A combustor is provided for mounting a fuel injector to a gas turbine engine. The combustor comprises an engine casing having an aperture formed therein. The system further comprises a fuel injector having a flange for mounting the fuel injector to the casing at the aperture so that the fuel injector extends into the engine. The flange is dismountably sealed to an inner side of the casing. The aperture and flange are configured so that, when dismounted, the fuel injector can be rotated into an orientation relative to the aperture which allows the flange to pass though the aperture and the fuel injector to be withdrawn from the casing.