Narrative:

We had started our takeoff roll from ord runway 32L at intersection T10. After we entered the high speed regime; tower called and said in a very quiet; calm voice; without any urgency; that our takeoff clearance was canceled. The first officer immediately stated to tower that we were already rolling. Visibility was restr; and he wanted to clarify that tower did not think that we were in position and had not yet moved. Tower restated his prior transmission; again very calmly; and we aborted the takeoff at 120 KIAS/110 KT ground speed. After we completed the rejected takeoff and cleared the runway; tower informed us that they were getting a continuous 'amass collision system' alarm; which turned out to be due to a snow pile at the end of the runway. Their correct response to this alarm was to close that runway until the problem alarm could be addressed. We completed our checklist procedures in accordance with the airbus flight manual; and we returned to the gate for a maintenance inspection of the brakes and wheels; refueling; and re-deicing. We informed the passenger and spoke with our company to discuss the event and to confirm our release status. A false alarm that sounds continuously in the tower to erroneously alert them to an intruder on the runway can lead to complacency or to dangerous unneeded rejected takeoffs. In an area prone to winter WX and the snow piles resulting from clearing operations; why does the equipment detect and interpret a snow pile to be a vehicle or aircraft?

Related reports:

Google
 

Original NASA ASRS Text

Title: A320 CAPT DESCRIBED ATC DIRECTED ABORT AT ORD REPORTEDLY DUE TO CONTINUOUS AMASS ALARM.

Narrative: WE HAD STARTED OUR TKOF ROLL FROM ORD RWY 32L AT INTXN T10. AFTER WE ENTERED THE HIGH SPD REGIME; TWR CALLED AND SAID IN A VERY QUIET; CALM VOICE; WITHOUT ANY URGENCY; THAT OUR TKOF CLRNC WAS CANCELED. THE FO IMMEDIATELY STATED TO TWR THAT WE WERE ALREADY ROLLING. VISIBILITY WAS RESTR; AND HE WANTED TO CLARIFY THAT TWR DID NOT THINK THAT WE WERE IN POS AND HAD NOT YET MOVED. TWR RESTATED HIS PRIOR XMISSION; AGAIN VERY CALMLY; AND WE ABORTED THE TKOF AT 120 KIAS/110 KT GND SPD. AFTER WE COMPLETED THE REJECTED TKOF AND CLRED THE RWY; TWR INFORMED US THAT THEY WERE GETTING A CONTINUOUS 'AMASS COLLISION SYS' ALARM; WHICH TURNED OUT TO BE DUE TO A SNOW PILE AT THE END OF THE RWY. THEIR CORRECT RESPONSE TO THIS ALARM WAS TO CLOSE THAT RWY UNTIL THE PROB ALARM COULD BE ADDRESSED. WE COMPLETED OUR CHKLIST PROCS IN ACCORDANCE WITH THE AIRBUS FLT MANUAL; AND WE RETURNED TO THE GATE FOR A MAINT INSPECTION OF THE BRAKES AND WHEELS; REFUELING; AND RE-DEICING. WE INFORMED THE PAX AND SPOKE WITH OUR COMPANY TO DISCUSS THE EVENT AND TO CONFIRM OUR RELEASE STATUS. A FALSE ALARM THAT SOUNDS CONTINUOUSLY IN THE TWR TO ERRONEOUSLY ALERT THEM TO AN INTRUDER ON THE RWY CAN LEAD TO COMPLACENCY OR TO DANGEROUS UNNEEDED REJECTED TKOFS. IN AN AREA PRONE TO WINTER WX AND THE SNOW PILES RESULTING FROM CLRING OPS; WHY DOES THE EQUIP DETECT AND INTERPRET A SNOW PILE TO BE A VEHICLE OR ACFT?

Data retrieved from NASA's ASRS site as of January 2009 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.