Smoke Detection Flashcards
Areas that must have smoke detectors
Galleys/Toilets and inaccessible compartments
Optical Smoke Detector
Smoke present light is reflected off particles and detected by sensory
Two or more detectors will trigger an alarm
Ionising Smoke Detection System
Material emit alpha particles
Small current flows between
Smoke absorbs particles and ionisation stops so current flow stops
Triggers warning
Where else are fire detection systems in AC?
Engines/APU/Cargo compartments
Fire Zones are
Areas of perceived risk of fire
Toilets/baggage holds/hydraulic bays
Engine Bay Fire Zone
Sprayed into all of the zone
Not automatically operated
APU Fire zone
Self contained/APU will shut down if fire detected
Continuous Loop Engine Fire Detection
Temperature rises the resistance in the salt goes down
Current increases/change in resistance
Signal fire
Continuous Loop Detection faults
AMBER fault caption in cockpit
Can be reset by turning off faulty loop
Gas filled detectors
Fire causes pressure to rise from 8psi to 40psi causing fire warning signal
Bimetalic overheat sensors
Used in critical spots on airframe
Differential expansion of metals to heat
Contact close which signal warning
Does have time delay to prevent false warnings due to vibrations
Fire warning indications on the flight deck
Illuminate red flashing fire master caution caption
Fire warning bell
Illuminate ENG 1/2 FIRE caption
Illuminate the appropriate extinguisher handle
Warning on EICAS or ECAM
What fire warnings can be cancelled?
Attention getters can be cancelled
Red fire captions remain illuminated until a fire is no longer detected
Pulling the fire handle will…
Close the wing spar valve isolating engine for fuel
Closes bleed air PRSOV
Shut off hydraulic pump
Isolates engine driven electrical generator
Arms the extinguisher squib
Closes the APU shut off valve
Arms the squib ready to be fired
Once fire handle is armed and pulled right or left…
Squib cartridge on extinguisher bottle fire and ruptures the retaining disc in the valve
