Section 7 Pilot’s Operating Handbook
Description of Airplane and Systems EXTRA 500
Special operation conditions:
All blade pitch angles except for the feather position require
servo oil pressure mainly to overcome the force provided by the
spring in the propeller hub. Therefore all operation conditions
leading to a loss of servo oil pressure will result in the propeller
to into the feather pitch angle position. This occurs in normal
operation in case of engine shutdown. Engine or system failures
leading to a loss of servo oil pressures also result in the prop to
go into the feather position resulting in minimized drag and
improved glide performance of the airplane in these emergency
conditions.
In case the prop governor should fail to maintain propeller
speed below operational limits (system failures) the additional
overspeed governor dumps servo oil pressure at 2210 rpm
(109%) and in addition reduces fuel supply to minimum flow at
2290 rpm (113%) to avoid an excessive overspeed condition.
For
operation in icing conditions, the propeller incorporates an
electrothermal de-icing device.
The system is controlled by the
PROP switch, located on the
DEICE panel. Continuous heat provided by the de-ice pads
reduces the adhesion between the ice and the propeller so that
centrifugal force and the blast of the airstream cause the ice to
be thrown off the propeller blades in small pieces.
Important Do not operate the propeller heat longer than ten (10)
seconds when engine is not running. The elements can
overheat and damage to the structure can occur.
7-40 26. January 2011
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