Airbus is drafting a worldwide safety warning about electrical problems on some of its aircraft.
The company is investigating a fault that temporarily affected primary cockpit displays and computer controls on a BMI flight from Khartoum to Beirut in August.
The standby instruments on the A321 plane did operate normally.
The pilots eventually regained control of the aircraft - but by that time it was 20 miles off its course.
The pilots reported that without warning the aircraft began to shudder, banking steeply on its own - failing to respond to pilot commands over a period of several minutes.
The twin-engined jet with 49 people aboard was cruising at 36,000ft.
The crew said they were bombarded by a stream of warning messages before cockpit screens turned grey and then went blank.
The aircraft's left wing suddenly dropped without any input from the crew.
For years, safety investigators have been concerned about electrical system glitches resulting in dangerous shutdowns of flight control computers.
But such incidents are hard to understand and replicate. Airbus says it is helping both the Air Accident Investigation Branch (AAIB) and the BEA in France with the inquiry.
But it has been reported that investigators have already urged Airbus to alert all operators of its A319, A320 and A321 planes about the potential hazards stemming from such electrical faults.