Flying on the Boeing 777
Wednesday, 04 January 2006 02:01
Hi Capt Lim,
Wishing you a Happy New Year 2006!
I know it is really embarrassing for me to ask this, but can you please explain what exactly is the fly-by-wire system?
Thanks a lot.
Very simply, “wire” here means “electric or electronic signals”.
In the past, the flight controls of planes were connected to the pilots by cables ( just like those strings steering the rudder of a motor boat). For instance, on the old Boeing 707, when the captain wished to climb, he pulled the flight control wheel up (needed quite a bit of force). This in turn moved the elevator. That movement was possible because of cables that can be hundreds of feet long. Yes, these cumbersome, lengthy and heavy cables are now replaced by electronics or electrical wires. Hence, the term “fly-by-wire” (FBW)
Today, when I wish to perform a climb on the Boeing 777, I merely pull back the control wheel gently, the signal is transmitted instantaneously to the elevatiors near the tail. Well, there are no cables running up from the cockpit to the back (about 209 feet long) to perform this climbing action.
Welcome to the world of electronics! Ah…really, there is nothing to shout about! FBW technology was introduced in the military aviation in the 1940s and the Concorde was the first fly-by-wire airliner. This technology was slow to be introduced widely into the commecial airlines until the Airbus A320 took the lead in 1984. Since then, all the subsequent Airbuses are designed with FBW technology whereas Boeing only began to work on this in 1994 on the 777s.
Flying by wires means that there are no direct mechanical links, cable or hydraulics, between the pilots and the control surfaces. This eliminates weight and reduces complexity in removing cables, linkages and hydraulic tubing. It also facilitates the use of software to be incorporated into the autopilot system for safer flying.
I have also answered questions relating to FBW in the following:
1. How does the fly-by-wire in Boeing 777 differ from the Airbus system? (Link broken)
2. How effective is the mechanical back up on the Boeing 777 fly-by-wire system? (Link broken)
3. What is the effect of electrical failure on a fly-by-wire aircraft? (Link broken)
The Airbus A320 Fly-By-Wire Demo