A combustion chamber includes an upstream end wall having an aperture and a fuel injector. An air swirler is mounted such that the air swirler is movable radially with respect to the aperture. An inner wall of the air swirler has a first portion. A fuel injector head of the fuel injector is arranged coaxially within the air swirler. An outer wall of the fuel injector head has a first portion. The inner diameter of the first portion of the air swirler is less than the outer diameter of the first portion of the fuel injector head. One of the first portions is elastically radially deformable to allow the fuel injector head to be installed and removed from the air swirler. The inner wall and the outer wall have inter-engaging radially and axially extending faces to align the fuel injector head axially and radially within the air swirler.