A method of inducing swirl in pressurized air flowing through an air passageway of a fuel nozzle of a gas turbine engine includes inducing swirl in the pressurized air at an exit of the air passageway, by directing the pressurised air through helicoidal grooves formed at a downstream end of the air passageway. The swirling pressurized air exiting the air passageway is then directed into a mixing zone at a downstream end of the fuel nozzle.