 The Army convened a special task force under General Marks in January 1972 , to reevaluate the requirements for an attack helicopter . The purpose of the Marks Board was to develop an " updated and defensible " material needs document . The task force conducted flight evaluations of the AH @-@ 56 , along with two industry alternatives for comparison : the Bell 309 King Cobra and Sikorsky S @-@ 67 Blackhawk . Analysis of the three helicopters determined that the Bell and Sikorsky helicopters could not fulfill the Army 's requirements . 
