Approach
The approach and landing phase is known for high workload due to the numerous tasks required alongside flight path monitoring. During the approach, as the aircraft was turning, the first officer was responding to a radio call and completing a checklist.
Incident
It is likely that the first officer inadvertently selected the flap lever up from 15 to 0, instead of down to 30, and did not crosscheck the flap indicator before proceeding with other tasks. This inadvertent action caused an increase in the aircraft’s airspeed, which the flight crew recognized but were unable to explain at the time. The incorrect flap setting was not detected, and a go-around was initiated after a ground proximity warning alerted the crew to an incorrect configuration at 173 feet.
Stabilized Approach Criteria
Due to the high workload in managing the aircraft’s performance on approach, the crew did not detect that the aircraft’s speed was exceeding the stabilised approach criteria of VAPP + 10 knots or that the aircraft was incorrectly configured with flaps at 0. Although at 507 feet the airspeed was 114 knots, which was within the stabilised approach criteria with the VAPP set at 104 knots, at 358 feet the airspeed had increased to 128 knots, which was outside the stabilised approach criteria.
Potential Stall Risk
Since the incorrect flap setting was not detected by the crew on approach, had they managed to slow the aircraft to the VAPP of 104 knots for flap 30, they would have been 2 knots below the stall speed for the actual flap setting (106 knots).