Description:

The aircraft was built from a UH-60A and identified as prototype M1.

Source: "Blackhawk: The Story of a World Class Helicopter", Ray D. Leoni, Published by American Institute of Aeronautics and Astronautics, 2007, ISBN-13: 978-1-56347-918-2, Page 235

This information is reprinted by permission of the American Institute of Aeronautics and Astronautics, Inc.