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Gliding a skill that should be practiced

 

When an engine fails in a single engine airplane, it becomes a glider and often not a very good one.

You must get the aircraft nose down quickly to get your glide speed. In some aircraft and ultralights, that may mean a very significant and rapid pitch change. It is a good idea to know what the power off rate of descent is in your aircraft and how to determine the point of zero movement on the ground as quickly as possible.

The speed for the maximum glide range is published in the Aircraft Flight Manual and is the power off airspeed that will give an aircraft its longest gliding distance. It is the average airspeed for the best lift/drag ratio for the aircraft.

Flying at an airspeed higher or lower than the recommended glide speed will reduce the gliding distance. A higher airspeed will require a lower pitch attitude (angle of attack) and an increased rate of descent. A lower airspeed will require a higher pitch attitude (angle of attack) resulting in increased induced drag, which will increase the rate of descent.

Maximum glide range is affected by the aircraft weight. The heavier the aircraft the less distance it will glide when the recommended glide speed is flown. A heavier aircraft will actually glide a little farther at a slightly higher airspeed, but you usually will not know what that airspeed is.

Maximum glide range is adversely affected by drag. Keep the gear and flaps up.

Wind affects the maximum glide range. You may be able to increase your glide range by adding a few knots to the recommended glide speed in a headwind, or by decreasing a few knots in a tailwind. The increase will be small and likely not worth it unless you are gliding from a very high altitude.

In an emergency, fly the recommended glide speed and concentrate on the procedure for the forced approach.

The propeller affects the glide. A windmilling propeller at fine pitch will seriously decrease the glide range. A windmilling propeller at course pitch will also decrease the glide range, but not by as much. A stopped propeller will reduce the glide range less yet, and a feathered propeller will reduce it the least.

Stopping a fixed pitch propeller may be possible if you reduce the airspeed to just above the full flap stall. This procedure may cause as much altitude loss or more than the windmilling propeller.

Point of Zero Movement

In a glide, the point of zero movement is the point on the ground that you can see that is not moving. All ground features above the point of zero movement appear to be getting farther away. They are moving up in the windscreen. All ground features below the point of zero movement appear to be getting closer. They are moving down on the windscreen.

Engine Failure after Take-off

Do not try to turn back to the runway below at least 800 feet on a straight out departure. Your chances of making it are slim to none. Below 800 feet on a straight out departure, pick a place to “land” within 30 degrees of your heading, perform a cause check if there is time, call MAYDAY and secure the engine. Do not let checks distract you from performing the best forced approach you can.

If the engine fails after a crosswind turn has been made, you will be above 500 feet and will have about 120 degrees to turn. It may now be possible to glide to the runway, or at least to the infield.

Engine Failure at Altitude

There are at least three ways to perform a forced approach. Use whatever works to get you onto a final approach to the selected landing area.

Once you have turned to final, pick the touch down point and aim for it. If the airspeed starts to decrease, you know immediately you cannot make the landing site, and you may have a little time to choose an alternate site.

If the airspeed starts to increase, use flaps to reduce the airspeed, or a slip to reduce altitude more quickly. Even if you just dive for the landing point, you will make the field. You may not be able to stop before going into the trees at the end of the field, but you will do so at a lot slower speed than you would if you overshot the field and flew into them.

If you find yourself much too high on final, slip away from the landing site rather than toward it. The slip away will increase your distance from the site at the same time as increasing your rate of descent. The effect of the slip is increased significantly.

If you are flying a retractable aircraft, the general rule is lower the landing gear for a rough field. The landing gear will take a lot of the shock of the rough surface before being sheared off. If the surface appears to be very soft, leave the landing gear up to avoid flipping over or cartwheeling.

Landing into the trees

If you are flying over remote areas, this is something you must think about.

Fly the glide speed right into the trees. The trees will slow the aircraft rapidly to a speed well below the stall speed. Do not stall the aircraft above the trees as your velocity at ground contact will likely be considerably higher than it would be if you maintained the glide speed, and the chance of injury will be greater as well.

Gliding should be practiced periodically to remind you of how far the aircraft will glide and how the aircraft handles at glide speed without power. The more proficient you are as a glider pilot, the more successful you will be when you suddenly become one.