737 Fire Protection

Question 1

Which areas of the aircraft have Fire Detection systems?

Answer 1

Engines, APU, Main Wheel Well, Lower Cargo Compartment

Question 2

Which areas have fire Extinguishing/Suppression systems?

Answer 2

Engine, APU, Lower cargo compartment

Question 3

Which areas have both fire detection and fire extinguishing/suppression

Answer 3

All but Main Wheel Well

Question 4

What does an illuminated Master FIRE WARN (red) light indicate? What causes it to illuminate?

Answer 4

FIRE or TEST

Extinguished by pushing light or using BELL CUTOUT switch

Question 5

What causes the Fire Warning Bell to sound?

Answer 5

Comes on in conjunction with the FIRE WARN light (test or actual fire detected)

Question 6

How can the Fire Warning Bell be silenced?

Answer 6

Pushing either FIRE WARN lights or the BELL CUTOUT.

Question 7

What does an illuminated Engine Overheat (amber) light indicate?

Answer 7

an overheat condition

Question 8

What causes the Engine Overheat (amber) light to illuminate?

Answer 8

The temperature of a detector has increased to a predetermined limit

Question 9

What causes the Engine Overheat (amber) light to extinguish?

Answer 9

Temperature drops below the predetermined limit - COOLS OFF

Question 10

How many engine fire extinguisher bottles are there?

Answer 10

2 total

Question 11

Can these bottles be discharged into both engines, or only the respective engine?

Answer 11

2 bottles total - 2 OR 1 discharges into one engine

Question 12

What powers the Engine Overheat and Fire Detection system?

Answer 12

Detection = BAT BUS

Question 13

The Engine Fire Extinguishing system power source?

Answer 13

Extinguish = HOT battery bus

Question 14

What does pulling the engine fire switch do?

Answer 14

Lighter colors panels on overhead Just think ISOLATE & VENTILATE and affects those panels
B - Bleed valve closes
R - Reverser disabled
G - Generator tripped
H - Hydraulic valve closes
F - Fuel valves close (engine fuel valve & spar valve)
S - Squibs & Switch (squib armed & switch able to be turned)

Question 15

What does rotating the engine fire switch do?

Answer 15

Electronically “fires” a squib, discharging the extinguishing agent into the related engine. Rotating the switch the other way discharges the remaining bottle.

Question 16

How many detector loops does each engine have?

Answer 16

2 loops

Question 17

What do the loops provide?

Answer 17

Fire and overheat detection

Question 18

What are the indications of a single loop failure?

Answer 18

No flight deck indication of a single loop failure

Question 19

A dual loop failure?

Answer 19

FAULT light (with OVHT DET switch in NORMAL)

Question 20

What does an illuminated FAULT (amber) light indicate?

Answer 20

Dual loop failure (with OVHT DET switch in NORMAL)

A or B loop failure (with switch in associated position)

Question 21

What causes FAULT (amber) light to illuminate?

Answer 21

The fault detection loops detects a fault

Question 22

What causes FAULT (amber) light to Extinguish?

Answer 22

Doesn’t extinguish

Question 23

What does an illuminated Engine Fire (red) Switch indicate?

Answer 23

A fire (or a test) handle is unlocked when lit

Question 24

What are indications of an engine fire?

Answer 24

Fire Warning Bell
Both master FIRE WARN lights illuminate
Related engine fire switch illuminates *related engine overheat alert indications likely illuminate

Question 25

What are the components of the APU Fire Extinguishing system?

Answer 25

APU Fire switch
Single APU Fire bottle
APU bottle discharge light

Question 26

How many fire extinguisher bottles does the APU fire extinguishing system have?

Answer 26

ONE

Question 27

What does pulling the APU Fire (red) switch up do?

Answer 27

GBFISH 
G - generator tripped 
B - bleed valve closed 
F - fuel deactivated 
I - inlet door closed 
S - squib armed 
H - handle unlocked 
*auto shutdown should have occurred, but this will happen anyways if you pull the handle up*

Question 28

rotating the APU Fire switch?

Answer 28

Fires the APU squib into the APU

Question 29

Where is the APU Fire Protection Panel located, and what does it do?

Answer 29

RIGHT main wheel well. Same stuff as in the flight deck.

Question 30

What powers the APU Fire Detection system?

Answer 30

Battery Bus

Question 31

The APU Fire Extinguishing system?

Answer 31

Hot battery bus

Question 32

What are the components of the Main Wheel Well Fire Protection system?

Answer 32

Fire detection (only) and a single fire loop in the wheel well

Question 33

What does an illuminated WHEEL WELL (red) light indicate?

Answer 33

Indicates temp has exceeded predetermined limit

Question 34

What causes the WHEEL WELL (red) light to illuminate?

Answer 34

Temperature sensed above predetermined limit

Question 35

What causes the WHEEL WELL (red) light to Extinguish?

Answer 35

Temperature decreases below onset temp

Question 36

What are the components of the Lower Cargo Fire Protection system?

Answer 36

Smoke detectors 2 fire extinguisher bottles - First bottle discharges for 60 min - Second bottle discharges for 135 additional min to maintain the level of halon in the compartment

Question 37

What does an illuminated DETECTOR FAULT (amber) light indicate?

Answer 37

FAULT in one or more of the detectors

Question 38

An illuminated Cargo Fire FWD/AFT (red) light?

Answer 38

One detector in each loop has detected smoke (they agree)

Question 39

The FAULT/INOP and OVHT/FIRE TEST switch, when in the FAULT/INOP position, tests what?

Answer 39

Testing the fault detection circuitry

Question 40

When in the OVHT/FIRE position? Testing what?

Answer 40

Testing the fire detection circuitry