A door assembly, in particular for a helicopter, has a post; a door fitted to the post by a first and second hinge arranged on an outer wall of the post, so as to rotate about a hinge axis to open and close a door opening; and an emergency release device having a release handle, and a stem which extends through the post along a release axis substantially perpendicular to the hinge axis, rotates axially, in response to operation of the release handle, from a first to a second angular position to detach the door from the post, and is fixed at one axial end to the first hinge; the release handle being connected to the stem to rotate together with the stem about its release axis.