Fire Protection R 01

8/8/2019 Fire Protection R 01

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PT. METRO BATAVIAPT. METRO BATAVIADirectorate of OperationalDirectorate of Operational

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737737--300/400300/400

FIRE PROTECTIONFIRE PROTECTION

NextNextMain MenuMain Menu QuitQuit




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Control StandControl Stand

Overheat/Fire Protection PanelOverheat/Fire Protection Panel




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Overheat/Fire Protection PanelOverheat/Fire Protection Panel-- SwitchesSwitches --

Engine Fire Warning Switches:Engine Fire Warning Switches:

IlluminatedIlluminated ± ±

Indicates a fire condition exists in the respective engine.Indicates a fire condition exists in the respective engine.

Automatically unlocks engine fire warning switch.Automatically unlocks engine fire warning switch.

FIRE WARN lights illuminate.FIRE WARN lights illuminate. Fire warning bell sounds.Fire warning bell sounds.

Note: The engine fire warning switches also illuminate during an OVHT/FIRE test.Note: The engine fire warning switches also illuminate during an OVHT/FIRE test.




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Engine Fire Warning Switches:Engine Fire Warning Switches:

The engine fire warning switches are mechanically locked ³down´ when no fire signal exists.The engine fire warning switches are mechanically locked ³down´ when no fire signal exists.

The following is a list of items that occur when an engine fire warning switch is ³pulledThe following is a list of items that occur when an engine fire warning switch is ³pulled--up´:up´:

Allows the engine fire warning switch to be rotated.Allows the engine fire warning switch to be rotated. Arms one discharge squib on each engine fire extinguisher bottle.Arms one discharge squib on each engine fire extinguisher bottle.

Closes respective engine fuel shutoff valve, hydraulic shutoff valve, and engine bleed air valve.Closes respective engine fuel shutoff valve, hydraulic shutoff valve, and engine bleed air valve.

Trips the respective generator control relay and circuit breaker.Trips the respective generator control relay and circuit breaker.

Thrust reverser isolation valve closes, thereby disabling the thrust reverser.Thrust reverser isolation valve closes, thereby disabling the thrust reverser.

Deactivates the respective engine driven pump hydraulic LOW PRESSURE light.Deactivates the respective engine driven pump hydraulic LOW PRESSURE light.

Rotating the engine fire warning switch left or right will discharge the related engine fire bottleRotating the engine fire warning switch left or right will discharge the related engine fire bottle

extinguishing agent into an area above the center of the respective engine (1 or 2).extinguishing agent into an area above the center of the respective engine (1 or 2).




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APU Fire Warning Switch:APU Fire Warning Switch:


Indicates a fire condition exists in the APU.Indicates a fire condition exists in the APU.

Automatically unlocks APU fire warning switch.Automatically unlocks APU fire warning switch.

FIRE WARN lights illuminate.FIRE WARN lights illuminate. Fire warning bell sounds.Fire warning bell sounds.

APU fire warning horn in main gear wheel well sounds (if aircraft is on the ground).APU fire warning horn in main gear wheel well sounds (if aircraft is on the ground).

APU fire warning light flashes (located on APU ground control panel in main gear wheel well).APU fire warning light flashes (located on APU ground control panel in main gear wheel well).

Note: The APU fire warning switch also illuminates during an OVHT/FIRE test.Note: The APU fire warning switch also illuminates during an OVHT/FIRE test.




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APU Fire Warning Switch:APU Fire Warning Switch:

The APU fire warning switch is mechanically locked ³down´ when no fire signal exists.The APU fire warning switch is mechanically locked ³down´ when no fire signal exists.

The following is a list of items that occur when the APU fire warning switch is ³pulledThe following is a list of items that occur when the APU fire warning switch is ³pulled--up´:up´:

Allows the APU fire warning switch to be rotated.Allows the APU fire warning switch to be rotated. Arms the discharge squib on the APU fire extinguisher bottle.Arms the discharge squib on the APU fire extinguisher bottle.

Closes APU fuel shutoff valve, APU fuel solenoid valve, APU bleed air valve, and APU air inlet door.Closes APU fuel shutoff valve, APU fuel solenoid valve, APU bleed air valve, and APU air inlet door.

Trips the generator control relay and circuit breaker.Trips the generator control relay and circuit breaker.

Provides a backup for the automatic shutdown feature.Provides a backup for the automatic shutdown feature.

Rotating the APU fire warning switch left or right will discharge the APU fire bottle extinguishingRotating the APU fire warning switch left or right will discharge the APU fire bottle extinguishing

agent into the APU shroud.agent into the APU shroud.




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OVHT DET Switches (ThreeOVHT DET Switches (Three--position):position):

NORMALNORMAL ± ±

Both overheat/fire detector loops (³A´ and ³B´) are active.Both overheat/fire detector loops (³A´ and ³B´) are active.

³A´³A´ ± ±Overheat/fire detector loop ³A´ is the selected active loop on respective engine.Overheat/fire detector loop ³A´ is the selected active loop on respective engine.

³B´³B´ ± ±

Overheat/fire detector loop ³B´ is the selected active loop on respective engine.Overheat/fire detector loop ³B´ is the selected active loop on respective engine.




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FAULT/INOP and OVHT/FIRE TEST Switch (springFAULT/INOP and OVHT/FIRE TEST Switch (spring--loaded to center):loaded to center):

FAULT/INOPFAULT/INOP ± ±

Tests the fault detection circuits for both engines and the APU.Tests the fault detection circuits for both engines and the APU.

OVHT/FIREOVHT/FIRE ± ±Tests both overheat/fire detection loops (³A´ and ³B´) on both engines. Also tests the APU andTests both overheat/fire detection loops (³A´ and ³B´) on both engines. Also tests the APU and

wheel well fire detector loops.wheel well fire detector loops.

Note: A detailed description of the FAULT/INOP and OVHT/FIRE test will be discussed later in thisNote: A detailed description of the FAULT/INOP and OVHT/FIRE test will be discussed later in this

presentation.presentation.




