A CANADAIR CL65 ON TKOF CLB AT 1000 FT EXPERIENCED A WHISTLING SOUND AND EICAS WARNING 'STALL FAILURE' CAUSED BY THE OXYGEN SVC DOOR OPEN. RETURNED TO FIELD.

Narrative

WE ARRIVED IN ZZZ AND NEEDED THE CREW OXYGEN SVCED. I PERFORMED A POSTFLT OF THE ACFT AND FOUND NO ABNORMALITIES. THE MECH SVCED THE OXYGEN AND SIGNED OFF THE ACFT. I PERFORMED A PREFLT WHEN THE MECH WAS FINISHED IN ACCORDANCE WITH MY AIRLINE'S FOM. AGAIN; I OBSERVED NO ABNORMALITIES. ON TKOF FROM ZZZ; WE OBSERVED A SLIGHT 'WHISTLING' NOISE COMING FROM THE FO'S (MY SIDE) SIDE OF THE ACFT. THIS WAS FOLLOWED OR ACCOMPANIED RATHER (IT HAPPENED QUICKLY) BY A MASTER CAUTION MESSAGE FOR A 'STALL FAILURE.' AS AIRSPD INCREASED; THE NOISE INCREASED. WE REALIZED THAT THE CREW OXYGEN SVC DOOR WAS EITHER UNLOCKED OR OPEN AND WAS CAUSING ERRONEOUS INFO FOR THE 32 ANGLE OF ATTACK VANE (FO SIDE BEHIND OXYGEN DOOR). WE RAN THE APPROPRIATE CHKLISTS AND RETURNED FOR A LNDG AT ZZZ WHICH WAS UNEVENTFUL AND ROUTINE. NO PRIORITY HANDLING BY ATC WAS RECEIVED OR REQUESTED. I BELIEVE THAT THE DOOR WAS CLOSED BUT NOT LATCHED ON PUSHBACK FROM THE GATE. THIS IS BECAUSE IT (DOOR) APPEARED CLOSED UPON MY PREFLT AFTER THE MECH FINISHED. HOWEVER; I CANNOT BE POSITIVE THAT IT WAS SECURED PROPERLY. MY AIRLINE HAS DIRECTED FLT CREWS TO 'LOOK' BUT NOT 'TOUCH' THIS DOOR DUE TO THIS EXACT SIT HAPPENING BEFORE.