Chapter 8: Fire Protection

Question 1

Explain the indications of an engine overheat.

Answer 1

• The related ENG OVERHEAT light illuminates.
• The OVHT/DET system annunciator light illuminates.
• Both MASTER CAUTION lights illuminate.

Question 2

Explain the function of the Engine Fire Warning switch.

Answer 2

Illuminated (red) –

• indicates fire in related engine.
• unlocks related engine fire warning switch.
• Master FIRE WARN lights illuminate and fire warning bell sounds.

In – normal position, mechanically locked if no fire signal.

Up –

• arms one discharge squib on each engine fire extinguisher.
• allows engine fire warning switch to rotate.

Rotate (left or right) – discharges related fire bottle.

Question 3

Explain the function of the APU Fire warning switch.

Answer 3

Illuminated (red) –

• indicates fire in APU.
• unlocks APU fire warning switch.
• Master FIRE WARN lights illuminate, fire warning bell sounds.

In – normal position, mechanically locked if no fire signal.

Up –

• arms APU extinguisher circuit.
• allows APU fire warning switch to rotate.

Rotate (left or right) – discharges APU fire bottle.

Question 4

Explain the meaning of the FAULT light on the Overheat/Fire Protection panel.

Answer 4

With the OVHT DET switch in NORMAL – The FAULT light indicates both detector loops for an engine have failed.

If one loop fails with the OVHT DET switch in NORMAL, that loop is automatically deselected and the remaining loop functions as a single loop detector. There is no flight deck indication of single loop failure.

With the overheat detector switch in A or B – the FAULT light indicates the selected loop for that engine has failed.

Note: MASTER CAUTION and OVHT/DET system annunciator lights do not illuminate for a FAULT light.

Question 5

Explain the meaning of the APU DET INOP light.

Answer 5

Indicates the APU detector loop has failed.

MASTER CAUTION and OVHT/DET system annunciator lights illuminate.

Question 6

Explain the meaning of an illuminated DETECTOR FAULT light on the Cargo Fire panel.

Answer 6

One or more of the selected detector loop(s) in either cargo compartment has failed.

Question 7

Explain the function of the Detector Select (DET SELECT) switches on the Cargo Fire panel.

Answer 7

NORM - detection loop A and B are active.
A - detection loop A is active.
B - detection loop B is active.

Note: The system can be manually converted to single-loop detection through the DETECT SELECT switch on the cargo fire control panel. In the event of a power failure in one loop the system automatically converts to single-loop detection.

Question 8

Recall the indications of an engine fire warning.

Answer 8

Engine Fire:

• the related engine fire warning switch illuminates.
• both master FIRE WARN lights illuminate.
• the fire warning bell sounds.
• all related engine overheat alert indications illuminate.

Question 9

Recall the indications of an APU fire warning.

Answer 9

APU Fire:

• the fire warning bell sounds.
• both master FIRE WARN lights illuminate
• the APU fire switch illuminates.
• .the APU automatically shuts down
• the wheel well APU fire warning horn sounds (on the ground only), and the wheel well APU fire warning light flashes.

Note: The APU automatically shuts down (all related APU FAULT light indications illuminate)

Question 10

Recall the indications of a Cargo Fire Warning.

Answer 10

Cargo Fire

• the Fire Warning Bell sounds.
• both Master FIRE WARN lights illuminate.
• the FWD/AFT Cargo Fire Warning light(s) illuminates.

Question 11

Explain the meaning of an illuminated Fire Bottle Discharge light

Answer 11

Indicates related fire extinguisher bottle has discharged.

Question 12

Recall the number of fire extinguishing bottles available for Engine, APU and the Cargo Compartment extinguishing systems.

Answer 12

Engine – 2 extinguishing bottles

APU – 1 extinguishing bottle

Cargo – 1 extinguishing bottle