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BELL CUTOUT Switch:BELL CUTOUT Switch:

PushPush ± ±

Extinguishes both FIRE WARN lights.Extinguishes both FIRE WARN lights.

Silences fire warning bell.Silences fire warning bell.

Silences remote APU fire warning horn (only if aircraft on the ground).Silences remote APU fire warning horn (only if aircraft on the ground). Resets fire warning system for additional fire warnings.Resets fire warning system for additional fire warnings.




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EXT TEST Switch (springEXT TEST Switch (spring--loaded to center):loaded to center):

When positioned to 1 or 2, tests to ensure circuit continuity is normal from the engine and APUWhen positioned to 1 or 2, tests to ensure circuit continuity is normal from the engine and APU

fire extinguisher bottle squibs to the respective fire warning switch.fire extinguisher bottle squibs to the respective fire warning switch.

Note: All fire extinguisher bottle squibs are powered by the hot battery bus.Note: All fire extinguisher bottle squibs are powered by the hot battery bus.




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Overheat/Fire Protection PanelOverheat/Fire Protection Panel-- LightsLights --

ENG 1 OVERHEAT and ENG 2 OVERHEAT Lights:ENG 1 OVERHEAT and ENG 2 OVERHEAT Lights:


Indicates an overheat condition in the respective engine.Indicates an overheat condition in the respective engine.

Automatically unlocks respective engine fire warning switch.Automatically unlocks respective engine fire warning switch.

MASTER CAUTION and OVHT/DET system annunciator lights illuminate.MASTER CAUTION and OVHT/DET system annunciator lights illuminate.

Note: The ENG OVERHEAT lights also illuminate during an OVHT/FIRE test.Note: The ENG OVERHEAT lights also illuminate during an OVHT/FIRE test.




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WHEEL WELL Fire Warning Light:WHEEL WELL Fire Warning Light:


Indicates a fire in the main gear wheel well.Indicates a fire in the main gear wheel well.

FIRE WARN lights illuminate.FIRE WARN lights illuminate.

Fire warning bell sounds.Fire warning bell sounds.

Note: The WHEEL WELL fire warning light also illuminates during an OVHT/FIRE test if the wheelNote: The WHEEL WELL fire warning light also illuminates during an OVHT/FIRE test if the wheel

well fire loop is normal (see note below).well fire loop is normal (see note below).

Note: The fire detector loop in the wheel well is AC powered (transfer bus 1). Therefore, ACNote: The fire detector loop in the wheel well is AC powered (transfer bus 1). Therefore, AC

power on the aircraft is required to detect a wheel well fire and to test the wheel well fire detector power on the aircraft is required to detect a wheel well fire and to test the wheel well fire detector

loop. Also, the nose gear wheel well does not incorporate a fire detection system.loop. Also, the nose gear wheel well does not incorporate a fire detection system.




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FAULT Light:FAULT Light:


IndicatesIndicates bothboth overheat/fire detector loops (³A´ and ³B´) have failed on an engine (with relatedoverheat/fire detector loops (³A´ and ³B´) have failed on an engine (with related

OVHT DET switch in NORMAL).OVHT DET switch in NORMAL).

Indicates the selected overheat/fire detector loop (³A´ or ³B´) has failed on one engine (withIndicates the selected overheat/fire detector loop (³A´ or ³B´) has failed on one engine (withrelated OVHT DET switch in ³A´ or ³B´).related OVHT DET switch in ³A´ or ³B´).

During an OVHT/FIRE test, indicates an overheat/fire detector loop(s) (³A´ or ³B´) has failed onDuring an OVHT/FIRE test, indicates an overheat/fire detector loop(s) (³A´ or ³B´) has failed on

one or both engines (with related OVHT DET switch in NORMAL).one or both engines (with related OVHT DET switch in NORMAL).

Note: FAULT light also illuminates during a FAULT/INOP test if fault detection circuits are normal.Note: FAULT light also illuminates during a FAULT/INOP test if fault detection circuits are normal.

Note: The MASTER CAUTION and OVHT/DET system annunciator lightsNote: The MASTER CAUTION and OVHT/DET system annunciator lights DO NOTDO NOT illuminate whenilluminate when

the FAULT light illuminates.the FAULT light illuminates.




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APU DET INOP Light:APU DET INOP Light:


Indicates APU fire detector loop has failed.Indicates APU fire detector loop has failed.

MASTER CAUTION and OVHT/DET system annunciator lights illuminate.MASTER CAUTION and OVHT/DET system annunciator lights illuminate.

Note: APU DET INOP light also illuminates during a FAULT/INOP test if the APU fire detector loopNote: APU DET INOP light also illuminates during a FAULT/INOP test if the APU fire detector loop

is normal.is normal.




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APU BOTTLE DISCHARGED Light:APU BOTTLE DISCHARGED Light:


Indicates APU fire extinguisher bottle has discharged.Indicates APU fire extinguisher bottle has discharged.

Note: The MASTER CAUTION system does not illuminate when the APU BOTTLE DISCHARGEDNote: The MASTER CAUTION system does not illuminate when the APU BOTTLE DISCHARGEDlight illuminates.light illuminates.




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L and R BOTTLE DISCHARGED Lights:L and R BOTTLE DISCHARGED Lights:


Indicates respective engine fire extinguisher bottle has discharged.Indicates respective engine fire extinguisher bottle has discharged.

Note: The MASTER CAUTION system does not illuminate when the L or R BOTTLE DISCHARGEDNote: The MASTER CAUTION system does not illuminate when the L or R BOTTLE DISCHARGEDlights illuminates.lights illuminates.




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EXT TEST Lights (3 green):EXT TEST Lights (3 green):


Extinguisher test switch has been positioned to 1 or 2 and circuit continuity is normal from theExtinguisher test switch has been positioned to 1 or 2 and circuit continuity is normal from the

engine and APU fire extinguisher bottle squibs to the respective fire warning switch.engine and APU fire extinguisher bottle squibs to the respective fire warning switch.




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Overheat/Fire Protection PanelOverheat/Fire Protection Panel(side view)(side view)

Fire Warning Switch Override:Fire Warning Switch Override:

One located under each fire warning switch.One located under each fire warning switch.

