What happened
During the final approach phase to Pittsburgh-Allegheny County Airport, the aircraft encountered severe difficulties while descending. At an altitude of approximately 500 feet above the ground, the machine rolled sharply to the left. This maneuver triggered an uncontrolled descent that could not be recovered by the crew. The aircraft ultimately impacted the terrain short of the runway, resulting in a fatal accident. All 13 occupants were killed in the crash.
Findings
The US Bureau of Air Commerce investigated the incident and identified ice accumulation as the primary factor. Investigators determined that ice had built up on the wings and specifically within the slot area between the aileron edges and the wingtips. This specific configuration altered the airfoil contour, which disrupted the airflow around the structure. The resulting aerodynamic instability led to a complete loss of control. In response to this accident, improved deicing equipment was subsequently developed to mitigate the dangers posed by ice buildup on aircraft.