Fire Protection

Question 1

(ALL) Indications of an engine fire warning (MD-88 & MD90):

Answer 1

• Fire bell then vocal warning “FIRE, LEFT/RIGHT ENGINE”.
• Illuminated L/R ENG FIRE handle.

MD-88 only:
• L/R LOOP A and LOOP B lights.
• FIRE DETECTOR LOOP message.
• Both MASTER CAUTION lights.

MD-90 only;
• Illumination of respective FUEL SWITCH (if ON).

Question 2

(88, 90) Function of the AGENT LOW Light (amber):

Answer 2

• Illuminated - Respective fire extinguishing agent has been discharged (pressure low).

Question 3

(88, 90, 9) How is cargo fire suppression accomplished?

Answer 3

• Two fire bottles (separate from engine/APU fire bottles).
• Bottle #1: a high rate discharge bottle, used to rapidly flood affected cargo compartment with halon and smother fire.
• Bottle #2: low rate discharge bottle that slowly releases halon into the cargo compartment, extending fire suppression effectiveness.

Question 4

(88, 90) Indications of a cargo fire warning

Answer 4

• Red CARGO FIRE light on OAP.
• MASTER WARNING lights on the glareshield.
• High pitched tone from aural alerter which can be silenced by pushing FIRE BELL OFF button between engine fire handles.
• FIRE light on cargo fire control panel from alarming compartment.
• ARMED light of the alarming compartment with BTL 1 DISCH light to indicate automatic suppression system arming has occurred.

Question 5

(88, 90) Cockpit indications of an APU Fire warning:

Answer 5

• Aural/vocal warning “APU FIRE” (3 cycles).
• Horns (cockpit [3 cycles] and external [continuous]).
• APU FIRE lights (cockpit and external).
• Both MASTER WARNING lights.

MD-88 only:
• APU LOOP A and B.
• FIRE DETECTOR LOOP message.
• Both MASTER CAUTION lights.

NOTE: With APU master switch in the OFF position, all APU aural warnings are inhibited.

Question 6

(88, 90) Function of Cargo Fire Detection system:

Answer 6

• Dual loop system in each smoke detector unit.
• Each unit incorporates 2 smoke detectors and 2 heat sensors.
• 1 smoke detector and 1 heat sensor make up 1 loop.
• Cargo fire warning will activate if selected loop(s) detect smoke and/or heat.

Question 7

(88, 90) How are Engine and APU fire suppression accomplished?

Answer 7

• Use of two fire bottles.

* Each bottle has separate discharge heads and distribution lines to each engine and APU.

Question 8

(88, 90) Function of APU FIRE CONT Switch:

Answer 8

• NORM - Normal position.

* OFF & AGENT ARM - Immediately shuts down APU and arms fire extinguishers.

Question 9

(88, 90) Function of ENG FIRE Handle (red):

Answer 9

Light Illuminated - Associated engine fire is detected or system fire test is in progress.

Pull - (Fully extended position)
• Silences the aural warning, shuts off associated engine fuel (valve at wing spar), hydraulic and pneumatic systems, and trips generator.
• MD-90 only: Shuts off fuel at the fuel metering unit and as well as the wing spar.
Rotate - (With additional pulling) Discharges respective fire extinguishing agent into engine cowling.

Question 10

(88, 90) Difference and reason for difference in cargo fire discharge rates:

Answer 10

• Bottle #1 is a high rate discharge bottle that is used to rapidly flood the affected cargo compartment with halon and smother the fire.
• Bottle #2 is a low rate discharge bottle that slowly releases halon into the cargo compartment, extending fire suppression effectiveness.

NOTE: Bottle #2 will not automatically discharge if landing has occurred.

NOTE: #1 bottle should always be discharged first to achieve the maximum fire knockdown. #2 bottle should be discharged 15 min later. Due to discharge rate differences, firing both fire bottles at the same time will DECREASE fire suppression capability

Question 11

(88, 90) How long cargo fire bottles provide fire suppression?

Answer 11

• 2 bottles working together give flight crew approx 60 min of fire suppression