PushPush ± ±

Manually unlocks the respective fire warningManually unlocks the respective fire warningswitch, which then allows the switch to beswitch, which then allows the switch to be

³pulled³pulled--up.´ This action may be necessary if up.´ This action may be necessary if

the switch fails to unlock during an enginethe switch fails to unlock during an engine

overheat or fire condition.overheat or fire condition.




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Fire Warning SystemFire Warning SystemFIRE WARN lights:FIRE WARN lights:


Indicates a fire warning in the engine(s), mainIndicates a fire warning in the engine(s), main

gear wheel well, or APU. Lights remaingear wheel well, or APU. Lights remain

illuminated as long as the fire condition exists or illuminated as long as the fire condition exists or

until the crew resets the fire warning system.until the crew resets the fire warning system. A fire system test is being performed.A fire system test is being performed.


Remote APU fire warning horn sounds during anRemote APU fire warning horn sounds during an

APU fire if the aircraft is on the ground.APU fire if the aircraft is on the ground.

PushPush ± ±

Extinguishes both FIRE WARN lights.Extinguishes both FIRE WARN lights.

Silences fire warning bell.Silences fire warning bell. Silences remote APU fire warning hornSilences remote APU fire warning horn (ground only).(ground only).

Resets fire warning system for additional fireResets fire warning system for additional fire

warnings.warnings.

Note: Pushing the BELL CUTOUT switch on theNote: Pushing the BELL CUTOUT switch on the

overheat/fire protection panel results in the sameoverheat/fire protection panel results in the same

four items listed above.four items listed above.

Left SideLeft Side

Right SideRight Side

Listen to theListen to the

fire warning bellfire warning bell

Listen to the APUListen to the APU

fire warning hornfire warning horn




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APU Ground Control Panel andAPU Ground Control Panel and

Fire Warning HornFire Warning Horn

Located in the main gear wheel wellLocated in the main gear wheel well




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Fire Warning HornFire Warning HornAPU Fire Warning HORN CUTOUT Switch:APU Fire Warning HORN CUTOUT Switch:

PushPush ± ±

APU fire warning light (on ground control panel)APU fire warning light (on ground control panel)

stops flashing, but remains illuminated steadystops flashing, but remains illuminated steady

until the APU fire detector loop no longer detectsuntil the APU fire detector loop no longer detects

a fire condition.a fire condition. Extinguishes both FIRE WARN lights.Extinguishes both FIRE WARN lights.

Silences fire warning bell in flight deck.Silences fire warning bell in flight deck.

Silences remote APU fire warning horn.Silences remote APU fire warning horn.

Resets fire warning system for additional fireResets fire warning system for additional fire

warnings.warnings.




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Fire Warning HornFire Warning HornAPU Fire Control Handle:APU Fire Control Handle:

The normal position for the APU fire control handleThe normal position for the APU fire control handle

is ³up.ís ³up.´

The following is a list of items that occur when theThe following is a list of items that occur when the

APU fire control handle is ³pulledAPU fire control handle is ³pulled--down´:down´: Closes APU fuel shutoff valve, APU fuel solenoidCloses APU fuel shutoff valve, APU fuel solenoid

valve, APU bleed air valve, and APU air inlet door.valve, APU bleed air valve, and APU air inlet door.

Trips the generator control relay and circuitTrips the generator control relay and circuit

breaker.breaker.

Arms the APU BOTTLE DISCHARGE switch.Arms the APU BOTTLE DISCHARGE switch.




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Fire Warning HornFire Warning HornAPU BOTTLE DISCHARGE Switch:APU BOTTLE DISCHARGE Switch:

(spring(spring--loaded to center)loaded to center)

Once the APU BOTTLE DISCHARGE switch isOnce the APU BOTTLE DISCHARGE switch is

armed, toggling the switch (left or right) willarmed, toggling the switch (left or right) will

discharge the APU fire bottle extinguishing agentdischarge the APU fire bottle extinguishing agentinto the APU shroud.into the APU shroud.

Note: The APU BOTTLE DISCHARGE switch canNote: The APU BOTTLE DISCHARGE switch can

onlyonly be armed by ³pullingbe armed by ³pulling--down´ on APU firedown´ on APU fire

control handle. ³Pullingcontrol handle. ³Pulling--up´ on the APU fireup´ on the APU fire

warning switch it the flight deck does not arm thewarning switch it the flight deck does not arm the

APU BOTTLE DISCHARGE switch.APU BOTTLE DISCHARGE switch.




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Fire Warning HornFire Warning HornAPU Fire Warning Light:APU Fire Warning Light:

Illuminated flashingIlluminated flashing ± ±

Indicates a fire condition exists in the APU.Indicates a fire condition exists in the APU.

Recall that with an APU fire indication, theRecall that with an APU fire indication, the

following items also occur:following items also occur: Automatically unlocks APU fire warning switch.Automatically unlocks APU fire warning switch.

FIRE WARN lights illuminate.FIRE WARN lights illuminate.


APU fire warning horn in main gear wheel wellAPU fire warning horn in main gear wheel well

sounds (if aircraft is on the ground).sounds (if aircraft is on the ground).

Illuminated steadyIlluminated steady ± ±

Indicates APU fire warning HORN CUTOUT switchIndicates APU fire warning HORN CUTOUT switchhas been pushed following an APU fire indication.has been pushed following an APU fire indication.

Light remains illuminated steady until the APU fireLight remains illuminated steady until the APU fire

detector loop no longer detects a fire condition.detector loop no longer detects a fire condition.




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Fire Warning HornFire Warning HornAPU Fire Warning Horn:APU Fire Warning Horn:

Gives aural warning of fire condition in the APU.Gives aural warning of fire condition in the APU.

Horn is silenced by pushing the APU fire warningHorn is silenced by pushing the APU fire warning

HORN CUTOUT switch.HORN CUTOUT switch.

Horn is activeHorn is active onlyonly when aircraft is on the ground.when aircraft is on the ground.

Horn is deactivated while in flight.Horn is deactivated while in flight.

