The invention relates to an aircraft (5) comprising: a structure (6); a landing gear (1) mounted on the structure (6) of the aircraft; and at least one obstacle detector (2). The aircraft (5) is characterised in that the obstacle detector (2) is secured to an arm (3), said arm (3) being mounted on the structure (6) such that it can move between a rest position in which the arm (3) is retracted and a detection position in which the arm (3) is deployed such that the obstacle detector (2) extends close to a lower portion of the landing gear (1) at a distance from the structure (6) of the aircraft (5).