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Descending The correct method is to use PAT Power Attitude trim again. If you were above 3000ft and had leaned the fuel mixture and tuned the propeller, then the mixture lever & propeller lever should be pushed in fully at this stage. In the descent you will need to apply back pressure on the stick. This is to avoid the nose dropping too far and retrim. Keep the ball dead centre on the turn and balance indicator (using the rudder pedals). Watch your heading and attitude indicator to keep the wings level. Before descending have a good look below you for other aircraft. Descend doing an S type maneuver in uncontrolled airspace. This avoids you dropping directly on top of another aircraft. There is a blind spot directly below you and directly above a pilot in an aircraft underneath you. A similar thing should be done in the climb. In Controlled Airspace the Air Traffic Controller will have checked this and you would descend on the instrument procedure or the heading the controller told you.
After reducing power, hold your height until your airspeed drops back to the required descent speed. Do this by pulling gently back on the joystick, then gently lower the nose into the descent once the required speed is reached. A good control of pitch and power will achieve the correct descent speed. Target speed is 70 knots for a light aircraft. Just like the aircraft has a best climb speed it also has a best glide speed. In a long descent, power should be applied every 1000ft for a few seconds to warm the engine. If the engine has a carburetor then the carburetor heat switch must be pulled out for a few seconds. Ice can form in the engine causing an engine failure. Using the 10% rule, start to apply power so that the aircraft levels out without going under the required height. Before the descent ensure the altimeter is correctly set to the QNH or Flight Level setting. An incorrect altimeter setting is dangerous as for each millibar not set means the altimeter over reads by 30ft (remember this from the Altimeter lecture.) If you were going to enter an airfield circuit remember to set QFE not QNH. or in flight simulator add 1000 ft to the airfield elevation. IE Biggin Hill is 600 ft airfield elevation. Your circuit height is therefor 1600 ft after pressing the B key which sets the QNH. To get QFE it would be QNH-20 millibars. To Recap then to Descend Look below you. Propeller and fuel mixture lever fully in. Throttle lever fully out Apply back pressure on the joystick until the airspeed drops back to 70 knots then gently push the joystick forward and trim. Descend at 70 knots. In long descents warm the engine and make S turns. keep a good look out for other aircraft. To come out of the descent, apply power then get the attitude correct, then trim. For most light aircraft the best descent speed is 70 knots. Most light aircraft have a glide ratio of about 3 to 1. So for every thousand feet the aircraft loses it will glide three miles. If you speed is too fast pull back on the stick if too slow push it forward and retrim. You can now practice Climb, Level flight at different speeds, Descent and Level off. You will shortly be able to practice all you have learnt in the circuit. The next lesson is turning. |