuvers Lesson by wifiCFI
To determine that the applicant exhibits satisfactory knowledge, risk management, and skills associated with ground reference maneuvering which may include a rectangular course, S-turns, and turns around a point.
The applicant demonstrates understanding of:
Purpose of ground reference maneuvers.
Effects of wind on ground track and relation to a ground reference point.
Effects of bank angle and groundspeed on rate and radius of turn.
Relationship of rectangular course to airport traffic pattern.
The applicant demonstrates the ability to identify, assess and mitigate risks, encompassing:
Failure to divide attention between airplane control and orientation.
Collision hazards to include other aircraft, terrain, obstacles, and wire.
Low altitude maneuvering/stall/spin.
Distractions, loss of situational awareness, and/or improper task management.
Failure to maintain coordinated flight.
Ground Reference (AFH C6)
The purpose of ground reference maneuvers is to train pilots to accurately place the airplane in relationship to specific references and maintain a desired ground track.
Such precision requires that a pilot simultaneously evaluate the airplane’s attitude, reference points along the desired path, and the natural horizon.
To be effective, the pilot must scan between several visual references to determine relative motion and to determine if the airplane is maintaining, or drifting to or from, the desired ground track.
Visual scanning across several references allows the pilot to develop the important skill of determining the rate of closure to a specific point.
Drift and Ground Track Control
Wind direction and velocity variations are the primary effects requiring corrections of the flightpath during ground reference maneuvers.
An airplane is traveling at 90 knots (90 nautical miles per hour) and the wind is blowing from right to left at 10 knots. The airplane continues forward at 90 knots but also travels left 10 nautical miles for every hour of flight time. If the airplane, in this example doubles its speed to 180 knots, it still drifts laterally to the left 10 nautical miles every hour. The airplane travels within an often moving body of air, so traveling to a point on the surface requires compensation for the movement of the air mass.
Constant Radius During Turning Flight
In a no-wind condition, the pilot can perform a ground-based constant radius turn by accurately maintaining a constant bank angle throughout the turn.
However, with any wind the complexities of maintaining a ground-based constant radius turn increase.
When wind is present, during ground reference maneuvers involving turns, the pilot must correct for wind drift.
Rectangular Course (AFH C6)
A principle ground reference maneuver is the rectangular course.
The rectangular course is a training maneuver in which the airplane maintains an equal distance from all sides of the selected rectangular references.
The maneuver is accomplished to replicate the airport traffic pattern that an airplane typically maneuvers while landing.
Turns Around a Point (AFH C6)
The maneuver is a 360° constant radius turn around a single groundbased reference point.
The principles are the same in any turning ground reference maneuver:
Higher groundspeeds require steeper banks
Slower ground speeds require shallower banks.
S-Turns (AFH C6)
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.
Failure to adequately clear the area above, below, and on either side of the airplane for safety hazards, initially and throughout the maneuver.
Failure to establish a constant, level altitude prior to entering the maneuver.
Failure to maintain altitude during the maneuver.
Failure to properly assess wind direction.
Failure to properly execute constant radius turns.
Failure to manipulate the flight controls in a smooth and continuous manner when transitioning into turns.
Failure to establish the appropriate wind correction angle.
Failure to apply coordinated aileron and rudder pressure, resulting in slips or skids.
Private Pilot ACS Standards
Clear the area.
Select a suitable ground reference area, line, or point as appropriate.
Plan the maneuver: Note: The evaluator must select at least one maneuver for the applicant to demonstrate.
Rectangular course: enter a left or right pattern, 600 to 1,000 feet above ground level (AGL) at an appropriate distance from the selected reference area, 45° to the downwind leg
S-turns: enter perpendicular to the selected reference line, 600 to 1,000 feet AGL at an appropriate distance from the selected reference area
Turns around a point: enter at an appropriate distance from the reference point, 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.
If performing S-Turns, 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.
FAA Sources Used for This Lesson
Private Pilot Airmen Certification Standards
Airplane Flying Handbook (AFH) Chapter 6