撞船坠机，美军事故连环上演

Group 1 - The U.S. Navy is facing multiple incidents, including a fire on the "New Orleans" amphibious dock landing ship and two recent collisions involving unmanned vessels, raising concerns about the future of its unmanned fleet [1][2] - A recent crash of an F/A-18E Super Hornet during routine training marks the fourth loss of this aircraft type in the past year for the U.S. Navy [1] - The U.S. military is experiencing setbacks in developing autonomous unmanned vessels, with recent incidents attributed to software failures and human errors during testing [2] Group 2 - The U.S. Navy's procurement processes are being affected by personnel changes, including the dismissal of the head of the unmanned and small combat vessels program office [3] - Following the recent testing accidents, the Department of Defense has indefinitely suspended a $20 million contract with L3 Harris Technologies, a provider of unmanned vessel control software [3]