Flight Details
The airplane was on a southerly heading at an altitude of 13,000 feet in instrument meteorological conditions. Over a 23-second period, it turned toward the west, descended approximately 1,200 feet, and then broke up. The last recorded 3-point smoothed ground speed was 242 knots. Winds aloft were from the east at about 10 knots.
Speed Limitations
The airplane's maximum operating speed was 167 knots indicated, and its maximum maneuvering speed was 141 knots indicated.
Icing Conditions
At the time of the accident, the airplane was operating in conditions conducive to icing. The airframe anti-icing system was inoperative. It was undetermined whether the engine and pitot ice protection systems had been activated. An AIRMET calling for icing was in effect, but this information was not mentioned during the Ontario weather briefing. In Buffalo, no flight service station services were requested or provided.
Structural Failure
Examination of the wreckage revealed that the horizontal stabilizer and the wings exhibited markings consistent with downward overstress separation.
Operational Context
The flight originated from Hamilton, Ontario, and made a stop at Buffalo, New York, before continuing. Flight into icing conditions was prohibited for this airplane; the prescribed procedure was to turn back or change altitude to escape the icing.