A FLIGHT crew who took three attempts to land a plane at the Ballina Byron Gateway Airport last year did not follow correct procedures, an investigation has revealed.

The crew received a "landing gear not down" master warning while on approach to the airport, which was triggered after an incorrect aircraft configuration following a go-around.

The Australian Transport Safety Bureau's investigation into the incident was finalised this week.

Transport safety director Dr Stuart Godley said during the flight from Sydney on May 18, 2018, the crew conducted a visual approach to land, with the first officer manually flying the Airbus A320.

But the captain realised the aircraft's airspeed and altitude were higher than normal.

Due to circuit traffic, the captain decided to have the plane established on final approach before commanding a go-around.

The ATSB found the flight crew did not follow standard procedures during the go-around and visual circuit at 1500ft.

The report found that:

● The flaps remained at Flaps 3 rather than Flaps 1 during the circuit

● This created a series of distractions leading to a non-standard aircraft configuration

● Limited use of available aircraft automation added to the flight crew's workload

● During the go-around, the flight crew did not select the landing gear down

● The flight crew incorrectly actioned the landing checklist, which prevented the incorrect configuration for landing being identified and corrected

● On the second approach, at about 700ft, a master warning was triggered because the landing gear had not been selected down.

The flight crew conducted a second go-around and landed without further incident on their third approach.

Dr Godley said the incident at the Ballina airport highlighted the importance of following standard operating procedures.

"Following standard procedures mitigates the risk of the selection of inappropriate auto-flight modes, unexpected developments, or confusion about roles or procedures that can contribute to decisions and actions that increase the safety risk to the aircraft and its passengers," he said.

"In this case a number of factors, such as distraction and limited use of aircraft automation, combined to result in the landing gear not being selected to down.

"While highly undesirable, it should be noted that the aircraft's warning system effectively alerted the flight crew to the problem and the crew responded promptly to the warning and initiated a second go-around."

Dr Godley said the incident reinforced how unexpected events during approach and landing phases can substantially increase what is already a high flight crew workload.