Propeller Overspeed Governor; Engine Fire Detection System - Textron Cessna Grand Caravan Ex 208B Pilot's Operating Handbook And Faa Approved Airplane Flight Manual

SECTION 7 CESSNA
AIRPLANE AND SYSTEMS DESCRIPTION MODEL 208B 867 SHP
GARMIN G1000

PROPELLER OVERSPEED GOVERNOR

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
PUSH TO 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 FIRE DETECTION SYSTEM

The engine fire detection system consists of a heat sensor in the
engine compartment, a red ENGINE FIRE annunciator located on the
PFD, 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 red
ENGINE FIRE annunciator and trigger the audible warning horn. Fire
warning is initiated when temperatures in the engine compartment
exceed 425ºF (218ºC) on the first section (firewall), 625ºF (329ºC) on
the second section (around the exhaust), or 450ºF (232ºC) on the third
section (rear engine compartment).
A test switch, labeled TEST SWITCH, FIRE DETECT - UP, is located
on the lower left corner of the instrument panel. When this switch is
placed in the UP position, the red ENGINE FIRE annunciator will
illuminate on the CAS system and the warning horn will sound
indicating that the fire warning circuitry is operational. The system is
protected by a pull-off type circuit breaker, labeled FIRE DET, on the left
sidewall switch and circuit breaker panel.
7-72 208BPHCUS-00
U.S.