September’s issue of NASA’s Aviation Safety Reporting System (ASRS) Callback shares challenges, hazards, and lessons learned during visual approaches. One such incident report submitted by a Bombardier Challenger 350 captain involved a wake-turbulence encounter.
After the business jet crew was cleared for a visual approach to Runway 28L at San Francisco International Airport (KSFO), approach control called out a Boeing 777 that would be landing on the parallel runway. The pilots were told to keep the B777 in sight, which they acknowledged, and were cautioned about wake turbulence.
“After joining the final, we began a descent,” the captain said. “At about 2,800 feet, we encountered wake turbulence, and the aircraft abruptly rolled left to approximately 70 degrees followed by an immediate roll to the right of approximately 70 degrees.” The first officer, the flying pilot, countered both roll excursions with opposite aileron, and the aircraft quickly recovered to level flight, continued the approach, and landed.
Although the captain estimated that the horizontal distance between the Challenger and the B777 was two to three miles, “both the lateral offset and horizontal spacing [were] insufficient,” said the captain. He added that the wind on final was different than reported by ATIS and may have blown the vortices toward the aircraft.