What happened
The aircraft departed from an airport with a center of gravity positioned between 95.45 and 95.71 inches aft of the datum. This configuration placed the center of gravity approximately 98 pounds below the maximum allowable gross weight, but it significantly exceeded the maximum aft center of gravity limit of 94.6 inches for all weights. The weather conditions at the approximate time of the accident included a ceiling of 400 feet, light snow showers, and visibility of four miles with fog. The temperature was 29 degrees Fahrenheit with a dew point of 29 degrees Fahrenheit. A significant meteorological advisory (SIGMET) for moderate to severe icing in clouds was also in effect.
The aircraft impacted the ground in a left bank angle between 30 and 40 degrees. The impact occurred approximately 1,800 feet from the departure end of the runway. There was no evidence of inflight mechanical malfunctions of the powerplants. Although the aircraft had arrived at Johnstown with ice on the wings and tail, the pilot received a full weather briefing and was aware of the icing conditions prior to his last takeoff. Evidence indicated that the pilot did not deice the aircraft's wings and tail prior to the accident flight.
The investigation
Investigators examined the aircraft's weight and balance data, finding the center of gravity was outside the allowable aft limit. They also reviewed weather reports confirming active icing conditions and noted the lack of deicing procedures before departure. No mechanical failures were found in the powerplants.
Findings
The primary factors contributing to this accident were the improper loading of the aircraft resulting in an aft center of gravity beyond limits, and the failure to deice the aircraft prior to flight in known icing conditions.