Narrative:

Aircraft arrived lnk as flight XXXX with thin layer mixed ice covered with impact snow on leading edge surfaces. Deiced per fopm mandated deicing procedures. Crew complied with all fopm deicing and anti-icing procedures including a second visual inspection, pre-takeoff contamination check of both wings. Necessitated by decreased visibility value received from tower reduced holdover time to a range of 9- 12 mins. Neither wing had any visible signs of contamination. During takeoff roll between first officer's callouts of V1 and vr cockpit aural stall warning horn began sounding continuously. Continued sounding through rotation and gear retraction without interruption, changes in tone, or volume. Aural warning ceased a few seconds after landing gear was fully retracted. Aural warning identical to that heard when testing the stall warning alert in all aspects. Flight was completed without further warning activations or any other abnormalities. Maintenance personnel advised of event on arrival to XXX and given data included in this report. Aircraft flown by the same crew on 3 subsequent flight segments without further problems. Deicing occurred on 2 segments due to in-flight ice accumulations. Occurrence was treated as transient fault in system and was not recorded in aircraft discrepancy log. Maintenance personnel did perform a visual and operational check of vane sensor for contamination and foreign objects. No problems were found. Transient faults, one time events, are routinely not recorded in adl's while evaluated by maintenance personnel and some level of inspection performed. This is common throughout the industry. Some guidelines as to what system or warnings must be excluded from this practice need to be established. During the event in this report, the warning began sounding while the aircraft was still in a 3-POINT stance on the ground but beyond V1. We were required to continue the takeoff and were readily able to determine it was a false warning. There were sufficient outside references in addition to instrument references to confirm there was no stall occurring throughout rotation, liftoff, and initial climb. We also had the forewarning of a previous occurrence. While that event seemed questionable to us, we knew it was possible, there was a considerable amount of time and cognitive effort expended continuously confirming there was no stall. This distraction was occurring during a critical phase of flight when margins for error are small. No pilot will lightly disregard a stall warning. Only with a considerable effort in xchking other references will a pilot make a determination that the warning is to be ignored. This requires sufficient time and data to be certain.

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Original NASA ASRS Text

Title: FLC OF BE1900D HAS STALL WARNING ACTIVATE AFTER V1. COMPANY POLICY FOLLOWED AND TKOF CONTINUED. ALL INDICATIONS ARE THAT THIS IS A FALSE WARNING AND FLT CONTINUES.

Narrative: ACFT ARRIVED LNK AS FLT XXXX WITH THIN LAYER MIXED ICE COVERED WITH IMPACT SNOW ON LEADING EDGE SURFACES. DEICED PER FOPM MANDATED DEICING PROCS. CREW COMPLIED WITH ALL FOPM DEICING AND ANTI-ICING PROCS INCLUDING A SECOND VISUAL INSPECTION, PRE-TKOF CONTAMINATION CHK OF BOTH WINGS. NECESSITATED BY DECREASED VISIBILITY VALUE RECEIVED FROM TWR REDUCED HOLDOVER TIME TO A RANGE OF 9- 12 MINS. NEITHER WING HAD ANY VISIBLE SIGNS OF CONTAMINATION. DURING TKOF ROLL BTWN FO'S CALLOUTS OF V1 AND VR COCKPIT AURAL STALL WARNING HORN BEGAN SOUNDING CONTINUOUSLY. CONTINUED SOUNDING THROUGH ROTATION AND GEAR RETRACTION WITHOUT INTERRUPTION, CHANGES IN TONE, OR VOLUME. AURAL WARNING CEASED A FEW SECONDS AFTER LNDG GEAR WAS FULLY RETRACTED. AURAL WARNING IDENTICAL TO THAT HEARD WHEN TESTING THE STALL WARNING ALERT IN ALL ASPECTS. FLT WAS COMPLETED WITHOUT FURTHER WARNING ACTIVATIONS OR ANY OTHER ABNORMALITIES. MAINT PERSONNEL ADVISED OF EVENT ON ARR TO XXX AND GIVEN DATA INCLUDED IN THIS RPT. ACFT FLOWN BY THE SAME CREW ON 3 SUBSEQUENT FLT SEGMENTS WITHOUT FURTHER PROBS. DEICING OCCURRED ON 2 SEGMENTS DUE TO INFLT ICE ACCUMULATIONS. OCCURRENCE WAS TREATED AS TRANSIENT FAULT IN SYS AND WAS NOT RECORDED IN ACFT DISCREPANCY LOG. MAINT PERSONNEL DID PERFORM A VISUAL AND OPERATIONAL CHK OF VANE SENSOR FOR CONTAMINATION AND FOREIGN OBJECTS. NO PROBS WERE FOUND. TRANSIENT FAULTS, ONE TIME EVENTS, ARE ROUTINELY NOT RECORDED IN ADL'S WHILE EVALUATED BY MAINT PERSONNEL AND SOME LEVEL OF INSPECTION PERFORMED. THIS IS COMMON THROUGHOUT THE INDUSTRY. SOME GUIDELINES AS TO WHAT SYS OR WARNINGS MUST BE EXCLUDED FROM THIS PRACTICE NEED TO BE ESTABLISHED. DURING THE EVENT IN THIS RPT, THE WARNING BEGAN SOUNDING WHILE THE ACFT WAS STILL IN A 3-POINT STANCE ON THE GND BUT BEYOND V1. WE WERE REQUIRED TO CONTINUE THE TKOF AND WERE READILY ABLE TO DETERMINE IT WAS A FALSE WARNING. THERE WERE SUFFICIENT OUTSIDE REFS IN ADDITION TO INST REFS TO CONFIRM THERE WAS NO STALL OCCURRING THROUGHOUT ROTATION, LIFTOFF, AND INITIAL CLB. WE ALSO HAD THE FOREWARNING OF A PREVIOUS OCCURRENCE. WHILE THAT EVENT SEEMED QUESTIONABLE TO US, WE KNEW IT WAS POSSIBLE, THERE WAS A CONSIDERABLE AMOUNT OF TIME AND COGNITIVE EFFORT EXPENDED CONTINUOUSLY CONFIRMING THERE WAS NO STALL. THIS DISTR WAS OCCURRING DURING A CRITICAL PHASE OF FLT WHEN MARGINS FOR ERROR ARE SMALL. NO PLT WILL LIGHTLY DISREGARD A STALL WARNING. ONLY WITH A CONSIDERABLE EFFORT IN XCHKING OTHER REFS WILL A PLT MAKE A DETERMINATION THAT THE WARNING IS TO BE IGNORED. THIS REQUIRES SUFFICIENT TIME AND DATA TO BE CERTAIN.

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.