Narrative:

We arrived in ZZZ and needed the crew oxygen svced. I performed a postflt of the aircraft and found no abnormalities. The mechanic svced the oxygen and signed off the aircraft. I performed a preflight when the mechanic was finished in accordance with my airline's fom. Again, I observed no abnormalities. On takeoff from ZZZ, we observed a slight 'whistling' noise coming from the first officer's (my side) side of the aircraft. This was followed or accompanied rather (it happened quickly) by a master caution message for a 'stall failure.' as airspeed increased, the noise increased. We realized that the crew oxygen service door was either unlocked or open and was causing erroneous information for the 32 angle of attack vane (first officer side behind oxygen door). We ran the appropriate checklists and returned for a landing 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 preflight after the mechanic finished. However, I cannot be positive that it was secured properly. My airline has directed flight crews to 'look' but not 'touch' this door due to this exact situation happening before.

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Original NASA ASRS Text

Title: 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.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.