A Virgin Australia ATR 72 operating a flight from Moranbah to Brisbane had to conduct a go-around after an incorrect flap settings was selected on approach, the Australian Transport Safety Board (ATSB) says.
The incident occurred on April 2 2017 when ATR 72-500 VH-FVL, with 38 passengers and four crew onboard, was turning onto final approach for Brisbane Airport’s Runway 19.
At that time, the captain, who was the pilot flying, directed the first officer, who was the pilot monitoring, to select flap 30, set the airspeed indicator bug to the approach speed (VAPP) and start the before landing checklist.
However, the ATSB report said the flightcrew noticed during final approach the aircraft was “not performing as expected”, with its airspeed higher than during a normal approach.
“The captain had to keep adjusting the aircraft attitude and engine torque setting to control the speed,” the ATSB said.
Later, as the aircraft descended to 173ft, the enhanced ground proximity warning system activated with the alert, “TOO LOW FLAP”.
The captain then immediately conducted a missed approach and during the subsequent climb, called “flap 15, check power” and the first officer responded accordingly.
The aircraft then conducted the same approach to Runway 19 and after landing the captain decided to stand the crew down and not conduct the next two sectors.
Flight data showed the flaps were incorrectly set for conducting a normal landing.
“During the approach, the first officer moved the flap lever up from flap 15 to flap 0, instead of from flap 15 to flap 30 as intended. This resulted in an unstable approach,” the ATSB report said.
“The crew did not identify the incorrect flap setting until the ground proximity warning system alerted them to an incorrect configuration, likely due to workload.”
The ATSB report said the first time the captain became aware of that the flap was set to 0 degrees was during a review of the flight data animation conducted by the airline.
“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),” the ATSB said.
Meanwhile, the ATSB report noted the workload of the crew increased during the approach, when there was a combination of turning onto he final approach path, conducting a visual approach, managing radio calls with air traffic control and responding to the unexpected aircraft performance.
“Flap settings are generally confirmed through the completion of the before landing checklist, whereby the flap lever and indicator must be visually checked,” the ATSB report said.
“However, in this case, this part of the checklist happened during a high workload period, and it was subsequently rushed. This checklist item may have been missed.
“This investigation highlights the potential impact crew workload has on flight operations as it can lead to adding, shedding, or rescheduling actions. Handling approaches to land continues to be a safety priority for the ATSB.”