Narrative:

Normal procedure on takeoff at our company is for the PNF to call '100 KTS' on the airspeed to verify operation. During this takeoff, I, as PF, noticed I was indicating a little more than 100 KTS without hearing the call. I called '100 KTS' and the first officer said 'I don't have 100 KTS.' I had an amber airspeed miscomparitor icon displayed but we got no caution message (these are inhibited during takeoff) or chime. While I was chewing on these events for about 2 seconds, the first officer called 'abort.' I aborted the takeoff well below V1 and we pulled off the runway and called maintenance. They thought this was perhaps a momentary glitch and suggested we attempt another takeoff. (We told them we had about a 20 KT discrepancy in the #1 and #2 airspeed indicators with the left one indicating higher.) a second attempt produced the same result. This time we checked the standby airspeed and it seemed to agree with the left one. Upon returning to the gate we discovered that the oxygen service access door was not latched. This is located in front off the right pitot tube. The door was stowed and subsequent takeoff was normal. Callback conversation with reporter revealed the following information: reporter states the aircraft was a canadair rj and this was the reporter's first experience of the open oxygen door causing airspeed problems. The reporter states a small door located below the oxygen service door is used after the push back operation to remove the nose gear down lock pin. The oxygen service door is not visible from the first officer's side window. Callback conversation with reporter acn 380406 revealed the following information: reporter states the door was not open during when the preflight walkaround check was accomplished. The reporter said this was a first time experience of the oxygen door causing airspeed problems but does know it has happened before.

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Original NASA ASRS Text

Title: A CANADAIR RJ REJECTED TKOF TWICE DUE TO FO'S AIRSPD INDICATING 20 KTS LOW CAUSED BY THE OXYGEN SVC DOOR LEFT OPEN.

Narrative: NORMAL PROC ON TKOF AT OUR COMPANY IS FOR THE PNF TO CALL '100 KTS' ON THE AIRSPD TO VERIFY OP. DURING THIS TKOF, I, AS PF, NOTICED I WAS INDICATING A LITTLE MORE THAN 100 KTS WITHOUT HEARING THE CALL. I CALLED '100 KTS' AND THE FO SAID 'I DON'T HAVE 100 KTS.' I HAD AN AMBER AIRSPD MISCOMPARITOR ICON DISPLAYED BUT WE GOT NO CAUTION MESSAGE (THESE ARE INHIBITED DURING TKOF) OR CHIME. WHILE I WAS CHEWING ON THESE EVENTS FOR ABOUT 2 SECONDS, THE FO CALLED 'ABORT.' I ABORTED THE TKOF WELL BELOW V1 AND WE PULLED OFF THE RWY AND CALLED MAINT. THEY THOUGHT THIS WAS PERHAPS A MOMENTARY GLITCH AND SUGGESTED WE ATTEMPT ANOTHER TKOF. (WE TOLD THEM WE HAD ABOUT A 20 KT DISCREPANCY IN THE #1 AND #2 AIRSPD INDICATORS WITH THE L ONE INDICATING HIGHER.) A SECOND ATTEMPT PRODUCED THE SAME RESULT. THIS TIME WE CHKED THE STANDBY AIRSPD AND IT SEEMED TO AGREE WITH THE L ONE. UPON RETURNING TO THE GATE WE DISCOVERED THAT THE OXYGEN SVC ACCESS DOOR WAS NOT LATCHED. THIS IS LOCATED IN FRONT OFF THE R PITOT TUBE. THE DOOR WAS STOWED AND SUBSEQUENT TKOF WAS NORMAL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THE ACFT WAS A CANADAIR RJ AND THIS WAS THE RPTR'S FIRST EXPERIENCE OF THE OPEN OXYGEN DOOR CAUSING AIRSPD PROBS. THE RPTR STATES A SMALL DOOR LOCATED BELOW THE OXYGEN SVC DOOR IS USED AFTER THE PUSH BACK OP TO REMOVE THE NOSE GEAR DOWN LOCK PIN. THE OXYGEN SVC DOOR IS NOT VISIBLE FROM THE FO'S SIDE WINDOW. CALLBACK CONVERSATION WITH RPTR ACN 380406 REVEALED THE FOLLOWING INFO: RPTR STATES THE DOOR WAS NOT OPEN DURING WHEN THE PREFLT WALKAROUND CHK WAS ACCOMPLISHED. THE RPTR SAID THIS WAS A FIRST TIME EXPERIENCE OF THE OXYGEN DOOR CAUSING AIRSPD PROBS BUT DOES KNOW IT HAS HAPPENED 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.