Exercise 20 – Illusions Created by Drift

The illusions created by drift lesson is often omitted in flight training as some instructors think it is boring, they are unsure of how to teach it or they think it is a waste of time. Exercise 20 is a lesson on human factors and is very important to all pilots including instructors. This flight is to increase the student’s ability to fly coordinated in challenging conditions and allows them to experience illusions in a safe environment. The general tone of the lesson should be as various exercises to see what the airplane does, how we as pilots perceive the aircraft’s behaviour and how to properly manage it.

Often times, instructors themselves have not had proper training in this lesson when they completed their PPLs. If this is the case, please read on and discuss this lesson with a Class 1 Instructor or a CFI.

Consider doing this exercise at 500′ AGL where applicable and safe. Make sure the student is coordinated the whole time.

 Initial Preparation

  • Find a suitable area to complete this exercise (if possible beforehand)
  • Configure the aircraft with normal approach flap and airspeed
  • Demonstrate how to determine wind direction by flying along a long road
  • Review how to crab

Speed Illusions

  • Align the aircraft into wind and along a road
  • While maintaining a constant airspeed and altitude, time the distance between two points (roads, towers etc,)
  • Point out reduced groundspeed
  • Fly in the opposite direction back down the same road timing between the same two points
  • Maintain same altitude and airspeed
  • Demonstrate increased groundspeed and reduced time

Student Practice

Turning Illusions

  • While at low altitude, turn the airplane into wind and show skidding illusions
  • Point out Turn Coordinator and point out illusion outside (TRUST TC)
  • Turn from headwind to downwind and show slipping illusion
  • Point out TC and illusion as seen outside

Student Practice

Flying Circles Around a Point

  • Find a suitable landmark you can fly around at 500′ AGL
  • Fly a perfect 360 degree circle around the landmark maintaining a uniform distance from it
  • Demonstrate how to adjust bank angle to maintain a perfect circle

Student Practice


S Turns

  • Complete S Turns along a road or powerlines with a crosswind
  • Vary bank angle to obtain a good radius turn each time
  • If using powerlines, a good game to play is to be perpendicular when crossing powerlines at every 4th or 5th tower (as applicable)

Student Practice

All of this information on pilot training and flight training in Canada is also available at www.myflighttraining.ca.