The CH-46 Sea Knight is a medium-lift, tandem rotor cargo helicopter used by the U.S. Marine Corps to provide all-weather, day-or-night transport of combat troops, supplies and equipment. Troop assault is the primary function and the movement of supplies and equipment is secondary. Additional tasks may be assigned such as combat support, search and rescue, support for forward refueling and rearming points, aeromedical evacuation of casualties from the field and recovery of aircraft and personnel.