Narrative:

Normal start and taxi. Began normal takeoff. At 100 KTS; standard call and acknowledgement made. Above 100 KTS; our company policy on rejected takeoff is only if we have a fire; engine failure; or perception that plane will not fly. At approximately 120 KTS; first officer called that airspeed was not increasing. I elected to abort takeoff. Thrust reverser and normal braking brought aircraft to controlled stop. At time of abort; captain's asi showed approximately 120 KTS. First officer told me that his asi indicated approximately 140 KTS. Since airspeed information was; in my opinion; not reliable; I elected to reject takeoff. I'm sure the plane would have gotten off the ground (V1 was 148 KTS); but I wasn't confident in the information that the instruments were giving me reliable information. I had 40 people in the cabin; lots of runway and about 2 seconds to make a decision. My preliminary discussions with my flight standards department and chief pilots indicate that I violated company policy and the investigation will continue. I stand by my decision and subsequent actions. A little voice in my head told me that something was just not right with the airplane. Subsequent investigation by maintenance discovered that an air data computer had failed which would not provide reliable airspeed information. No caution message was annunciated possibly due to inhibition by onboard software that inhibits certain messages above 100 KTS.

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Original NASA ASRS Text

Title: CL65 Captain reports rejecting takeoff at about 140 knots when airspeed indication is deemed unreliable. Captain is later by the Chief Pilot for violating company policy on high speed aborts.

Narrative: Normal start and taxi. Began normal takeoff. At 100 KTS; standard call and acknowledgement made. Above 100 KTS; our company policy on rejected takeoff is only if we have a fire; engine failure; or perception that plane will not fly. At approximately 120 KTS; First Officer called that airspeed was not increasing. I elected to abort takeoff. Thrust reverser and normal braking brought aircraft to controlled stop. At time of abort; Captain's ASI showed approximately 120 KTS. First Officer told me that his ASI indicated approximately 140 KTS. Since airspeed information was; in my opinion; not reliable; I elected to reject takeoff. I'm sure the plane would have gotten off the ground (V1 was 148 KTS); but I wasn't confident in the information that the instruments were giving me reliable information. I had 40 people in the cabin; lots of runway and about 2 seconds to make a decision. My preliminary discussions with my Flight Standards Department and Chief Pilots indicate that I violated company policy and the investigation will continue. I stand by my decision and subsequent actions. A little voice in my head told me that something was just not right with the airplane. Subsequent investigation by Maintenance discovered that an ADC had failed which would not provide reliable airspeed information. No caution message was annunciated possibly due to inhibition by onboard software that inhibits certain messages above 100 KTS.

Data retrieved from NASA's ASRS site as of April 2012 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.