Poor aeronautical decision-making coupled with stormy weather, an overweight aircraft and an overly ambitious trip itinerary led to the crash of a private general aviation aircraft that killed a young girl, her father and a flight instructor last year, the National Transportation Safety Board (NTSB) said today.
The accident occurred on April 11, 1996, shortly after a Cessna 177B took off from a Cheyenne, Wyoming, airport as part of a highly-publicized cross country trip by seven-year-old Jessica Dubroff.
At a public meeting in Washington, D.C., the NTSB determined the accident's probable cause was the improper decision by the flight instructor, who was the pilot in command, to takeoff into deteriorating weather conditions. Weather included air turbulence, gusty winds, an advancing thunderstorm and associated precipitation.
The four-seat airplane was overweight and the density altitude was higher than the flight instructor was accustomed to -- which resulted in a stall caused by failure to maintain airspeed.
Contributing to the pilot in command's decision to take off was a desire to adhere to an overly ambitious itinerary, in part because of media commitments, the NTSB said.
To prevent similar accidents, the NTSB issued three safety recommendations. It urged the Aircraft Owners and Pilots Association, the Experimental Aircraft Association and the National Association of Flight Instructors to continue to emphasize the importance of proper aeronautical decision-making to its members.
The Safety Board also urged the Federal Aviation Administration to incorporate the lessons of this accident into educational materials on aeronautical decision-making and expand information and dissemination of materials on the hazards of fatigue to general aviation pilots.
The board reached numerous other conclusions about the accident including:
The pilot in command was at least assisting Jessica Dubroff, the pilot trainee -- if he was not the sole manipulator of the controls -- during the takeoff and climb-out sequence. At the time of impact, the pilot in command was the sole manipulator of the airplane's controls.
There was no evidence that airplane maintenance was a factor in the accident and there was no evidence of airframe, engine or control malfunction during the takeoff and subsequent crash. Airframe icing was not likely a factor and there were no air traffic control factors that contributed to the cause of the accident.
The airplane was 96 pounds over maximum gross takeoff weight at takeoff, and 84 pounds over the maximum gross takeoff weight at the time of the impact.
The airplane experienced strong crosswinds, moderate turbulence and gusty winds during its takeoff and attempted climb, and the pilot in command was aware of these adverse wind conditions prior to takeoff.
The accident sequence took place near the edge of a thunderstorm and the pilot in command decided to turn right immediately after takeoff to avoid the thunder-storm and heavy rain that would have been encountered on a straight-out departure.
The right turn into a tailwind may have caused the pilot in command to misjudge the margin of safety above the airplane's stall speed. In addition, the pilot may have increased the airplane's pitch angle to compensate for the perceived decreased climb rate, especially if the pilot misperceived the apparent ground speed for airspeed, or if the pilot became disoriented.
The high density altitude and possibly the pilot in command's limited experience with this type of takeoff contributed to the loss of airspeed that led to the stall.
The pilot in command suffered from fatigue during the day before the accident, and information on fatigue and its effects, and methods to counteract it, might have assisted the pilot to recognize his own fatigue on the first day of the flight, and possibly enhanced the safety of the flight.
This press release and other NTSB information are available on the World Wide Web: http://www.ntsb.gov