Cargo Smoke Detector system

 

The smoke detectors in the lower cargo compartments are monitored by the cargo electronic units (CEUs). These units process inputs from smoke detectors and interface with the components in the flight compartment.   

   If smoke is detected in the lower cargo compartment, the detector sends an alarm signal to the CEU. The CEU sends the alarm signal to the cargo fire control panel.   

   The cargo fire control panel turns on the FWD or AFT red fire lights and sends an alarm signal to these components:   

   Cabin pressure control system    

   P7 FIRE WARN lights come on    

   Aural warning unit gives the bell sound.    

   The cargo fire control panel sends the alarm signal to the cabin pressure control system. This signal causes the CPC to set the cabin pressure rate of descent to 750 slfpm. This helps prevent smoke penetration into the passenger cabin from the lower lobe. This function is inhibited on the ground.