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Emergency reduction of aircraft

# Emergency reduction of aircraft. Emergency landing.

The pilot must perform reduction with maximum speed and with the greatest possible angle of trajectory.

Flight speed Emergency lowering is limited to first speed corresponding to the maximum permissible number of M, and then the maximum velocity head.

From the equation that determines the angle of the trajectory of the steady decline can be seen that the angle of inclination of the trajectory will be greater, the more resistance and less traction power plants. Consequently, the pilot has a resistance of an aircraft engine operation as soon as possible to reduce and enlarge, acting in accordance with the flight manual (landing gear, spoilers deflection, etc..).

It should be borne in mind that the aircraft landing gear resistance increases very significantly (40-f-50%). So pa the aircraft, where the design features allow the landing gear in a relatively quick time, the possibility of increasing the resistance, it is desirable to use. At turboprop power plants operating in emergency mode reducing on earth idle, creating additional resistance (negative traction), which is added to the resistance of the aircraft and can increase the angle of descent.

Start an emergency reduction should be smooth, with a slight overload. Monitoring the input mode should be made by variometer. A further reduction is controlled by the sign of M and airspeed pointer.

Backlash roll.

Above it was stated that the aircraft roll bar tends to tilt in the opposite slip. This is the main reason for the aircraft kreneniya s side pedal rejected. Such a reaction is called a normal aircraft, or direct reaction of the aircraft in roll.

In flights with large M numbers, the airplane may approach the zone of noticeable changes in the cy coefficient from the M number (see 8). The "dip" on the curve of cv versus M number shifts in M ​​number depending on the wing sweep. The less the sweep, the earlier the “failure” begins and the more pronounced it is. If, in flight with the number M, at which the indicated phenomenon begins, the rudder pedal is deflected, then the half of the wing opposite to the deflected pedal, due to the resulting slip, will have, as it were, less sweep than the other half. A decrease in sweep will cause a decrease in the coefficient su and, as a consequence, a decrease in lift on the half of the wing opposite to the deflected pedal, and the aircraft tilting towards the sliding side, i.e., in the direction opposite to the deflected pedal. This phenomenon is called roll feedback. It can be encountered on a number of swept-wing civil aircraft when performing an emergency descent. Feedback on crepe is not particularly dangerous, but requires increased attention of the pilot.

Approach with icy stabilizer. In the planning of pre-lift of the stabilizer is directed downward. Formed at the same time the center of gravity itselfsummer dive counterbalances the moment the wing.

The magnitude of horizontal tail lift force depends on the speed and flight angle of attack, defined as ystanovochny angle stabilizer typically-2-4y. Bevel angle of flow is highly dependent on the position of lift devices (increases with the angle of the flap) and the mode of engine operation. On turboprop engines increase in operating mode causes a significant increase in the flow of the wing slant (up to 5-7 °, and more).

The angle of attack of the wing aircraft with full flap small. All this leads to the conclusion that the angle of attack of the horizontal tail on preplant mode has a large negative value (up -8n-10 ° or more).

In the absence of the icing on the angle of attack of the horizontal tail, and even when they are increasing due to the evolutions of the aircraft (speed, reducing congestion, and others.) Wrap stabilizer occurs normally and no special effects are not observed.

In the case of the appearance on the nose of the stabilizer of ice (which is possible under particularly severe icing conditions or in the event of anti-icing system) when a large negative angle of attack of the horizontal tail

born stall. In the initial stage of development failure is a redistribution of aerodynamic vacuum, causing an increase in the load on the elevator, tending to dismiss the wheel down. Pressures on the steering wheel at the same time are very great, and the pilot can not hold the steering wheel in the balancing position. In this case, there is a significant negative overload, and the so-called "peck" aircraft. With further development of the total breakdown occurs decreased lift of the stabilizer and, consequently, the transition plane in a steep dive.

Flight manuals for all types of aircraft provide for a landing approach with reduced flap deflection angles in the case of ice on the stabilizer. Compliance with this requirement, as well as the maintenance of the established flight speeds, engine operation mode and other indications, guarantees from entering the mode, at which the flow on horizontal plumage is possible. In the presence of ice unacceptably sharp piloting. Do not perform actions that lead to a significant increase in absolute value (for example, the release of flaps with a simultaneous increase in the mode of operation of the engines, the release of flaps with the release of the steering wheel from themselves, etc.).

In the event of pre-planning to in icing conditions pulling effort on the steering wheel and the desire to lower the plane's nose should make every effort to withstand the initial regime and at the same time remove the flaps.

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16.05.2021

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