Listen to the APUListen to the APU

fire warning hornfire warning horn




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Lavatory Fire Extinguisher BottleLavatory Fire Extinguisher Bottle

and Temperature Indicator and Temperature Indicator

Located under the lavatory sinksLocated under the lavatory sinks




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and Temperature Indicator and Temperature Indicator Lavatory Fire Extinguisher Bottle:Lavatory Fire Extinguisher Bottle:

This fire bottle is a steel container with a diameter This fire bottle is a steel container with a diameter

of approximately 2.5 inches. The bottle is filledof approximately 2.5 inches. The bottle is filled

with approximately 10 cubic inches of Freon.with approximately 10 cubic inches of Freon.




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and Temperature Indicator and Temperature Indicator Lavatory Fire Extinguisher Bottle:Lavatory Fire Extinguisher Bottle:

Two discharge tubes extend from the bottom of theTwo discharge tubes extend from the bottom of the

fire bottle. One discharge tube terminates in thefire bottle. One discharge tube terminates in the

towel waste compartment and the other tubetowel waste compartment and the other tube

terminates under the lavatory sink. At the end of terminates under the lavatory sink. At the end of

each discharge tube is a fusible tip with a meltingeach discharge tube is a fusible tip with a meltingtemperature of 174temperature of 174°° F. When the temperature in theF. When the temperature in the

towel waste compartment or under the lavatorytowel waste compartment or under the lavatory

sink exceedssink exceeds 174174°° F, the associated fusible tip willF, the associated fusible tip will

melt and consequently the bottle discharges intomelt and consequently the bottle discharges into

the affected area. The fusible tips will change color the affected area. The fusible tips will change color

from black to silver to indicate the bottle hasfrom black to silver to indicate the bottle has

discharged.discharged.

Note: There is no indication in the flight deck thatNote: There is no indication in the flight deck that

the lavatory fire extinguisher bottle has discharged.the lavatory fire extinguisher bottle has discharged.

Also, on some aircraft, both discharge tubes mayAlso, on some aircraft, both discharge tubes may

terminate in the towel waste compartment.terminate in the towel waste compartment.




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and Temperature Indicator and Temperature Indicator Temperature Indicator Placard:Temperature Indicator Placard:

The temperature indicator placard is a thin vinylThe temperature indicator placard is a thin vinyl

plate containing four heat sensitive patches. Theplate containing four heat sensitive patches. The

patches will change from white to black in color patches will change from white to black in color

when the placard is exposed to temperatures fromwhen the placard is exposed to temperatures from

180180°° F toF to 250250°° F.F.

This concludes the general review of the fire protection system. The nextThis concludes the general review of the fire protection system. The next

section will discuss the fire protection system in greater detail. Clicksection will discuss the fire protection system in greater detail. Click Next Next to continue.to continue.




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Fire ProtectionSystem Description

The engines, APU, main gear wheel well, and lavatories all incorporate a fire detection system.

The engines also incorporate an overheat detection system. All the aforementioned areas

have their own fire extinguishing system, except the main gear wheel well.




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Engine Overheat and Fire DetectionEngine Overheat and Fire Detection

The engine overheat/fire detection system is known as a ³dualThe engine overheat/fire detection system is known as a ³dual--loop´ system. This ³dualloop´ system. This ³dual--

loop´ system consists of two identical overheat/fire detector loops. Both loops areloop´ system consists of two identical overheat/fire detector loops. Both loops arecapable of detecting an overheat or fire condition. The loops are referred to as loop ³Aćapable of detecting an overheat or fire condition. The loops are referred to as loop ³A´

and loop ³B.ánd loop ³B.´




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Loop ³A´ and loop ³B´ both consist of four sensing elements. Each sensing element is partLoop ³A´ and loop ³B´ both consist of four sensing elements. Each sensing element is part

of a continuous electrical resistance loop, with resistance varying inversely as a function of of a continuous electrical resistance loop, with resistance varying inversely as a function of temperature. In other words, as the temperature of the sensing element increases,temperature. In other words, as the temperature of the sensing element increases,

resistance decreases. The sensing elements run sideresistance decreases. The sensing elements run side--byby--side and are attached to a supportside and are attached to a support

tube. The power source for both overheat/fire detector loops is the battery bus.tube. The power source for both overheat/fire detector loops is the battery bus.

The four sensing elements are located in the following four areas of the engine: engineThe four sensing elements are located in the following four areas of the engine: engine

strut, upper fan, lower fan, and surrounding engine corestrut, upper fan, lower fan, and surrounding engine core

Engine strutEngine strut

elementelement

Upper fanUpper fan

elementelement

Lower fanLower fan

elementelement

ElementElement

surroundingsurrounding

engine coreengine core

See picture of See picture of

upper fan elementupper fan element




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With the OVHT DET switches positioned to NORMAL,With the OVHT DET switches positioned to NORMAL, bothboth loop ³A´ and loop ³B´ sensingloop ³A´ and loop ³B´ sensing

elements must agree on a overheat condition before an overheat signal is sent to the flight deck.elements must agree on a overheat condition before an overheat signal is sent to the flight deck.

With the OVHT DET switch positioned to ³A´ or ³B,´ the system operates as a single loopWith the OVHT DET switch positioned to ³A´ or ³B,´ the system operates as a single loopsystem. The selected loop will operate normally without the assistance of the nonsystem. The selected loop will operate normally without the assistance of the non--selected loopselected loop

and, if necessary, will send an overheat signal to the flight deck if it detects an overheatand, if necessary, will send an overheat signal to the flight deck if it detects an overheat

condition.condition.

The pictures above indicate which lights will be illuminated during an overheat condition on theThe pictures above indicate which lights will be illuminated during an overheat condition on the

No. 1 engine. The ENG 1 OVERHEAT light will remain illuminated until the temperature of theNo. 1 engine. The ENG 1 OVERHEAT light will remain illuminated until the temperature of the

detector loops drop below the predetector loops drop below the pre--determined limit.determined limit.




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With the OVHT DET switches positioned to NORMAL,With the OVHT DET switches positioned to NORMAL, bothboth loop ³A´ and loop ³B´ sensingloop ³A´ and loop ³B´ sensing

elements must agree on a fire condition before a fire signal is sent to the flight deck.elements must agree on a fire condition before a fire signal is sent to the flight deck.

