What happened
During the takeoff roll, the pilot observed that the airspeed indicator was still indicating zero despite the aircraft accelerating down the runway. In response to this reading, the pilot closed the throttle and applied the brakes. The aircraft subsequently departed the end of the 1,550-foot long turf/gravel runway and traveled down an embankment.
A witness observing the takeoff noted that at the midfield point of the runway, the aircraft appeared to be traveling slower than normal. This witness further reported that no reduction in engine power was heard until the aircraft had utilized approximately 3/4 of the available runway length.
The investigation
Post-accident examination of the aircraft revealed that the pitot tube, which was positioned under the left wing, was missing. Investigators conducted a search of the accident site and the taxi route used for departure, but they were unable to locate the missing pitot tube.