A CANADAIR CL65 DURING PUSHBACK HAD MASTER CAUTION AND 'SMOKE CARGO' MSG. VISUAL CHK BY PUSHBACK CREW REVEALED A FALSE WARNING.

Narrative

DURING PUSH BACK FROM GATE X-Y ZZZ. WE HAD A SMOKE CARGO INDICATION. THE CAPT SHUT DOWN THE #1 ENG AND WE COMPLETED THE SMOKE CARGO CHKLIST SHORT OF DISCHARGING THE BOTTLES. CAPT WAS STILL IN CONTACT WITH GND PERSONNEL AND HAD THEM OPEN AND CONFIRM NO FIRE OR SMOKE IN THE CARGO COMPARTMENT. THE NUMBER TWO ENG WAS SHUT DOWN AND THE ACFT WAS TOWED BACK TO THE GATE. PAXS WERE DEPLANED THRU NORMAL EXIT AND MAINT WAS CALLED. WE ELECTED NOT TO DISCHARGE THE BOTTLES OR EVACUATE THE PAXS. IT WAS A FAULTY MSG. THIS HAS OCCURRED NUMEROUS TIMES THROUGHOUT OUR FLEET AND NEEDS TO BE CORRECTED BY THE MAKER. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE PROB WAS A FALSE WARNING CAUSED BY A FAULTY SENSOR. THE RPTR CLAIMS THE MASTER CAUTION AND 'SMOKE CARGO' MSG ARE A RECURRING PROB CAUSED BY FAULTY SENSORS. THE RPTR STATED THE AIRPLANE WAS STILL CONNECTED TO THE TUG AND AFTER MAINT INSPECTION AND NO SMOKE DISCOVERED THEY WERE TOWED TO THE GATE AND DEPLANED THE PAXS. CALLBACK FROM ACN 492256: THE RPTR STATED THE PROB WAS CAUSED BY A FAULTY OR DIRTY SMOKE SENSOR. THE RPTR CLAIMS MAINT MADE A STUDY OF THE SENSORS AND FOUND THE SENSORS MAINLY FAILED BTWN 3000 HRS AND 4000 HRS WITH THE LIFE CYCLE OF THE SENSORS BEING 5000 HRS.