A320 Engine and APU Fire Panel is part of OVH overhead panel
Engine Fire Switch #
ENGINE FIRE WARNING INDICATIONS – An engine fire is indicated by an aural CRC, the illumination of the engine’s FIRE light on the Engine Fire panel, illumination of the engine’s FIRE switch on the Engine Start and Ignition Panel, illumination of the MASTER WARNING lights, and by an ECAM warning.
ENGINE FIRE WARNING CONDITIONS – An engine fire warning appears under the following conditions:
- Both loops detect a fire
- One loop detects a fire when the other loop is faulty
- A break in both loops occurs within 5 seconds of each other
- A fire test is performed
LOOP FAULTS – Loop faults cautions appear on the the E/WD; if one loop has a fault, if two loops have faults, or if the fire detection unit fails.
ENGINE FIRE SWITCH (guarded) – When the ENG FIRE Switch is released out, an electrical signal:
- Silences the aural warning
- Arms the squibs (Squib light illuminates)
- Deactivates the Integrated Drive Generator (IDG)
- Cuts off the FADEC power supply
- Closes the fuel LP valve
- Closes the hydraulic fire shutoff valve
- Closes the engine bleed valve
- Closes the pack flow control valve
Engine Agent Switch #
SQUIB – The engine’s AGENT switches are active when a corresponding engine FIRE switch is released out. The SQUIB lights illuminate white to facilitate identification of the agent switch(es) that are active.
DISCH – When the engine’s AGENT switch is active and pushed momentarily, the fire extinguisher bottle is discharged. The DISCH light illuminates amber when the fire extinguisher bottle agent pressure is low.
FIRE PROTECTION – Each engine is provided with two fire extinguishers with electrically operated squibs to discharge their contents. Each squib has a dual electric supply. An AGENT switch for each fire extinguisher bottle is located on the respective ENG FIRE panel that enables discharging of the fire extinguisher’s agent.
Engine Test Button #
TEST – The Engine’s TEST Button permits testing of the engine’s fire detection and extinguishing system operation. When the TEST Button is pressed it:
- Activates an ECAM ENG FIRE warning on the Engine Warning Display
- Activates the Continuous Repetitive Chime
- Illuminates two flashing MASTER WARNING lights
- Illuminates the associated ENG FIRE switch
- Illuminates the SQUIB lights (if discharge supplies are available)
- Illuminates the DISCH lights
- Illuminates the FIRE light on engine start and ignition panel
FIRE DETECTION –
Each engine is equipped with a fire and overheat detection system consisting of two identical loops (A and B) mounted in parallel. Each detection loop consists of three sensing elements located in the pylon nacelle, engine core, and engine fan section. When a sensing element detects an overheat, a signal is transmitted to a fire detection unit. If a fault or break occurs in one loop, the fire warning system is not affected; fire detection is provided by the unaffected loop.
APU Fire Switch #
APU FIRE WARNING INDICATIONS – An APU fire is indicated by an aural CRC, the illumination of the APU FIRE switch and MASTER WARNING lights, and by an ECAM warning on the E/WD.
APU FIRE WARNING – An APU fire warning appears under the following conditions:
- Both loops detect a fire
- One loop detects a fire when the other loop is faulty
- A break in both loops occurs within 5 seconds of each other
- When a fire test is performed
APU FIRE SWITCH (guarded) – The APU Fire Switch is normally IN and Guarded. When the APU ENG FIRE Switch is released OUT, an electrical signal:
- Silences the aural warning
- Arms the squib (Squib light illuminates)
- Deactivates the APU Generator
- APU shuts down
- APU fuel pump is turned off
- APU bleed and cross bleed valves are closed
APU Agent Switch #
SQUIB – The APU AGENT switch is active when a corresponding APU FIRE switch is released out. The SQUIB light illuminates white to indicate that the agent switch is active.
DISCH – When the APU’s AGENT switch is active and pushed momentarily, the fire extinguisher bottle is discharged. The DISCH light illuminates amber when the fire extinguisher bottle agent pressure is low.
FIRE PROTECTION – A single fire extinguisher bottle is provided for the APU. If an APU fire is detected on the ground, the APU automatically shuts down and the extinguishing agent is automatically discharged (3 seconds after fire warning is activated).
If an APU fire is detected in flight, the APU must be manually shut down, and the agent manually discharged.
