Both Army Aviation and the helicopter came of age during the conflict in Southeast Asia. The most widely used helicopter, the Bell UH-1 Iroquois, or Huey, began to arrive in Vietnam in significant numbers in 1964. Before the end of the conflict, more than 5,000 of these versatile aircraft were introduced into Southeast Asia. They were used for medical evacuation, command and control, air assault; personnel and materiel transport; and gunships. The AH-1 Cobra arrived in 1967 to partially replace the Huey in its gun ship capacity. Other important helicopters in Vietnam included the Boeing CH-47 Chinook, the Hughes OH-6 Cayuse, the Bell OH-58 Kiowa, and the Sikorsky CH-54 Tarhe. Although the concept of air mobility had been developed with a mid-intensity European conflict in mind, Army Aviation and the helicopter had proven themselves during the low intensity conflict in Southeast Asia.