Marine One is the call sign for any U.S. Marine Corps helicopter carrying the president, with the current fleet—dubbed "White Tops"—featuring the VH-3D Sea King, the newer VH-92A Patriot, and the smaller VH-60N. The tradition began in 1957 when President Dwight D. Eisenhower used a Bell UH-13J Sioux to reach his summer home, later replaced by the Sikorsky H-34 and VH-3A, with the VH-3D and VH-60N entering service in 1978 and 1987 respectively. The Marine Corps shared this duty with the Army until 1976, and the White House South Lawn became a standard landing zone. In 2009, Marine One flew with an all-female crew for the first time, and it has never had an accident or been attacked, though a 2006 mechanical failure once forced President George W. Bush to use a car. After the September 11 attacks, weight limitations prevented necessary security upgrades, prompting the VXX program in 2002 to design a new helicopter with advanced defenses like radar jamming, encrypted communications, and a range greater than its predecessors. The new aircraft was to be 64 feet long, carry 14 passengers, and be ready by 2008, though the program faced significant delays.