What happened
A BAe-748 cargo aircraft was destroyed while performing an approach to Ottawa International Airport in Ontario, Canada. The flight originated from Montreal-Dorval International Airport, having previously completed a cargo transport from Dayton, Ohio. After unloading its payload in Montreal, the aircraft departed for Ottawa at 09:58 under instrument flight rules.
The flight proceeded normally until approximately 10:19, while cruising at 3,000 feet and 200 knots. Flight data records indicate a sudden, extreme movement of the control surfaces, specifically a full upward deflection of the left aileron and a full downward deflection of the right aileron. This triggered a rapid roll to the left. During this ten-second window, the aircraft rolled approximately 460 degrees while the nose pitched down significantly.
Following this intense maneuver, the ailerons returned toward a neutral position, but the aircraft remained in a steep bank of about 90 degrees. The flight ended when the aircraft struck the ground at an airspeed of roughly 290 knots with a pitch angle of 41 degrees downward. The total duration from the initial control surface deflection to the impact was approximately 18 seconds. The accident resulted in two fatalities.
Findings
Investigations revealed that the aileron control system had been asymmetrically rigged, which created a vulnerability to aerodynamic overbalance. It was determined that the operator failed to perform necessary flight tests of the aileron response following maintenance.
Additional contributing factors included the specific design of the aileron system and maintenance documentation that was both incomplete and ambiguous. The investigation also noted a lack of published emergency procedures for the crew regarding aileron performance, as well as potential issues related to flight crew fatigue.