On September 21, 1999, a Cessna 172P (registration N63325) was involved in an aviation accident near Friendly, MD. Investigators recorded the probable cause as: Obstructed pitot tube. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During an instrument training flight, a private pilot reported an inoperative airspeed indicator after takeoff. The flight instructor took over and aborted two landing attempts before overrunning the runway on the third, colliding with a ditch. Post-accident inspection revealed an obstructed pitot tube.
Departure and Initial Climb
A flight instructor and a private pilot departed on an instrument training flight in instrument meteorological conditions. The private pilot performed the takeoff and, during the climbout, announced that the airspeed indicator was inoperative.
Return and Landing Attempts
The flight instructor then assumed control of the airplane and returned to the airport for landing. The instructor attempted two landings but aborted both attempts. On the third approach, the airplane touched down, overran the runway, and collided with a ditch.
Post-Accident Examination
Examination of the airplane after the accident revealed that the pitot tube was obstructed.