二号图书馆各种英文版手册.pdfVIP

DESCRIPTION Nosewheel steering is provided by two actuators, powered by the green hydraulic system and electrically-signaled by the Brake and Steering Control Unit (BSCU). The yellow hydraulic system is used as a backup, to power nosewheel steering when the green hydraulic system is unavailable. The BSCU has two t systems. Only one is active at a time, while the other is on standby. To control the steering, the BSCU receives inputs from the steering handwheels, the rudder pedals, the rudder trim, and the Auto Pilot. The BSCU transforms the pilots order into a nosewheel steering angle, by controlling the servovalve to provide the requested flow for the hydraulic actuators. The following limitations apply : The steering handwheels control the nosewheel steering angle up to 75 in either direction. A lever on the towing electrical box (on the nose L/G) enables the steering system to be deactivated for towing purposes. Pilots can disconnect the rudder pedal order to the BSCU via a pushbutton located on each steering handwheel. An internal cam mechanism returns the nosewheel to the centered position after takeoff. CONTROLS AND INDICATORS RUDDER PEDALS Nosewheel steering control authority depends on aircraft speed. Rudder pedals provide nosewheel steering control : – Below 100 knots at landing – Up to 150 knots at takeoff. Outside the nosewheel steering control authority range, the steering demand remains at 0 . Note : The nosewheel steering angle depends on aircraft speed. SIDE CONSOLES STEERING HANDWHEELS The steering handwheels control the nosewheel steering angle up to 75 in either direction. RUDDER PEDAL DISC pushbutton When maintained pressed, nosewheel steering is disconnected from the rudder pedals. ECAM WHEEL PAGE N/W STRG indication In normal operation, nothing appears. N/W STRG label It