Learjet 60 - ENG FIRE PULL Light; Engine Fire Detection System; Engine Fire Extinguishing System; Fire Extinguishing System (Figure 2-4)

Leaqet6o
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Pilot's Manual
ENGINE
FIRE
DETECTION SYSTEM
Three heat-sensing
elements connected in series are
located in each
engine
nacelle to detect an engine fire . One
element is located around
the accessory gearbox ; one is located
around the engine tailcone ; and
another around the engine
firewall, On some aircraft, the fire detection
system is
controlled by two fire-detect control boxes located in the
tailcone
. On other air - craft, the fire detection system is
controlled by a
single fire-detect control box located in the tailcone . In
the event of an
engine fire, the control boxes) will sense
a resistance change in the
sensing elements and
flash the applicable ENG FIRE PULL light .
Electrical
power for the system is 28 VDC supplied through
the 7 .5-
amp L and R FIRE DETECT circuit breakers on the
pilot's and copilot's
circuit breaker panels respectively . The
fire detect system is operative
during EMER
BUS mode
.
SYSTEM TEST SWITCH - FIRE DETECTION
FUNCTION
The
rotary-type SYSTEM TEST switch on the instrument panel is used
to test
the fire detection system . Rotating the switch
to FIRE DET and
depressing the switch TEST button
will connect a resistance into both
fire detect system circuits .
This resistance, simulating an engine fire,
will cause
both ENG ERE PULL lights to
illuminate
and
flash . It also
,ts and lights the ENG EXT ARMED
lights . This test function also
tests the taikone bleed
air
overheat
system . Depressing the TEST
but-
ton will cause both red
BLEED AIR L and BLEED AIR R lights
to illu-
minate, These
tests check the heat-sensing elements for
continuity .
ENG FIRE PULL LIGHT
ENO FIRE PULL
warning light is installed on the glareshield to
the crew of a fire in the associated engine nacelle .
In the event of
an
engine
fin, the associated ENG FIRE PULL
light will illuminate and
flash . The light is part of a T- handle
. Operation of the T-handle is ex-
plained under ENGINE FIRE
EXTINGUISHING SYSTEM .
ENGINE
FIRE EXTINGUISHING SYSTEM
The engine fire extinguishing system components include : two spheri-
cal extinguishing agent containers, an ENG FIRE PULL
T handle for
each engine, two amber ENG EXT ARMED
light/switches, a hydraulic
shutoff valve for each engine, a
fuel shutoff valve for each engine, a
thermal discharge indicator, a
manual discharge indicator, and associ-
ated wiring
and plumbing . The system also utilizes the pneumatic sys-
tem bleed-air shutoff valves . The system is
plumbed to provide the
PM-In
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