Abstract: A door assembly for a payload bay (10) having an opening (12), the door assembly comprising at least one door (20, 220). The at least one door comprises: a panel section (22, 222) having a first end (24, 224) and a second end (26, 226); and a first mounting member (30, 230) arranged orthogonally to the panel section at the first end and having a first engagement feature (31, 231) having a rotational axis (18, 218) about which the panel section is arranged to rotate. The engagement feature is arranged to engage with a first fixing member (16, 216) on one side of the payload bay to rotatably couple the panel section to the payload bay. The at least one door is arranged to translate between a closed configuration, in which the panel section is arranged in the same plane as the opening, and an open configuration, in which the panel section is arranged at at least 90 degrees to the plane of the opening, by rotating about the rotational axis.