AN-140 AIRCRAFT CONTROL SYSTEM

The system is designed for control of:

- ailerons; - rudder;
- elevator; - flaps;
- control locking; - actuator of rudder wheel column;
- trimming devices of rudder, of ailerons elevator; - disconnection of wiring.

The ailerons and elevator control are provided by hand from wheel columns or by commands of automatic flight control system. Rudder control - from individual pedals of pilot-in-command or co-pilot. Flaps control-from linear of flaps control, which may be used by captain or co-pilot.

Aileron control (non-boosted) is provided via mechanical linkage. Mechanical linkage is combined: in fuselage it is cable one, in wing - it is made with using rods. Geared trim tab is installed on every aileron.

Control of trim tab, installed on the right aileron is fly - by wire and it is ensured by pushing the switch aileron trim tab on the central panel.

The neutral position of trim tab is monitored by lighting of annunciator “neutral aileron trim tab”, located on the central panel.The annunciator “check aileron trim tab” lights on the upper control panel at deflected position of trim tab on the ground.

Disconnection the ailerons control wiring with switch “Boards disconnection of ailerons” on the central panel is provided.

Ailerons control in mode of automatic flight control panel is performed by means of autopilot servo unit, geared with starboard with mechanical linkage. Ailerons locking on the ground is fly-by-wire, from lever “gust locks on” on the left wall of the central control panel. Locked ailerons position warns annunciator “Fixed controls” on the lower panel of the upper control panel.

RUDDER CONTROL

Rudder control (non-boosted) is provided by using of spring trim tab of balance tab and pedals via mechanical linkage. Mechanical linkage is combined one; in fuselage is cable one in fin it is made with using rods. Trim tab control is fly-by wire at pushing of switch “Rudder trim tab” on the central panel. The neutral £ £ £ position of trim tab-balance tab is monitored by lighting of annunciator “neutral rudder trim” on the central panel. The annunciator “check rudder trim” will light on the lower panel of the upper control panel on the ground at deflected trim tab-balance tab.

The actuator, limiting the travel of trim-tab - balance tab and servicing the function of changes of gear ratio of rudder channel control is installed in control channel of rudder.

Actuator control, limiting the travel of trim tab - balance tab is fly-by-wire.

In automatic mode the control of actuator, limiting the travel of trim tab - balance tab (two-position switch “Reserve rudder control columns” set in position OFF) take places at installation of flaps in position d 3 £ 50. In standby mode (switch “Reserve rudder control columns” will set to position ON), the control of travel of trim tab - balance tab limiting travel is performed by deflection of pushing switch “Reserve rudder control column” to sides “Take off/POOS and cruise.

Rudder locking on ground is fly-by-wire, from lever “Gust locks” on the left wall of center panel. Rudder locked position is warned by annunciator “Gust locks OFF” on the lower panel of the upper control panel.

Elevator control (non-boosted) is provided by control columns via mechanical linkage. Mechanical linkage is combined: in fuselage - a cable linkage, in vertical stabilizer it is mode with using rods “Each section of elevator is equipped with trim tab and trim-tab - balance tab. The trim tabs of both sections of elevator are deflected by unique transmission driven by two electric actuators (consecutively installed) of trimming (main and standby). Each trim tab - balance tab, except the geared linkage with own elevator section, can be displaced with individual electric actuator of trimming.

Elevator trim tab control is fly-by-wire. In main mode (from buttons “dive - pitching up” on the left and right control columns) the trimming is performed by pulse switching the main electric actuator of trimming.

The first standby mode of elevator trimming (from press switch “1 Reserve elevator trim” on the central panel) is used to switch the standby electric actuator of trimming while pressing switch button.

The second standby mode of elevator trimming (from double press switch “2 reserve elevator trim” on the central control panel) is used for switching trimming electric actuator of trim-tab balance tabs at pressing the switches button.

The trim tab - balance tab electric actuator activation is monitored by light of annunciator “Left is not neutral” or “Right is not neutral” on the central control panel.

Annunciator “No neutral” on the center control panel and “Check elevator trim” on the upper control panel is monitored by activation of trim tab electric actuators and trim tabs-trim-balances.

Disconnection the boards of mechanical linkage of elevator control by means of switch “Boards disconnection elevator” on the central control panel is provided. Control of actuator for boards wiring disconnection is fly-by-wire, there is an annunciator “Boards disconnection elevator” on the upper control panel. Connection of boards wiring is ensured only on the ground by means of control panel of elevator control wiring connection installed on starboard, on frame No. 38.

Elevator control in mode of automatic flight control is performed by means of autopilot servo unit, geared by mechanical linkage with portside. The manual trimming is locked at switching of automatic flight control.

The elevator locking on the ground is provided only by elevator deflected down. Locking control is fly-by-wire, from lever “Gust locks on” on the left wall of the central control panel. The elevator locking position is signaled by lighting of annunciator “Gust locks OFF” on the upper control panel.The flaps control system provides synchro, fly-by-wire control of symmetrical pair of flaps sections, connected to rotating cardan shafts with power drive KPM-02. The retraction preventive brakes PUT and transmitters of flaps position asymmetry (BR-48 units) are installed on the transmission ends. The power drive KPM-02 is combined, it includes the hydraulic motor and DC current electric motor. Two modes of system operation in flight (main and standby) are provided.

In main (tracking) mode of system operation the hydraulic motor of drive KPM-02 and PUT are monitored by control monitor BUK3-400, connected to transmitters of Flaps control lever position on the central control panel.

Position of flaps is monitored by indicators UPZ-72PP on the middle panel of instrument panel. At flaps asymmetry more than allowable, the automatic stop of drive and transmission fixation by means of PUT takes place and annunciators “flaps-asymmetry”, “Flaps-main control failure” on the lower panel of the upper control panel light. At this it is not allowable the continuation of extension and retraction of flaps in any mode. If the flaps were not installed on the ground in take-off position then at declination of engine control lever to position corresponding to mode of the most maximum continuous, the annunciators “Check flaps” on the lower panel of the upper control panel and “Take off is not allowed” on the left and right panels of instrument panel will right.

In standby mode of the discrete extension (retraction) of flaps from press switches on control panel of “Reserve, flaps”, controlled by work of drive electric motor KPM-2, is performed.

 


IRAN-140 PROJECT

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