Fire & Overheat Protection

Question 1

FIDEX does what?

Answer 1

Controls and monitors all aspects of the fire protection system, and uses EICAS to alert the crew of smoke, overheat and fire conditions, or system faults.

Question 2

FIDEX is a dual ch. control unit, and each has its own source of power. What are those sources.

Answer 2

1. DC ESS BUS 1 & 2
2. The fire extinguishers are powered by BATT DIR BUS 1 & 2
   (makes sense because the airplane needs fire protection when there is no AC)

Question 3

When guarded L/R ENG FIRE switch/light is pressed. What occurs?

Answer 3

• Associated engine shuts down
• Four valves and a generator:
  1. Fuel supply is cut off
  2. Engine bleed air valves close
  3. Engine hydraulic shutoff valve closes
  4. VFG deactivates
  5. Fan air valve closes
• Both engine fire extinguisher bottles arm for discharge, indicated by the green AVAIL light illuminating on BTL 1 & BTL 2 switch/lights.

Question 4

When the guarded APU FIRE switch/light is pressed, what are the only two things to occur?

Answer 4

1. Fuel and bleed air are shutoff

2. VFG deactivates

Question 5

What happens if the system detects an APU fire on the ground?

Answer 5

APU auto-shutdown

Question 6

How many smoke detectors are located in the exhaust ducts of the forward and mid equipment bays?

Answer 6

Two

Question 7

What happens when one fire loop fails?

Answer 7

The second fire loops continues to provide overheat detection and a FIRE SYSTEM FAULT advisory message displays.