United Airlines Flight 232 was a scheduled flight operated by United Airlines between Denver and Philadelphia via Chicago. On July 19, 1989, the Douglas DC-10 (Registration N1819U) being operated for this flight suffered an uncontained failure of its number 2 engine (mounted in the tail), which destroyed all three of the aircraft’s hydraulic systems. With no controls working except the power levers for the two remaining engines, it broke up during an emergency landing on the runway at Sioux City, Iowa killing 110 of its 285 passengers and one of the 11 crew members. Owing to the skill of the crew and a DC-10 instructor pilot, 175 passengers and 10 crew members survived the crash, which is considered a textbook example of successful Crew Resource Management, due to the effective use of all the resources available aboard the plane for help during the emergency.