FIRE PROTECTION
SCOPE
General
Engine Fire Detection System
APU Fire Detection System
Engine/APU Fire Warning System
Fire Extinguishing System
FIRE PROTECTION
GENERAL
Fire protection for the 560XL aircraft consists of a detection
system and extinguishing system.
Provisions for fire detection are installed in the left and
right engine compartments and consists of a closed-loop
sensing system and detector control unit.
FIRE PROTECTION
GENERAL
Control unit which illuminates the respective red ENG FIRE
warning light on the cockpit glare shield if a fire or overheat
condition is present.
The light, under a transparent, spring-loaded guard, also
serves as firewall shutoff switch.
FIRE PROTECTION
GENERAL
Fire extinguishing system provided for the engine compartments is actuated by
lifting the guard and depressing the ENG FIRE warning light.
FIRE PROTECTION
GENERAL
Firewall shutoff and extinguisher arming are indicated by illumination of the
respective FUEL LOW PRESS, HYD FLOW LOW, F/W SHUTOFF.
It also illuminates GEN OFF annunciator panel lights and both white BOTTLE
ARMED lights.
FIRE PROTECTION
GENERAL
Once armed, either bottle may be discharged to the selected engine by pushing
the BOTTLE ARMED light.
The light will go out as it is pushed.
System plumbing is such that both bottles can be directed to the same engine
if necessary.
FIRE PROTECTION
DETECTION
GENERAL
This section provides maintenance information on the fire detect system.
The nacelle area is the area where automatic fire detection system is utilized to
detect a fire and provide visual indication to the operator.
FIRE PROTECTION
GENERAL
DESCRIPTION
The detection system components provide a method to detect a fire or an
overheat condition.
The detection system contains sensing element in the nacelle, an electronic
control in the tailcone, and visual indications on the fire tray, which is attached
to the glare shield.
FIRE PROTECTION
DETECTION SYSTEM
GENERAL
A fire detect sensor cable (UD001 left and UE001 right) is installed on each
engine.
The flexible stainless steel cable is attached to the engine and to tubing using
clamps and grommets.
FIRE PROTECTION
DETECTING SYSTEM
GENERAL
The cable clamps attach to the engine using existing engine component
fasteners.
The fire detection system detects a fire or overheat condition in the left or right
engine compartment.
FIRE PROTECTION
DETECTING SYSTEM
GENERAL
A fire warning indicator (light) is used to alert the operator when either
condition exists.
The aircraft is equipped with a detection system in each engine
compartment.
The installation are typical: therefore, the description, operation,
troubleshooting and maintenance practices apply to both installations.
FIRE PROTECTION
DETECTING SYSTEM
DETECTION SENSOR
The sensing cable is a 215.0 inch (5.46 m) flexible stainless steel tube which contains
a single wire centered in a highly compacted semiconductor material.
The semiconductor material holds the single wire centered as the cable is bent and
looped during installation.
FIRE PROTECTION
DETECTING SYSTEM
DETECTING SENSOR
The cable is hermetically sealed and has fireproof connector at each end.
CAUTION
Extreme care should be exercised during maintenance not to twist, kink or dent the
sensing loop element.
FIRE PROTECTION
DETECTING SYSTEM
OPERATION
The temperature sensitive element of the sensor cable is a semiconductor
coaxial cable having a homogeneous mass.
The cable is interconnected to form a closed loop and form one leg of a
Wheatstone bridge.
FIRE PROTECTION
DETECTING SYSTEM
OPERATION
With increasing temperature, the resistance of the cable decreases.
When the cable passes through null, sufficient current of the proper polarity actuates
the null detector which in turn operates a magnetic relay which actuates the fire
warning indicator.
FIRE PROTECTION
CONTROL UNIT
GENERAL
There are two detection control units (UT021 left and UT020 right) located in the tail
cone on the aft side of the aft baggage compartment wall.
It is accessible through the forward tail cone access door.
FIRE PROTECTION
CONTROL UNIT
CONTROL ASSEMBLY
The control assembly incorporates two Wheatstone bridge circuits.
The fire warning bridge is used to detect a fire or overheat condition in the engi8ne
nacelle.
The short discriminating bridge is used to detect a short in the sensor cable.
FIRE PROTECTION
CONTROL UNIT
CONTROL ASSEMBLY
The two bridge circuits share some resistors in the control assembly and they share
the sensor cable.
The control assembly disables the short discriminating lockout circuit by
disconnecting its output and simultaneously energizing the fire warning indicator.
FIRE PROTECTION
INDICATING LIGHTS
Indicating lights are provided to warn the pilot in the event of a fire in an engine
compartment, and to indicate when the fire extinguishing bottles are armed.
Indicating light assemblies have dual function.
FIRE PROTECTION
INDICATING LIGHTS
The fire warning light assembly contains a switch which arms the fire extinguisher
switch and closes the firewall fuel shutoff and hyd shutoff valves.
The bottle armed light assembly contains a switch that discharges the fire
extinguishing container.
FIRE PROTECTION
INDICATING LIGHTS
The right and left indicating lights are identical.
Removal procedures are typical for right and left light assemblies.
Lamp replacement can be accomplished without removing light assemblies.
FIRE PROTECTION
EXTINGUISHING SYSTEM
GENERAL
This section provides maintenance information on fire extinguishing.
The nacelle fire extinguishing is the main subject covered.
The portable fire extinguishers, which are associated with he cabin interior, are also
described in this section.
FIRE PROTECTION
EXTINGUISHING SYSTEM
NACELLE FIRE EXTINGUISHING
Two fixed fire extinguishing bottles are installed in the tail cone.
