A method is provided for supplying a liquid fuel to a gas-turbine engine, e.g. aviation engine. It includes selective fuel delivery through several fuel delivery lines for different engine operating modes based on a required engine power, providing, e.g. feeding the engine operating at minimal power with base or traditional for this type of engine fuel through a base fuel delivery line; in other operating modes the fuel is fed to the engine either through conditioned fuel delivery line with preliminary conditioning of base fuel or through both said fuel delivery lines simultaneously with mixing both fuel flows directly before entering an engine combustion chamber, e.g., in a line connecting intake manifold for the base fuel and each individual fuel injector.