gyroscopic instrument family is
so named because the instruments are powered by gyroscopes. Gyroscopes
are very similar to the spinning tops you played with as a child. The
high rate of rotation of the spinning mass causes it to resist changes
in axis of motion. A gyroscope is placed inside each of the instruments,
and the airplane literally moves around the spinning gyro while the gyro
remains stationary. This allows the airplane to be bumped, change bank
or pitch, or go through turbulence without upsetting the correct information
displayed on these instruments.
turn to the right
indicator is the most important member of the gyroscopic instrument
family. It displays the attitude of the aircraft in relation to the earth’s
horizon, thus showing bank and pitch information. It is sometimes called
an artificial horizon. During your first few hours of flight training
you will learn to use the nose of the aircraft and its relationship to
the horizon to correctly enter and stay in turns, keep the aircraft straight
and level, and makes climbs and descents. During most flight you will
use these outside references, rather than internal instruments, to correctly
fly the aircraft. You will, however, learn to use the attitude indicator
and other instruments, to verify the precision of your flying. And when
you lose outside visual references due to clouds or reduced visibility,
you will learn to fly the airplane correctly with reference to internal
indicator is the chief direction instrument for the aircraft.
It is sometimes called the directional gyro, or DG. Due to the many errors
in the aircraft magnetic compass, the heading indicator’s use of
a gyroscope allows it to maintain directional accuracy over time.
have one major drawback: they exhibit a physical principle called precession.
It is impossible to completely maintain a gyroscope in a frictionless
environment. Whenever an airplane changes pitch or direction, friction
acts on the gyro by applying a force approximately 90 degrees ahead of
the direction of rotation. These forces are small, but still lead to minor
erroneous indications that increase over time.
Due to precession, it is important to recheck the
heading indicator against the magnetic compass every 15 minutes or so.
This should be rechecked only in straight and level flight.
turn and bank indicator is the third member of the gyroscope
family. It utilizes a gyroscope to indicate rate of turn and can also
be used as a secondary instrument to indicate bank. A turn
and slip indicator uses a needle to indicate full rate or half
rate turns, while the turn and bank or turn coordinator utilizes a miniature
airplane to indicate this information.
Placing the needle
or miniature airplane on the left or right marking will indicate a standard
rate turn. A standard rate turn is defined as a two-minute turn 360-degree
turn. In other words, for every minute, the aircraft will turn through
180 degrees, or half of a complete circle. A half standard rate turn only
turns through 180 degrees in two minutes.
Why is the rate
of turn information important? During your later instrument rating training,
air traffic control you expect you to complete most of your turning maneuvers
at standard rate.
is a non-gyroscopic indicator usually contained in the turn coordinator
or turn and slip indicator. The inclinometer is simply a ball contained
in colorless fluid similar to the leveling tools utilized by carpenters.
It allows you to make sure that the airplane’s vertical axis is
correctly aligned with the other axes of the aircraft. If the rudder is
not applied correctly in turns or other flight, the airplane can skid
or slip, placing the vertical axis out of alignment. By using the rudders
to center the ball on the inclinometer, coordinated flight is assured.
The inclinometer will help you gain a correct feel for the airplane as
you are learning to make smooth, coordinated maneuvers.