With the OVHT DET switch positioned to ³A´ or ³B,´ the system operates as a single loopWith the OVHT DET switch positioned to ³A´ or ³B,´ the system operates as a single loopsystem. The selected loop will operate normally without the assistance of the nonsystem. The selected loop will operate normally without the assistance of the non--selectedselected

loop and, if necessary, will send a fire signal to the flight deck if it detects a fire condition.loop and, if necessary, will send a fire signal to the flight deck if it detects a fire condition.

The pictures above indicate which lights will be illuminated during a fire condition on theThe pictures above indicate which lights will be illuminated during a fire condition on the

No. 1 engine. The engine fire warning switch and ENG 1 OVERHEAT light will remainNo. 1 engine. The engine fire warning switch and ENG 1 OVERHEAT light will remain

illuminated until the temperature of the detector loops drop below the preilluminated until the temperature of the detector loops drop below the pre--determined limit.determined limit.




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Recall that the FAULT light monitors both loop ³A´ and ³B´ on both engines. With a failureRecall that the FAULT light monitors both loop ³A´ and ³B´ on both engines. With a failure

of one loop on either engine, and the OVHT DET switches in NORMAL, the affected loop isof one loop on either engine, and the OVHT DET switches in NORMAL, the affected loop is

automatically ³deselected´ and the system operates as a single loop system. The crew willautomatically ³deselected´ and the system operates as a single loop system. The crew will

still be warned of an overheat or fire condition even with one loop inoperative. There is nostill be warned of an overheat or fire condition even with one loop inoperative. There is no

flight deck indication of a single loop failure, i.e. the FAULT lightflight deck indication of a single loop failure, i.e. the FAULT light does notdoes not illuminate.illuminate.

If both loop ³A´ and ³B´ were to fail on either engine, the FAULT illuminates. The failure of If both loop ³A´ and ³B´ were to fail on either engine, the FAULT illuminates. The failure of

both loops renders the overheat/fire detection system inoperative on the affected engine.both loops renders the overheat/fire detection system inoperative on the affected engine.

The illumination of the FAULT lightThe illumination of the FAULT light does notdoes not illuminate the master caution or any systemilluminate the master caution or any system

annunciator.annunciator.




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Overheat, Fire, and Fault Light LogicOverheat, Fire, and Fault Light Logic

This table indicates which overheat/fire detection warning lights will be illuminated under variousThis table indicates which overheat/fire detection warning lights will be illuminated under various

conditions assuming both loops are operative. For example, if loop ³A´ on the No. 1 engine wasconditions assuming both loops are operative. For example, if loop ³A´ on the No. 1 engine was

detecting an overheat condition and loop ³B´ on the No. 1 engine was detecting a fire condition, thedetecting an overheat condition and loop ³B´ on the No. 1 engine was detecting a fire condition, the

ENG 1 OVERHEAT light would be illuminated. This is becauseENG 1 OVERHEAT light would be illuminated. This is because bothboth loops have at least agreed uponloops have at least agreed upon

an overheat condition, yet do not agree on a fire condition.an overheat condition, yet do not agree on a fire condition.

LOOP ³A´LOOP ³A´

LL

OOOO

PP

³B´³B´

LOOPLOOP

CONDITIONCONDITIONFIREFIRE OVERHEATOVERHEAT NORMALNORMAL FAULTFAULT

POWERPOWER

FAILUREFAILURE

FIREFIREFIREFIRE

OVERHEATOVERHEATOVERHEATOVERHEAT NONENONE

FIREFIRE

OVERHEATOVERHEATFAULTFAULT

OVERHEATOVERHEAT OVERHEATOVERHEAT OVERHEATOVERHEAT NONENONE OVERHEATOVERHEAT FAULTFAULT

NORMALNORMAL NONENONE NONENONE NONENONE NONENONE FAULTFAULT

FAULTFAULTFIREFIRE

OVERHEATOVERHEATOVERHEATOVERHEAT NONENONE FAULTFAULT FAULTFAULT

POWERPOWER

FAILUREFAILUREFAULTFAULT FAULTFAULT FAULTFAULT FAULTFAULT FAULTFAULT




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Overheat, Fire, and Fault Light LogicOverheat, Fire, and Fault Light Logic

This table indicates which overheat/fire detection warning lights will be illuminated under variousThis table indicates which overheat/fire detection warning lights will be illuminated under various

conditions assuming one loop inoperative. For example, if loop ³A´ on the No. 1 engine wasconditions assuming one loop inoperative. For example, if loop ³A´ on the No. 1 engine was

inoperative and loop ³B´ on the No. 1 engine was sensing a fire condition, the No. 1 fire warning switchinoperative and loop ³B´ on the No. 1 engine was sensing a fire condition, the No. 1 fire warning switch

and the ENG 1 OVERHEAT light would be illuminated. Because one loop is inoperative, the operatingand the ENG 1 OVERHEAT light would be illuminated. Because one loop is inoperative, the operating

loop acts as a single loop system and sends the appropriate warning signals to the fight deck.loop acts as a single loop system and sends the appropriate warning signals to the fight deck.

OPERATINGOPERATING

LOOPLOOP

CONDITIONCONDITION

FIREFIRE OVERHEATOVERHEAT NORMALNORMAL FAULTFAULTPOWERPOWER

FAILUREFAILURE

FLIGHT DECKFLIGHT DECKINDICATIONINDICATION

FIREFIRE

OVERHEATOVERHEATOVERHEATOVERHEAT NONENONE FAULTFAULT FAULTFAULT




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Engine Fire ExtinguishingEngine Fire Extinguishing

In order to combat an engine fire, the respective fire warning switch must be ³pulledIn order to combat an engine fire, the respective fire warning switch must be ³pulled--up´ andup´ and

rotated left or right. The fire warning switches are normally locked down to prevent anrotated left or right. The fire warning switches are normally locked down to prevent an

inadvertent shutdown of an engine. They are automatically unlocked when the system detectsinadvertent shutdown of an engine. They are automatically unlocked when the system detects

an overheat or fire condition. If the fire warning switches fail to unlock, they may be manuallyan overheat or fire condition. If the fire warning switches fail to unlock, they may be manually

unlocked via the fire warning switch override (located under each fire warning switch).unlocked via the fire warning switch override (located under each fire warning switch).




