When student pilots begin to learn about emergency procedures, the concept of the engine-out glide is introduced. The CFI will usually discuss the procedures to be used when an engine failure has occurred. Typically the discussion goes like this:
- When the engine fails, the first step is to establish the aircraft at the airspeed for best glide.
- This best glide airspeed allows the aircraft to fly at it maximum L/D ratio, which allows the aircraft to glide the farthest horizontal distance for the least loss in altitude.
- The best glide airspeed is given in the POH in the section entitled “Emergency Procedures”.
- The airspeed that is shown is for the aircraft being loaded to gross weight.
- A rule of thumb to obtain the best glide speed at any aircraft weight is to
reduce the best glide airspeed at gross weight by one-half the percent reduction in gross weight. Thus, if the aircraft is loaded to 10% below gross weight, you should reduce the best glide speed at gross weight by 5%.
After this discussion with the student, the lesson proceeds with a flight that involves reducing the power to idle and pitching the aircraft to obtain the desired glide airspeed for the weight of the aircraft. The student responds to the simulated engine-out procedure by watching the airspeed indicator and pitches the aircraft to establish the airspeed at the target best glide speed and then trims the aircraft to that speed.