Boeing has confirmed a report from Flightblogger that it is working on a design fix for the 747-8 following unexpected buffeting during test flying, potentially putting pressure on the delayed airliner’s expected certification and delivery dates.
The issue surfaced on the first flight of the first 747-8 Freighter on February 10, and occurred when the aircraft’s flaps were extended to maximum deflection at 30 degrees while the landing gear was down. The reportedly “very apparent” buffeting was traced back to disruptive airflow caused by the aircraft’s outboard landing gear doors.
Boeing is understood to be examining different solutions to the issue, such as reducing the maximum deflection of the double slotted flaps to 27 degrees. Sources claim that an alternative solution involving adding vortex generators to the inboard flaps to redirect airflow has been ruled out due to complications it would create with the overwing emergency exit slides.