Marine killed Tuesday has been identified

Sgt. Matthew Bylski, assigned to Battalion Landing Team 1/5, 15th Marine Expeditionary Unit, was the vehicle commander of the ACV that rolled over during training at Camp Pendleton, Calif., according to a statement from I Marine Expeditionary Force.

"Words fail to express our sorrow at the tragic loss of Sgt. Bylski; an outstanding Marine and a leader within his platoon," Col. Sean Dynan, commanding officer of the 15th MEU. "The MEU – the Marines who lived, trained, and learned from Sgt. Bylski, mourns alongside his family and friends. The entire 15th MEU 'Vanguard' family is affected by his absence."

Of the 14 other Marines who were aboard the ACV during the accident, one remains hospitalized in good condition, I MEF announced.

The incident is under investigation.

According to I MEF, "Bylski joined the Marine Corps in January 2019. His awards and decorations include two Navy and Marine Corps Achievement Medals, Navy Meritorious Unit Commendation, Marine Corps Good Conduct Medal, National Defense Service Medal, Global War on Terrorism Service Medal, and Sea Service Deployment Ribbon."

The 15th MEU is set to be the first unit to deploy with the ACV, the service's long-awaited replacement to the decades-old AAV.

The MEU has been training in Southern California for a deployment with the Boxer Amphibious Ready Group. The 15th MEU includes the command element, Battalion Landing Team 1st Battalion, 5th Marines, Combat Logistics Battalion 15, and Marine Medium Tiltrotor Squadron 165 (Reinforced). The 15th MEU has been doing integrated training with the San Diego-based ARG that includes the big-deck assault ship USS Boxer (LHD-4), amphibious transport dock USS Somerset (LPD-25) and amphibious dock landing ship USS Harpers Ferry (LSD-49).

The first deployment of the ACV has been delayed since 2022 following incidents where the amphibious connector rolled over in heavy surf. Since then, the Marines have created a new schoolhouse to improve ACV operations.