A fuel supply system for an aircraft engine, comprising: a gaseous fuel source; and a fuel nozzle including: a housing having a housing interior chamber; and a fuel swirler (40, 50; 40') disposed inside the housing interior chamber, the fuel swirler (40, 50; 40') fluidly connected to the gaseous fuel source for directing gaseous fuel to a combustor of an aircraft engine, the fuel swirler (40, 50; 40') defining a gaseous fuel path extending from a fuel inlet to a fuel outlet, the gaseous fuel path including a plurality of discrete apertures (46a; 84) distributed around a circumference of the fuel swirler (40, 50), characterized in that the plurality of discrete apertures are defined through a radially exterior surface of the fuel swirler relative to a longitudinal axis of the fuel swirler, wherein the plurality of discrete apertures are positioned at the fuel inlet of the fuel swirler, wherein each of the plurality of discrete apertures (46a; 84) has a cross-sectional area selected to prevent a flame from propagating in an upstream direction through the gaseous fuel path towards the gaseous fuel source, and wherein the plurality of discrete apertures (46a; 84) have cross-sectional diameters of at most 0.610mm (0.024 inches). a gaseous fuel source; and a fuel nozzle including: a housing having a housing interior chamber; and a fuel swirler (40, 50; 40') disposed inside the housing interior chamber, the fuel swirler (40, 50; 40') fluidly connected to the gaseous fuel source for directing gaseous fuel to a combustor of an aircraft engine, the fuel swirler (40, 50; 40') defining a gaseous fuel path extending from a fuel inlet to a fuel outlet, the gaseous fuel path including a plurality of discrete apertures (46a; 84) distributed around a circumference of the fuel swirler (40, 50), characterized in that the plurality of discrete apertures are defined through a radially exterior surface of the fuel swirler relative to a longitudinal axis of the fuel swirler, wherein the plurality of discrete apertures are positioned at the fuel inlet of the fuel swirler, wherein each of the plurality of discrete apertures (46a; 84) has a cross-sectional area selected to prevent a flame from propagating in an upstream direction through the gaseous fuel path towards the gaseous fuel source, and wherein the plurality of discrete apertures (46a; 84) have cross-sectional diameters of at most 0.610mm (0.024 inches). a housing having a housing interior chamber; and a fuel swirler (40, 50; 40') disposed inside the housing interior chamber, the fuel swirler (40, 50; 40') fluidly connected to the gaseous fuel source for directing gaseous fuel to a combustor of an aircraft engine, the fuel swirler (40, 50; 40') defining a gaseous fuel path extending from a fuel inlet to a fuel outlet, the gaseous fuel path including a plurality of discrete apertures (46a; 84) distributed around a circumference of the fuel swirler (40, 50), characterized in that the plurality of discrete apertures are defined through a radially exterior surface of the fuel swirler relative to a longitudinal axis of the fuel swirler, wherein the plurality of discrete apertures are positioned at the fuel inlet of the fuel swirler, wherein each of the plurality of discrete apertures (46a; 84) has a cross-sectional area selected to prevent a flame from propagating in an upstream direction through the gaseous fuel path towards the gaseous fuel source, and wherein the plurality of discrete apertures (46a; 84) have cross-sectional diameters of at most 0.610mm (0.024 inches).