Fly By Wire System

AIRCRAFT FLIGHT CONTROL SYSTEMTypes of Flight Control linkagesMechanicalHydraulic-Mechanical (Power actuated System)FBW / DFBW

Mechanical ControlPush Pull Rod systemCable Pulley system

PUSH-PULL ROD SYSTEM3Components

TURN BUCKLESTORQUE TUBEBELL CRANCK LEVERFAIRLEADS

MECHNICAL FIGHT CONTROL SYSTEM

SERVO TABS

Power Actuated SystemWhen pilots action is not directly sufficient for actuating the control, power system is required to assist the pilot. HYDRAULIC SYSTEM has demonstrated more suitable solution for actuation, with respect to electric system.

OPERATION OF POWER ASSISTED CONTROL SYSTEMPilot send the signal (demand) to a valve that open ports through which high pressure fluid flows and operates the actuator.The valve , that is located near the actuator is signaled mechanically (Push-pull/Cable pulley). Two aspects must be notice when powered control is introduced:The system must control the surface in a proportional way.The pilot with little effort acts on a control valve must have a feedback on the maneuver intensity.

The above aspects are solved by using hydraulic servo- mechanics, where the components are linked in hydraulic circuit in such a way to introduce actuator stroke in proportional to pilots demand.Since pilot is no more aware of the loads imposed on the surfaces of the aircraft, an ARTIFICIAL FEEL SYSTEM is introduced acting directly on the cabin control stick or pedal.

Contd.

Disadvantages of Mechanical & Hydro-Mech SystemHeavy and require careful routing of flight control cables.Redundant backup will result in increase weight.Limited ability to compensate.FLY-BY-WIRE SYSTEM

IntroductionElectrically signaled control system.Computer configured controlModification in manual input of the pilot according to control parameters.This architecture is based on computer signal processing.

Operation Pilots demand is transduced into electrical signal and sent to a group of independent computers.The computers sample the data concerning the following :Flight conditions Servo valve positionActuator position

Then the pilots demand is processed and sent to the actuator. Flight Data

Redundancy of systemThe full system has high redundancy to restore the level of reliability of a mechanical or hydraulic system in the form of multiple(triplex or quadruplex ) parallel and independent lanes to generate and transmit the signals and independent computers to process them.

AdvantagesImproved flight SafetyReduced pilot workloadReduction of mechanical partsReal time monitoring of all aircraft system.Flight envelope protection Turbulent suppression and consequent decrease of fatigue loadsDrag reduction by an optimized trim settingBenefits for OperatorWeight Saving Lower Maintenance costGreater precision in flyingAircraft is kept within the flight protection envelope.Thus the pilot always can get the maximum performance out of the aircraft without running the risk of exceeding safety margins.The weight savings from the replacement of heavy mechanical control cables provides a significant reduction in fuel consumption. In additional, as electrical controls are less complex and easier to maintain than mechanical ones, the use of fly-by-wire translates into lower maintenance costs for operators. 19TodayFly-by-wire has now become the industry standard.large majority of pilots praising the handling qualitiesIt is installed, from the companys smallest aircraft the A318 to its double-deck A380 and new-generation A350 XWB.