Slide 39 of 57


The following is a list of items that occur when an engine fire warning switch is ³pulledThe following is a list of items that occur when an engine fire warning switch is ³pulled--up´:up´:

Allows the engine fire warning switch to be rotated.Allows the engine fire warning switch to be rotated.

Arms one discharge squib on each engine fire extinguisher bottle.Arms one discharge squib on each engine fire extinguisher bottle.

Closes respective engine fuel shutoff valve, hydraulic shutoff valve, and engine bleed air valve.Closes respective engine fuel shutoff valve, hydraulic shutoff valve, and engine bleed air valve.

Trips the respective generator control relay and circuit breaker.Trips the respective generator control relay and circuit breaker.

Thrust reverser isolation valve closes, thereby disabling the thrust reverser.Thrust reverser isolation valve closes, thereby disabling the thrust reverser.

Deactivates the respective engine driven pump hydraulic LOW PRESSURE light.Deactivates the respective engine driven pump hydraulic LOW PRESSURE light.




Slide 40 of 57


There are two engine fire bottles located in the main gear wheel well. Either or both fire bottlesThere are two engine fire bottles located in the main gear wheel well. Either or both fire bottles

are capable of discharging their extinguishing agent to either engine. Two squib cartridges areare capable of discharging their extinguishing agent to either engine. Two squib cartridges are

attached to the discharge ports of both fire bottles. Rotating an engine fire warning switch ³firesáttached to the discharge ports of both fire bottles. Rotating an engine fire warning switch ³fires´

the appropriate squib on the selected bottle, which in turn ruptures a retaining disc and releasesthe appropriate squib on the selected bottle, which in turn ruptures a retaining disc and releases

the extinguishing agent into the respective engine. When the pressure in the fire bottle dropsthe extinguishing agent into the respective engine. When the pressure in the fire bottle dropsbelow a prebelow a pre--determined limit, the respective BOTTLE DISCHARGED light illuminates.determined limit, the respective BOTTLE DISCHARGED light illuminates.

See picture of See picture of

engine fire bottlesengine fire bottles




Slide 41 of 57

Engine Fire ExtinguishingEngine Fire ExtinguishingEngine Fire ExtinguishingLet¶s assume that an engine fire existson the No. 1 engine«

Rotating the No. 1 engine fire warning

switch to the left electrically ³fires´ the

No. 1 squib on the left bottle and

discharges the extinguishing agent into

the No. 1 engine. If the engine fire does

not extinguish, the other option is torotate the No. 1 engine fire warning

switch to the right. This ³fires´ the No. 1

squib on the right bottle and discharges

the extinguishing agent into the No. 1

engine. Remember, ONLY two engine fire

extinguishing bottles are installed!

Rotating the No. 2 engine fire warningswitch acts in the same manner as the

No. 1 engine fire warning switch, except

the extinguishing agent is discharged

into the No. 2 engine.

LeftLeft

firefire

bottlebottle

RightRight

firefire

bottlebottle

No. 1 engine No. 2 engine

No. 2

squib

No. 1

squib

No. 2

squib

No. 1

squib




Slide 42 of 57

APU Fire DetectionAPU Fire Detection

A single fire detector loop is installed on the APU and consists of three sensing elements.A single fire detector loop is installed on the APU and consists of three sensing elements.

The sensing elements are located in the APU engine and exhaust areas. The sensingThe sensing elements are located in the APU engine and exhaust areas. The sensing

elements function similar to the engine overheat/fire detector loops, i.e. as the temperatureelements function similar to the engine overheat/fire detector loops, i.e. as the temperature

of the sensing element increases, resistance decreases. The power source for the fireof the sensing element increases, resistance decreases. The power source for the fire

detector loop is the battery bus.detector loop is the battery bus.




Slide 43 of 57


When the temperature of the sensing element rises to a preWhen the temperature of the sensing element rises to a pre--

determined limit, the APU fire warning switch illuminates, the firedetermined limit, the APU fire warning switch illuminates, the fire

warning bell sounds, and the APU automatically shuts down.warning bell sounds, and the APU automatically shuts down.

These pictures indicate which lights will be illuminated during anThese pictures indicate which lights will be illuminated during an

APU fire condition. In addition, the APU fire warning light on theAPU fire condition. In addition, the APU fire warning light on the

ground control panel flashes and the APU fire warning hornground control panel flashes and the APU fire warning horn

sounds (if aircraft is on the ground).sounds (if aircraft is on the ground).

The APU fire warning switch and the APU fire warning light willThe APU fire warning switch and the APU fire warning light will

remain illuminated until the temperature of the detector loopremain illuminated until the temperature of the detector loop

drops below the predrops below the pre--determined limit.determined limit.




Slide 44 of 57


A fault monitoring system is installed to ensure that the APU fire detector loop isA fault monitoring system is installed to ensure that the APU fire detector loop is

functioning properly. If the loop fails, the APU DET INOP light illuminates as well as thefunctioning properly. If the loop fails, the APU DET INOP light illuminates as well as the

MASTER CAUTION and OVHT/DET system annunciator.MASTER CAUTION and OVHT/DET system annunciator.




Slide 45 of 57

APU Fire ExtinguishingAPU Fire Extinguishing

In order to combat an APU fire, the APU fire warning switch must be ³pulledIn order to combat an APU fire, the APU fire warning switch must be ³pulled--up´ andup´ and

rotated left or right. The APU fire warning switch is normally locked down to prevent anrotated left or right. The APU fire warning switch is normally locked down to prevent an

inadvertent shutdown of the APU. It is automatically unlocked when the system detects ainadvertent shutdown of the APU. It is automatically unlocked when the system detects a

fire condition in the APU. If the fire switch fails to unlock, it may be manually unlocked viafire condition in the APU. If the fire switch fails to unlock, it may be manually unlocked via

the fire warning switch override (located under the APU fire warning switch).the fire warning switch override (located under the APU fire warning switch).




