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HOAC AUSTRIA
DV 20 Flight Manual
Description
Instru
me
nts
The instruments for temperatures, oil pressure, and fuel quantity are connected in series with the
respective sensors. The electrical resistance of a sensor changes with the measurable variable,
which causes the power to the instrument and consequently the needle deflection to change. Oil
pressure indicator, cylinder head temperature indicator and fuel pressure waming light are supplied
with power through one circuit breaker. Oil temperature indicator and fuel quantity indicator are also
protected together by one circuit breaker.
7.12. PITOT AND STATIC PRESSURE SYSTEMS
The total head is measured on the leading edge of a calibrated probe below the left wing. The static
pressure is measured by the same probe using two holes in the lower edge and rear edge of the
probe. For protection against dirt and humidity, filters are installed in the line. These filters are
accessible beneath the left seat.
The error of the static pressure system is small enough to be neglected for the measuring of the
altitude. For the error of the airspeed indicating system refer to Chapter 5.
7.1 3. STALL WARNING SYSTEM
When the airspeed drops below 1 . 1 times the stall speed, a horn sounds in the left instrument panel.
The horn grows louder as the speed approaches the stall speed. The horn is activated by suction on a
hose that leads from a hole in the leading edge of the left wing to the horn. The hole is marked by a
red circle around.
7.14. AVIONICS
The center of the instrument panel contains the radio and navigation equipment. The microphone key
for the radio is installed in the control stick. There are two connectors for headsets on the backrest of
the seat.
Operating instructions for individual avionics equipment should be taken from the manuals of the
respective manufacturers.
ReviSion No.
Reference
Date
October 20, 1 993
Page
7
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1 6