On May 21, 2001, a Beech 55 (registration N4783M) was involved in an aviation accident near West Chester, PA. Investigators recorded the probable cause as: The partial blockage of the pitot/static system, which led to an inaccurate airspeed indication, and resulted in an aborted takeoff and runway overrun. A factor was the wet runway. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot aborted takeoff after airspeed indicator failed to exceed 65 knots, but the aircraft overran the runway and stopped in a parking lot. Examination revealed a blocked pitot tube and a faulty airspeed indicator.
Incident Overview
During the takeoff roll, the pilot reported that the airspeed indicator did not exceed 65 knots. He subsequently aborted the takeoff, but the airplane continued off the end of the runway and came to rest in a parking lot.
System Examination
An airspeed calibration test was conducted, which revealed that the airspeed indicator read approximately 10 knots higher than the test equipment. Further inspection of the pitot-static system found that the pitot tube was obstructed with a "corrosion-type material."
Airspeed Indicator Bench Test
The airspeed indicator was removed from the airplane and bench tested. The bench test showed that the indicator read approximately 4–5 knots higher than the test equipment.
Previous System Check
The most recent pitot-static system check had been performed on March 14, 2001.