Slide 46 of 57


The following is a list of items that occur when the APU fire warning switch is ³pulledThe following is a list of items that occur when the APU fire warning switch is ³pulled--up´:up´:

Allows the APU fire warning switch to be rotated.Allows the APU fire warning switch to be rotated.

Provides a backup for the automatic shutdown feature.Provides a backup for the automatic shutdown feature.

Closes APU fuel shutoff valve, APU fuel solenoid valve, APU bleed air valve, and APU air inlet door.Closes APU fuel shutoff valve, APU fuel solenoid valve, APU bleed air valve, and APU air inlet door.

Trips the generator control relay and circuit breaker.Trips the generator control relay and circuit breaker.

Arms the discharge squib on the APU fire extinguisher bottle.Arms the discharge squib on the APU fire extinguisher bottle.




Slide 47 of 57


There is one APU fire extinguisher bottle located in the empennage section of the aircraft.There is one APU fire extinguisher bottle located in the empennage section of the aircraft.

One squib cartridge is attached to the discharge port of the fire bottle. Rotating the APUOne squib cartridge is attached to the discharge port of the fire bottle. Rotating the APU

fire warning switch ³fires´ the squib which in turn ruptures a retaining disc and releasesfire warning switch ³fires´ the squib which in turn ruptures a retaining disc and releases

the extinguishing agent into the APU. When the pressure in the fire bottle drops below athe extinguishing agent into the APU. When the pressure in the fire bottle drops below a

prepre--determined limit, the APU BOTTLE DISCHARGED light illuminates.determined limit, the APU BOTTLE DISCHARGED light illuminates.




Slide 48 of 57

APU Fire Bottle IndicatorsAPU Fire Bottle Indicators

Located on the lower right side of the fuselage, under the APU air inlet door, are two APULocated on the lower right side of the fuselage, under the APU air inlet door, are two APU

fire bottle indicators. The indicators are small red and yellow plastic discs held in place byfire bottle indicators. The indicators are small red and yellow plastic discs held in place by

a snapa snap--ring. The red disc is the thermal relief indicator and the yellow disc is the systemring. The red disc is the thermal relief indicator and the yellow disc is the system

discharge indicator.discharge indicator.




Slide 49 of 57




Slide 50 of 57

APU Fire Bottle IndicatorsAPU Fire Bottle Indicators

If the internal temperature of the fire extinguisher bottle exceeds approximately 266If the internal temperature of the fire extinguisher bottle exceeds approximately 266°° F., theF., the

extinguishing agent will be expelled into a discharge line which leads to the thermal relief extinguishing agent will be expelled into a discharge line which leads to the thermal relief

indicator (red disc). The pressure from the bottle will rupture the thermal relief indicator andindicator (red disc). The pressure from the bottle will rupture the thermal relief indicator and

all the extinguishing agent is dumped overboard.all the extinguishing agent is dumped overboard.

When the APU fire warning switch is rotated in either direction, the extinguishing agent fromWhen the APU fire warning switch is rotated in either direction, the extinguishing agent from

the bottle is automatically expelled into the APU shroud. When this occurs, some of thethe bottle is automatically expelled into the APU shroud. When this occurs, some of the

pressure from the bottle is routed to the system discharge indicator (yellow disc). Thepressure from the bottle is routed to the system discharge indicator (yellow disc). The

pressure forces a small ³knockpressure forces a small ³knock--out´ pin to punch the yellow disc out onto the ground. Theout´ pin to punch the yellow disc out onto the ground. The

³knock³knock--out´ pin will protrude slightly from the hole where the yellow disc was.out´ pin will protrude slightly from the hole where the yellow disc was.






Slide 52 of 57

Main Gear Wheel Well Fire DetectionMain Gear Wheel Well Fire Detection

When the temperature of the sensing element rises to a preWhen the temperature of the sensing element rises to a pre--determined limit, the WHEELdetermined limit, the WHEEL

WELL fire warning light illuminates and the fire warning bell sounds. These picturesWELL fire warning light illuminates and the fire warning bell sounds. These pictures

indicate which lights will be illuminated during a wheel well fire condition.indicate which lights will be illuminated during a wheel well fire condition.

The WHEEL WELL fire warning light will remain illuminated until the temperature of the fireThe WHEEL WELL fire warning light will remain illuminated until the temperature of the fire

detector loop drops below the predetector loop drops below the pre--determined limit.determined limit.

Note: The main gear wheel well detection system does not incorporate any type of fireNote: The main gear wheel well detection system does not incorporate any type of fire

extinguishing system.extinguishing system.




Slide 53 of 57

FAULT/INOP TestFAULT/INOP Test

The fault detection circuits for both engines and the APU are tested by pushing and holding the TESTThe fault detection circuits for both engines and the APU are tested by pushing and holding the TEST

switch to the FAULT/INOP position. The picture above and the list below indicates which lights will beswitch to the FAULT/INOP position. The picture above and the list below indicates which lights will be

illuminated during ailluminated during a succ essful succ essful FAULT/INOP test:FAULT/INOP test:

The FAULT light illuminates.The FAULT light illuminates. The APU DET INOP light illuminates.The APU DET INOP light illuminates.

The OVHT/DET system annunciator light illuminatesThe OVHT/DET system annunciator light illuminates (due to the illumination of the APU DET INOP light)(due to the illumination of the APU DET INOP light)..

Both MASTER CAUTION lights illuminate.Both MASTER CAUTION lights illuminate.




Slide 54 of 57

FAULT/INOP TestFAULT/INOP Test

When the FAULT/INOP test switch is released, the FAULT and APU DET INOP lights extinguish. TheWhen the FAULT/INOP test switch is released, the FAULT and APU DET INOP lights extinguish. The

MASTER CAUTION and OVHT/DET system annunciator lights extinguish when either MASTERMASTER CAUTION and OVHT/DET system annunciator lights extinguish when either MASTER

CAUTION light is pressed.CAUTION light is pressed.

