European Stars And Stripes (Newspaper) - July 17, 1988, Darmstadt, Hesse                                Cockpit of the a320 Airbus. The traditional column control is replaced by the Side stick. By Barnaby. Feder new York times shortly after the crash of the Airbus a320 at a French airshow at Mulhouse late in june the French pilots Union attributed the Accident to the plane s innovative Fly by wire control system. The a320, built by the european consortium Airbus industries is the first aircraft designed for traditional commercial operations to rely mainly on electronic commands sent via electrical wiring to control the air plane. Traditionally pilots have used a Large wheel or control stick which the Pilot grasps like the steering wheel in an automobile to manipulate cables that physically Start and Stop such devices As motors and pumps. These devices move the mechanical systems that control flight the rudder for example or the flaps on the wings. By contrast the Pilot in an a320 flies the plane with a controller that resembles the Joystick for a computer game. It is known As a Side stick because it is mounted at the Pilot s Side where it will not interfere with the View of display panels. Movements of the stick Send electrical signals to computers that translate them into commands for the aircraft s moving parts. Aircraft engineers said the pilots Union will have a Tough time supporting its claims. The Airbus controls Are new to general commercial aviation but hardly a Blind leap into the technological unknown. They Are closely related to the controls widely used in military aircraft. Similar controls have also been used for 19 years on the concorde the Only commercial aircraft designed to Fly faster than the Speed of sound. And French government investigators said their initial conclusion was that none of the a320 s systems had malfunctioned. As a result the air plane builders expect development efforts to continue on control systems like the a320 s. Boeing co., for instance said it is leaning toward Fly by wire for its next air plane. And Mcdonnell Douglas corp., another . Company said it might favor Fly by wire if it were designing an air plane from scratch. Aircraft design engineers said that the All electric approach offers weight savings As Well As lower Assembly and maintenance costs. Fly by wire saves hundreds of pounds and is much easier to install when you Are building the plane said Peter Sutcliffe chief Engineer for advanced technology in Boeing s commercial aircraft division. Sutcliffe said that wiring could simply be Laid along a path while steel cabling had to be installed with close attention to details that affect its performance such As tension and alignment to the device being controlled. That process known As rigging has to be redone whenever parts must be removed in servicing a plane. The biggest advantage of Fly by wire is that the electrical network is ideally suited for the use of computers. Planes under computer control can respond More quickly to turbulence and other changes in flying conditions. Computers can also be programmed to see to it that a plane is never forced into a Man Euver it is not designed to handle such As a turn so Sharp that it would crack an aircraft s body. Such capabilities Are a major reason that aircraft manufacturers turned Long ago to Fly by wire technology to meet the exceptional demands placed on supersonic aircraft like the concorde and military planes. Despite the advantages of electronic controls commercial aircraft manufacturers and their customers have been moving cautiously toward Fly by wire technology. The control systems based on cables and Hydraulic lines Are tried and True descendants of the familiar controls used by the bicycle and automobile manufacturers who pioneered in aviation. Aircraft manufacturers noted that their customers primary concern is that travellers have absolute Confidence in the safety of the air plane s control system. Having established that Confidence with traditional control systems the airlines Are interested in the potential advantages of Fly by wire but Are in no mood to Rush toward it. Airlines for instance do not have the military s pressing need for High performance under extreme conditions and Are under less pressure to Cut weight. Nevertheless the commercial sector s transition is Well under Way. Airbus began in 1983 to use Fly by wire to control some of the flaps and spoilers that Man Euver its a310 and applied the technology the following year to parts of the a300-600. Boeing uses Fly by wire to communicate with the electronic controls of the Pratt & Whitney engines on its new 757s. More important perhaps the automatic Pilot system in such widely used aircraft As the Boeing 747, Mcdonnell Douglas corp s dc-10 and Lockheed corp s l-1011 tristan Are in essence skeletal Fly by wire systems that operate parallel to or As part of traditional Cable and Hydraulic systems. The new technology however requires extensive backup systems for the computers the software that runs them and the wiring itself. For example the electrical networks can be disrupted by an Accident or by radar lightning and other forms of intense Energy or magnetism. Replacing mechanical controls with computers air planes Are controlled by devices on the surface of the wings and the Tail. On the Wing ailerons control turning and banking while spoilers determine the rate of descent. Elevators on the Tail s horizontal surface determine the Angle of flight while the rudder on the Tail s vertical surface determines direction. In most civilian planes cables move these controls often in combination with Hydraulic systems. In a Fly by wire plane the movements of a Small control stick Are interpreted by computers which Send electrical signals to mechanical devices that move the controls. In the Airbus a320, two computers control the elevator and ailerons Elac three others control the spoilers and ailerons Sec. The computers Back each other up. The solid lines show the control for which each computer has prime responsibility. The lines of dashes show the Back up responsibilities. Sunday july 17, 1988 the stars and stripes not Page 17