They are a special race of technicians. With their white blouses and their delicate way of feeling round the surface of aircraft, they ressemble doctors. Their role in the maintenance of aircraft is primordial: they analyse the structure, but without taking the planes to pieces. They start work when the plane needs an overhaul, or after a collision with birds, with material on the runway, or an overly rough landing… Just like doctors, they work to establish a diagnostic on the aircraft in their care.