If the FAULT or APU DET INOP lights do not illuminate during the test, the respective fault detectionIf the FAULT or APU DET INOP lights do not illuminate during the test, the respective fault detection

circuits are inoperative and the FAULT/INOP test would therefore be consideredcircuits are inoperative and the FAULT/INOP test would therefore be considered unsucc essful.unsucc essful.




Slide 55 of 57

OVHT/FIRE TestOVHT/FIRE Test

To test the overheat/fire detection loops on both engines, the APU fire detector loop, and the main gear To test the overheat/fire detection loops on both engines, the APU fire detector loop, and the main gear

wheel well fire detector loop, position the TEST switch to the OVHT/FIRE position. The picture abovewheel well fire detector loop, position the TEST switch to the OVHT/FIRE position. The picture above

and the list below indicates which lights will be illuminated during aand the list below indicates which lights will be illuminated during a succ essful succ essful OVHT/FIRE test:OVHT/FIRE test:

The fire warning bell sounds.The fire warning bell sounds.

Both engine fire warning switches illuminate.Both engine fire warning switches illuminate.

The APU fire warning switch illuminates.The APU fire warning switch illuminates.

Both ENG OVERHEAT lights illuminate.Both ENG OVERHEAT lights illuminate.

Both MASTER CAUTION lights and both FIRE WARN lights illuminate.Both MASTER CAUTION lights and both FIRE WARN lights illuminate.

The OVHT/DET system annunciator light illuminatesThe OVHT/DET system annunciator light illuminates (due to the illumination of the ENG OVERHEAT lights)(due to the illumination of the ENG OVERHEAT lights)..

The WHEEL WELL fire warning light illuminatesThe WHEEL WELL fire warning light illuminates (if AC power is on the aircraft)(if AC power is on the aircraft)..

The APU fire warning light flashes and the APU fire warning horn soundsThe APU fire warning light flashes and the APU fire warning horn sounds (if on the ground)(if on the ground)..




Slide 56 of 57


When the OVHT/FIRE test switch is released, the fire warning bell silences and all overheat andWhen the OVHT/FIRE test switch is released, the fire warning bell silences and all overheat and

fire warning lights extinguish. The MASTER CAUTION and OVHT/DET system annunciator fire warning lights extinguish. The MASTER CAUTION and OVHT/DET system annunciator

lights extinguish when either MASTER CAUTION light is pressed.lights extinguish when either MASTER CAUTION light is pressed.




Slide 57 of 57


During aDuring a succ essful succ essful OVHT/FIRE test, the FAULT lightOVHT/FIRE test, the FAULT light will notwill not illuminate along with the other overheat andilluminate along with the other overheat and

fire warning lights. If the FAULT light does illuminate during the OVHT/FIRE test, this indicates that one or fire warning lights. If the FAULT light does illuminate during the OVHT/FIRE test, this indicates that one or

more detector loops have failed on either engine. The OVHT/FIRE test would therefore be consideredmore detector loops have failed on either engine. The OVHT/FIRE test would therefore be considered

unsucc essful.unsucc essful. In order to determine which loops on which engine have failed, the OVHT/FIRE test mustIn order to determine which loops on which engine have failed, the OVHT/FIRE test mustbe performed again while each OVHT DET switch is positioned to ³A´ and then ³B´. For example, let¶sbe performed again while each OVHT DET switch is positioned to ³A´ and then ³B´. For example, let¶s

assume that loop ³A´ is inoperative on the No. 1 engine. When the OVHT/FIRE test is performed with bothassume that loop ³A´ is inoperative on the No. 1 engine. When the OVHT/FIRE test is performed with both

OVHT DET switches in ³A,´ all overheat and fire warning lights illuminate normallyOVHT DET switches in ³A,´ all overheat and fire warning lights illuminate normally exceptexcept for thefor the

ENG 1 OVERHEAT and the No. 1 fire warning switch. The FAULT light also illuminates reaffirming that aENG 1 OVERHEAT and the No. 1 fire warning switch. The FAULT light also illuminates reaffirming that a

fault condition exists on the ³A´ loop, No. 1 engine. The picture above indicates which lights will befault condition exists on the ³A´ loop, No. 1 engine. The picture above indicates which lights will be

illuminated/extinguished during an OVHT/FIRE test with an inoperative ³A´ loop, No. 1 engine. Notice theilluminated/extinguished during an OVHT/FIRE test with an inoperative ³A´ loop, No. 1 engine. Notice the

ENG 2 OVERHEAT and No. 2 fire warning switch are illuminated indicating loop ³A´ No. 2 engine is good.ENG 2 OVERHEAT and No. 2 fire warning switch are illuminated indicating loop ³A´ No. 2 engine is good.



Extinguisher TestExtinguisher Test

When the extinguisher test switch is positioned to 1 or 2, circuit continuity is tested from the engine andWhen the extinguisher test switch is positioned to 1 or 2, circuit continuity is tested from the engine and

APU fire extinguisher bottle squibs to the respective fire warning switch.APU fire extinguisher bottle squibs to the respective fire warning switch.

All three green extinguisher test lights will illuminate indicating aAll three green extinguisher test lights will illuminate indicating a succ essful succ essful test.test.

The following is what occurs when the extinguisher test switch is positioned to 1 and 2:The following is what occurs when the extinguisher test switch is positioned to 1 and 2:Positioned to 1Positioned to 1 ± ±

Circuit continuity is tested on the No. 1 squib for both the left and right fire extinguisher bottles. CircuitCircuit continuity is tested on the No. 1 squib for both the left and right fire extinguisher bottles. Circuit

continuity is also tested for the squib on the APU fire extinguisher bottle.continuity is also tested for the squib on the APU fire extinguisher bottle.

Positioned to 2:Positioned to 2:

Circuit continuity is tested on the No. 2 squib for both the left and right fire extinguisher bottles. CircuitCircuit continuity is tested on the No. 2 squib for both the left and right fire extinguisher bottles. Circuit

continuity is testedcontinuity is tested againagain for the squib on the APU fire extinguisher bottle.for the squib on the APU fire extinguisher bottle.

Documents

Fire Protection R 01