What happened
During the takeoff roll, the pilot of the aircraft attempted to abort the takeoff after noticing that the airspeed indicator was malfunctioning. While the indicated airspeed initially rose to approximately 60 knots, it failed to increase further despite the pilot's efforts to rectify the gauge reading by tapping on the instrument face.
In response to the unreliable instrumentation, the pilot reduced power by pulling back the throttles and applied maximum braking. However, the aircraft was unable to stop within the 4,451-foot runway. The plane overran the end of the runway, descended down a hill, and eventually collided with a fence. The pilot had previously noted that under the prevailing conditions, the aircraft was capable of accelerating to rotation speed and returning to a stop within a distance of less than 3,500 feet.
Findings
An inspection of the aircraft following the accident identified the primary reason for the instrumentation failure. The pitot tube was found to be internally blocked by a combination of mud and an insect.