Instrumentation

Characteristics and General Definitions
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Figure 1.6 A three pointer airspeed
indicator
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2
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A further solution, shown in Figure 1.6, is to display information
in a similar fashion to a clock, with pointers showing hours,
minutes and seconds. This system is used on many altimeters.
The long pointer will cover 1000 feet in one revolution, so each
division of the scale represents 100 feet. The middle pointer
will cover 10 000 feet per revolution, each division marking
1000 feet and the smallest pointer will cover 100 000 feet, each
division representing 10 000 feet.
Figure 1.6 indicates a height of 25 950 ft.
Characteristics and General Definitions 1
Ergonomy
Ergonomy (also known as human engineering) is the science of relationships between people
and machines. An ergonomic device interacts smoothly with peoples’ bodies and actions. In
an aviation context this can mean designing the shape and position of controls, levers and
knobs so that they are easily controlled and unlikely to lead to an incorrect selection. For
instruments or instrument systems it means designing instruments that are unlikely to be
misread and locating them in a layout that facilitates easy and correct interpretation of the
information displayed. Standard layouts came to be adopted.
Location
The ‘flying’ instruments which covered the handling of the aircraft were arranged in the layout
of the ‘basic six’. Other instruments tended to be scattered around the cockpit in positions
most convenient to the designer and manufacturer, seldom to suit the needs of the pilot.
AIRSPEED
INDICATOR
GYRO
HORIZON
ALTIMETER
TURN
&
SLIP
COURSE
INDICATOR
VERTICAL
SPEED
Figure 1.7 The ‘basic six’ instrument layout
Since the introduction of the ‘basic six’ developments in aircraft instruments and operations led to the
introduction of the ‘basic T’.
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