Each bottle has an extinguishing agent deployment tube to supply
the extinguishing agent to either the left engine or the right engine.
Therefore, either one or both bottles may be fired into either the left
or the right nacelle.
FIRE PROTECTION
EXTINGUISHING SYSTEM
NACELLE FIRE EXTINGUISHING
Controls for releasing the extinguishing agent are in the fire tray
attached to the glare shield.
The operator is signaled by the fire detection system by illuminating
indicators as to the condition in the nacelle.
The extinguishing controls also illuminate to aid the operator in
releasing the extinguishing agent.
FIRE PROTECTION
EXTINGUISHING SYSTEM
FIRE EXTINGUISHING BOTTLES
The two engine fire extinguisher bottles are located in the
tail cone.
The bottles store the extinguishing agent under pressure
until released by fire extinguishing discharge action.
Each bottle provides one extinguishing shot.
FIRE PROTECTION
EXTINGUISHING SYSTEM
FIRE EXTINGUISHER BOTTLES
The bottles are identical and consist of an 86-cubic inch spherical
steel container.
Steel container with a temperature compensated pressure switch,
a combined safety outlet and two discharge valves.
Fire extinguishing agent is CBrF3 (monobromotrifluoromethane.)
FIRE PROTECTION
EXTINGUISHING SYSTEM
FIRE EXTINGUISHER BOTTLES
The bottles are super pressurized at room temperature with dry
nitrogen.
The extinguishing agent is non corrosive.
When container pressure drops below 500 PSIG, ±30 PSIG at
70°F the switch will close and the FIRE EXT BOTTLE LOW light
will illuminate.
FIRE PROTECTION
EXTINGUISHING SYSTEM
FIRE EXTINGUISHER BOTTLES
The extinguisher utilizes a combination fill fitting and safety
relief assembly.
If the ambient temperature should rise abnormally, a fusible
check valve within the fill fitting melts.
This relieves the contents of the container through the fill
fitting.
FIRE PROTECTION
EXTINGUISHING SYSTEM
FIRE EXTINGUISHER EXPLOSIVE CARTRIDGES
The fire extinguisher explosive cartridges are electrically fired
and provide a means for controlling the release of the fire
extinguishing agent.
When actuated, the cartridge produces a high pressure which
ruptures the housing assembly.
The pressurized agent unseats the plug, releasing the agent
into and through the deployment tubes.
FIRE PROTECTION
EXTINGUISHING SYSTEM
FIRE EXTINGUISHER DEPLOYMENT TUBES
The fire extinguisher deployment tubes disperse the released
extinguishing agent from the bottles to the selected fire area.
Each left and right engine compartment area is served by an
individual deployment tube system.
FIRE PROTECTION
EXTINGUISHING SYSTEM
FIRE EXTINGUISHING DISCHARGE CONTROLS
Fire extinguishing discharge controls provide the crew
with the means to select and discharge from either fire
extinguisher container to either engine compartment.
The number 1 and number 2 engine fire extinguisher
switches are located on the fire tray.
FIRE PROTECTION
EXTINGUISHING SYSTEM
FIRE EXTINGUISHING DISCHARGE CONTROLS
To initiate discharge action for either engine compartment
after a fire warning light illuminates.
Raise the guard over the respective LH ENGINE FIRE or
RH ENGINE FIRE switch and press.
This action will close the fuel shutoff valve and hydraulic
shutoff valve.
FIRE PROTECTION
EXTINGUISHING SYSTEM
FIRE EXTINGUISHING DISCHARGE CONTROLS
When raise the guard then illuminate the BOTTLE 1 ARMED
PUSH and BOTTLE 2 ARMED PUSH lights.
It provides electrical power to the BOTTLE 1 ARMED PUSH
and BOTTLE 2 ARMED PUSH discharge switches.
Upon actuation a voltage of 28 VDC is applied to the cartridge.
FIRE PROTECTION
EXTINGUISHING SYSTEM
FIRE EXTINGUISHING DISCHARGE CONTROLS
If the fire Warning Light stays on, indicating fire is still present,
the remaining fire extinguishing switch may be actuated.
WARNING
When fire extinguisher discharge switches must be operated for
troubleshooting, make certain all circuits are isolated from the
bottle explosive cartridges to prevent accidental discharge.
FIRE PROTECTION
EXTINGUISHING SYSTEM
PORTABLE EXTINGUISHING
Two portable hand fire extinguishers are installed in the
aircraft.
One extinguisher is located in the cockpit on the copilot‘s
seat (accessible by either the pilot or copilot).
The other extinguisher is locate in the cabin accessible to
all the passengers.
FIRE PROTECTION
EXTINGUISHING SYSTEM
PORTABLE EXTINGUISHING
The cabin extinguisher is mounted to the floor just forward
of the divider at FS 342.75.
Both extinguisher are mounted in a quick release mounting
bracket painted red.
The bracket assembly is screw mounted.
FIRE PROTECTION
EXTINGUISHING SYSTEM
PORTABLE EXTINGUISHING
The portable extinguishers are pressurized bottles containing
a Halon Type 1211 extinguishing agent.
The bottles have an actuating valve that is operated by hand.
The extinguishers are rated for Class B and C fires and may
be recharged at any locally approved fire equipment service
shop.
FIRE PROTECTION
EXTINGUISHING SYSTEM
PORTABLE EXTINGUISHING
Servicing the extinguishers consists of checking the gage to
verify that normal pressure is maintained.
NOTE
After use, the extinguisher must be charged immediately.
replacement of the extinguishers (Halon 1211) should only
be an identical extinguisher.
QUESTIONS
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