Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The UH-60 Black Hawk is a four-bladed, twin-engine, medium-lift utility helicopter manufactured by Sikorsky Aircraft. Sikorsky submitted the S-70 design for the United States Army''s Utility Tactical Transport Aircraft System (UTTAS) competition in 1972. The Army designated the prototype as the YUH-60A and selected the Black Hawk as the winner of the program in 1976, after a fly-off competition with the Boeing Vertol YUH-61. The UH-60A entered service with the Army in 1979, to replace the UH-1 Iroquois as the Army''s tactical transport helicopter.