Airplane
Clock
A clock is generally taken to mean a device to show
the time of day or night. However, a clocking device
may be any instrument that registers a given condition
such as the temperature of a place or clocking the revolutions
per minute of a machine.
The usual form of a clock is a round gauge, with one
or more needle indicators. The idea of a round gage is
useful because many people can tell with experience the
reading of the gauge just by looking at the positions
of the needles on the gauge. A slight glance will do.
People still prefer analog speedometer in their cars.
The needles of such instruments make a kind of sign during
operation, allowing the user to recognize at a glance,
from the motion of the needle as well as its angle, if
something is wrong with the system being monitored. Especially
with experience, the effort required to get an overall
picture from an analog gauge is usually less than that
needed to interpret and understand a digital readout.
Various Airplane Clocks
An airplane has a number of clocks, if they may be called
that. The Vertical Speed Indicator in an airplane shows
how fast the aircraft is climbing. The traditional form
of this instrument is a round gauge with a single needle.
Its zero position in the middle left. When the aircraft
is climbing, the needle moves clockwise, above the zero
point. In a dive, the needle rotates counterclockwise,
below the zero point.
An altimeter gauge shows the aircraft's height above
sea level. Multiple needles indicate altitude rather
like an analog clock indicates time the typical altimeter
greatly resembles a clock at first glance. An altimeter-style
gauge is very helpful in displaying a single quantity,
which must be monitored at several different scale levels.
A plane annunciator can be used to indicate
an emergency or error condition. Flashing lights alarms,
voice prompts and various combinations of the three can
be used to indicate such events. Annunciators are a very
useful source of supplemental information in a user interface.
Perhaps the most important form of a clock in an airplane
is the gyro. This constantly clocks the speed and the
direction of the aircraft very accurately.
There are many
more fixture articles in our fixture
section. There
is more specific information in the links at the beginning
of this article. They can guide you where you need
to go.
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