Narrative:

An area of precipitation was approaching the airport when aircraft X was cleared for takeoff. The amass system was not in limited mode; when rain started falling onto runway 17L and the departure end; it set off the amass system which issued a 'warning runway 17L departure; runway occupied.' the runway was not occupied with anything but rain. Abort was issued to aircraft X as required; resulting in a maintenance delay and refueling delay. This piece of equipment (amass) issues many false alerts during raining conditions and we are advised to go to 'limited' mode when it's raining. However; in this instance just a small amount of rain started when the aircraft started his departure roll.

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Original NASA ASRS Text

Title: RAIN BEGAN TO FALL ON RWY 17L AT SDF AS AN RJ700 WAS ON DEP ROLL. THE RAIN TRIGGERED AN AMASS ALARM; WHICH REQUIRES THE CTLR TO ISSUE A TKOF ABORT.

Narrative: AN AREA OF PRECIP WAS APCHING THE ARPT WHEN ACFT X WAS CLRED FOR TKOF. THE AMASS SYS WAS NOT IN LIMITED MODE; WHEN RAIN STARTED FALLING ONTO RWY 17L AND THE DEP END; IT SET OFF THE AMASS SYS WHICH ISSUED A 'WARNING RWY 17L DEP; RWY OCCUPIED.' THE RWY WAS NOT OCCUPIED WITH ANYTHING BUT RAIN. ABORT WAS ISSUED TO ACFT X AS REQUIRED; RESULTING IN A MAINT DELAY AND REFUELING DELAY. THIS PIECE OF EQUIP (AMASS) ISSUES MANY FALSE ALERTS DURING RAINING CONDITIONS AND WE ARE ADVISED TO GO TO 'LIMITED' MODE WHEN IT'S RAINING. HOWEVER; IN THIS INSTANCE JUST A SMALL AMOUNT OF RAIN STARTED WHEN THE ACFT STARTED HIS DEP ROLL.

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.