Fire Protection

Question 1

Explain the indications of an engine overheat

Answer 1

• Both MASTER CAUTION lights illuminate
• The OVHT/DET (amber) system annunciation light illuminates
• The related ENG OVERHEAT (amber) light illuminates

Question 2

Explain the function of the Engine Fire Warning switch

Answer 2

In - normal position, mechanically locked if no fire signal

Fire:
- Master FIRE WARN lights illuminate and fire warning bell sounds
- Related engine fire warning switch illuminated (red):
- indicates fire in related engine
- unlocks related engine fire warning switch

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

In - normal position, mechanically locked if no fire signal

Fire:
- Master FIRE WARN lights illuminate, fire warning bell sounds
APU fire warning switch illuminated (red):
- indicates fire in APU
- unlocks APU fire warning switch

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 (amber) 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 the engine has failed

NOTE: MASTER CAUTION and OVHT/DET system annunciation 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 OVT/DET system annunciation 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 DET 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

• 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

• The fire warning bell sounds
• Both master FIRE WARN lights illuminate
• The APU fire switch illuminates
• The APU automatically shuts down (all related APU FAULT light indications illuminate)
• The wheel well APU fire warning horn sounds (on the ground only), and the wheel well APU fire warning light flashes

Question 10

Recall the indications of a Cargo Fire Warning

Answer 10

• The fire warning bell sounds
• Both master FIRE WARN lights illuminate
• The FWD/AFT cargo fire warning light(s) illuminate(s)

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 system

Answer 12

Engine: 2 extinguishing bottles
APU: 1 extinguishing bottle
Cargo: 1 extinguishing bottle