When the U.S. military moves casualties long distances, it usually uses a C-141 or C-17 transport. The C-17 aircraft, in particular, was designed for quick conversion to this task. These Aeromedical evacuation missions often last 24 hours and involve 40-50 patients. Ten personnel from an Aeromedical Evacuation Squadron staff the C-17 during the flight. These include three flight nurses and four technicians to take care of the patients, and a critical care team (one doctor, one critical care nurse and a respiratory technician) for emergencies. Aeromedical Evacuation Squadrons have 450 personnel, many of them in the reserves.