Pilots in CL604 Upset Use Clouds for Attitude Recovery

 - May 16, 2017, 5:06 PM
While this Challenger 604 displays no outward damage, Bombardier determined that the airframe could not be restored to airworthiness since it had exceeded several maximum loads while tangling with an A380's wake vortex in January over the Arabian Sea. (Photo: BFU)

A review of the newly released interim report on a wake vortex encounter shows how close a Bombardier Challenger 604 came to crashing into the sea in January. While flying over the Arabian Sea, the pilots temporarily lost control of their twin-turbine business jet when it flew into the wake from an Airbus A380 flying in the opposite direction that was 1,000 feet overhead and slightly to the right.

Approximately a minute after the two aircraft passed each other, the Challenger hit turbulence from the A380’s wake and quickly went out of control. Before the crew regained control at FL240, the aircraft had exceeded several design load limits, rolled several times, dropped 8,700 feet, lost vital avionics (including attitude displays) and the left engine had to be caged. The pilot-flying explained that since the sky and the ocean were almost the same blue color, he had been able to recognize the aircraft's flight attitude only “with the help of the clouds.”

After the crew regained control, they declared an emergency and diverted to an alternate airport, where they made a normal landing. Although no external damage could be seen (in contrast to that in the cabin), Bombardier determined that the airframe structure could not be restored to airworthy condition. Two passengers were severely injured and one passenger and the flight attendant sustained minor injuries.