Accident Sequence
Following a normal run-up, the copilot taxied the aircraft to the end of the 5,010-foot runway. The aircraft was lined up slightly to the right of the centerline, the tail wheel was locked, and power was applied. As the aircraft accelerated, the tail rose, and the copilot applied forward pressure on the control column. Shortly afterward, the airplane began swerving left; corrective input caused an over-correction to the right. A series of over-corrections resulted in several swerves in both directions.
During these maneuvers, the crew noted a five-inch drop in the manifold pressure of the left engine. At approximately 80 knots, the aircraft again turned left. The captain immediately took over the controls when he observed a second drop of 25 inches in manifold pressure of the same engine. Both throttles were closed simultaneously, but the captain was unable to stop the turn. The turn developed into a skid, causing the main landing gear to collapse and rupturing the right wing fuel tank. The aircraft came to rest on the sodded area off the runway, facing 180 degrees from its original takeoff heading. Fire immediately occurred near the right engine nacelle.
Evacuation and Weather
Under the stewardess's supervision, all passengers exited the aircraft rapidly and orderly through the main cabin door. The pilots left through the cockpit windows. The captain and copilot re-entered the cabin to recheck after all passengers were reported out and away from the aircraft.
Local weather conditions: ceiling 30,000 feet scattered, 600 feet scattered, visibility 12 miles, temperature 70°F, dewpoint 67°F, wind south 7 knots. Atmospheric conditions were not conducive to carburetor ice.
Probable Cause (Official Findings)
The Board determined that the probable cause of this accident was the copilot's loss of directional control during the takeoff run and the inability of the captain to regain control of the aircraft, the latter possibly due to failure of the pedal mechanism. The following findings were reported: directional control was lost in the takeoff run, resulting in a violent ground loop off the runway; there is no evidence indicating structural failure or malfunction of controls, but there exists the indeterminable possibility that during the takeoff run there was a failure of the pedal assembly; subsequent engine tests gave no evidence of other than normal operation of the left engine; the right engine operated normally throughout the attempted takeoff.