Cessna 208B - Enginemount; Propeller Overspeed Governor

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SECTION 7 CESSNA -.
AIRPLANE AND SYSTEMS DESCRIPTION
MODEL
2088 (675 SHP)
ENGINE ACCESSORIES (Continued)
PROPELLER OVERSPEED GOVERNOR
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This propeller overspeed governor is located at the 10 o'clock position
on the front case of the reduction gearbox. The governor acts as a
safeguard against propeller overspeed should the primary propeller
governor fail. The propeller overspeed governor regulates the flow of oil
to the propeller pitch-change mechanism by means of a flyweight and
speeder spring arrangement similar to the primary propeller governor.
Because it has no mechanical controls, the overspeed governor is
equipped with a test solenoid that resets the governor below its normal
overspeed setting for ground test. The overspeed governor test switch
is located on the left side of the instrument panel. For a discussion of
this switch, refer to the paragraph titled Propellers in this section.
ENGINE MOUNT
The engine mount is a 9-element space frame weldment fabricated
from 4130 steel. The space frame attaches to the
firewall at five points
and has an engine mounting ring that attaches to the front of the frame
at four points. The
forward mounting ring also facilitates engine removal
without disturbing the nose gear attachment.
ENGINE FlRE DETECTION SYSTEM
The engine fire detection system consists of a heat sensor in the
engine compartment, a warning light, labeled ENGINE FIRE, on the
annunciator panel, and a warning horn above the pilot. The heat sensor
consists of three flexible closed loops. When high engine compartment
temperatures are experienced, the heat causes a change in resistance
in the closed loops. This change in resistance is sensed by a control
box, located on the aft side of the firewall, which will illuminate the
annunciator light and trigger the audible warning horn. Fire warning is
initiated when temperatures in the engine compartment exceed 425°F
(218°C) on the first section (firewall), 625°F (329°C) on the second
section (around the exhaust), or 450°F (232°C) on the third section
(rear engine compartment). A test switch, labeled FlRE DETECT TEST,
is located adjacent to the annunciator panel. When depressed, the
ENGINE FlRE annunciator will illuminate and the warning horn will
sound indicating that the fire warning circuitry is operational. The
system is protected by a "pull-OW' type circuit breaker, labeled FlRE
DET, on the left sidewall switch and circuit breaker panel.
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