Page 128 - Understanding Flight

CH04_Anderson 7/25/01 8:57 AM Page 115

Stability and Control 115

the pilots the same feel as the old mechanical linkages. Of course,
now this means that the stick force and balance can be tuned with
software. But, at the same time, this is extra hardware, and thus
weight, which only serves the purpose of making the pilot more
comfortable. However, safety in itself provides a justifiable argument
in favor of such systems.
The computer has resulted in an interesting aspect of handling
properties. With the computer installed between the pilot and the
control surfaces the properties of stick force and balance can be
changed in software. This can be useful in a new airplane
development program. For example, the expected handling
properties of the Boeing 777 were programmed into a Boeing
On June 10, 1965, the first fully
757, which was flown extensively by the test pilots before the
automatic landing of an in-service
first Boeing 777 was even built. The first flight of the Boeing
commercial airplane occurred at
777 went off without a hitch, in part because the pilot had
London, Heathrow airport.
many simulated hours flying a Boeing 777.

Wrapping It Up

In this chapter you were introduced to basic concepts of stability and
control. There is a great deal more detail that could be covered on this
topic, but you have been given a basic introduction as a starting
point.
In the early days, stability and control were not as significant a part
of the airplane’s design as they are today. On a modern airplane,
commercial and military, the stability and control systems include
computers. The computer has many capabilities, and engineers are
learning more ways to use them. So, in addition to augmenting
stability, an airplane’s computer may take navigation data, instrument
landing data, air traffic data, and weather data and create and execute
a flight path. In fact, the computer alone can fly an entire
flight, from takeoff to landing. The pilot’s job becomes more
The cost of modern airplane
of a systems monitor than the person flying an airplane. There
computer and electronics systems
is a joke that a pilot and a dog will fly the airplanes of
is approaching 50 percent of the
tomorrow. The dog’s job will be to bite the pilot’s hand if he
cost of the airplane.
touches the controls and the pilot’s job will be to feed the dog.