Sequence of Events
During takeoff roll on an asphalt-surfaced runway measuring 3,366 feet in length and 75 feet in width, the pilot elected to abort the takeoff after the engine began to run rough. The airplane subsequently exited the runway and collided with a ditch.
Accounts from the three passengers varied regarding engine performance. One passenger reported that the engine appeared to hesitate but did not misfire, while the remaining two passengers stated the engine sounded normal. The passengers indicated that the abort occurred when the airplane was between one-half and three-quarters of the distance down the runway.
Weight and Balance
The pilot reported calculating the airplane's weight and balance before departure and found them within limits. However, safety board investigators performed their own calculations using the actual occupants' weights and an estimate of their personal baggage weights. These calculations disclosed that the airplane exceeded its maximum allowable gross weight by 215.7 pounds. The center of gravity was determined to be within its normal range.
Engine Examination
A post-accident examination of the engine revealed no evidence of any preimpact malfunctions or failures.