Marines Launch New Probe into Fatal AAV Accident as Families Demand Accountability Marines aboard an amphibious assault vehicle exit the well deck of the amphibious assault ship USS Bataan (LHD 5 (U.S. Navy/Mass Communication Specialist 1st Class RJ Stratchko) 6 Apr 2021 For the second time in two years, the Marine Corps is reviewing the lead-up to a fatal accident -- a move that could leave more senior leaders facing fallout over a series of failures that led to nine troops losing their lives. Assistant Commandant Gen. Gary Thomas on April 2 directed Lt. Gen. Carl Mundy III to serve as president of a new investigation into the way the 15th Marine Expeditionary Unit assembled for its fall deployment last year. Eight Marines and a sailor assigned to that unit were killed during a July pre-deployment training exercise when their amphibious assault vehicle sank off California's coast.