Marine Corps Training Command Cans Colonel in California

January 12, 2023Carl Prine
Marine Corps

On Wednesday, Jan. 11, 2023, the US Marine Corps announced Col. John L. Medeiros Jr. had been relieved from duty as the commanding officer of the California-based Assault Amphibian School. Coffee or Die Magazine composite.

A training accident in the California surf three months ago triggered the Marine Corps to can the colonel in charge of the its Assault Amphibian School.

Brig. Gen. Farrell J. Sullivan, the one-star in charge of Training Command, fired Col. John L. Medeiros Jr. on Monday, Jan. 9, due to a loss of trust and confidence in his ability to lead the school, according to a statement released by the Corps on Wednesday.

The relief of Medeiros is tied to what officials claim is an ongoing probe into an Oct. 13 mishap involving an Amphibious Combat Vehicle off Camp Pendleton. At the time, the Corps alleged that an unspecified “mechanical malfunction” caused the ACV to roll over in the surf.

That sparked new rules that banned the 90 ACVs fielded by the California-based 3rd Assault Amphibian Battalion and the 36 carriers at Medeiros’ school from operating in rough surf areas near beaches. But they could still transit open ocean and protected waters, such as the Del Mar Boat Base at Camp Pendleton’s Area 21. 

Marine Corps

US Marine Corps Col. John Medeiros Jr, then-commanding officer of Assault Amphibian School, addressed the troops and their family members at the 5th Annual Thanksgiving Day and Service event on Nov. 18, 2021. US Marine Corps photo by Staff Sgt. Andrew Harris.

Coffee or Die Magazine’s attempts to reach Col. Medeiros to get his side of the story were unsuccessful. A cell phone number and personal email address in his name appear to have been recently discontinued.

Training Command officials contacted by Coffee or Die declined to elaborate on the colonel's termination.

It remains unclear where Medeiros has been reassigned or whether his firing is related to previous problems bedeviling the ACV program.

Before the surf ban, the armored carriers had just been greenlighted to return to sea duty on Sept. 22 — eight weeks after a pair of the vehicles foundered in high surf off Camp Pendleton — but only if certain weather conditions were met. 

Amphibious Combat Vehicle

US Marines with Amphibious Vehicle Test Branch, Marine Corps Tactical Systems Support Activity, drive a new Amphibious Combat Vehicle along the beach during low-light surf transit testing at Marine Corps Base Camp Pendleton, California, Dec. 18, 2019. The ACV is an eight-wheeled armored personnel carrier designed to fully replace the Corps’ aging fleet of Amphibious Assault Vehicles. US Marine Corps photo by Lance Cpl. Andrew Cortez.

ACVs still weren’t supposed to operate offshore when waves reached a breaker height of 4 feet. Officials haven’t said whether the ACV that flipped in the surf on Oct. 13 was cutting through waves that high, or how Medeiros was tied to the mishap.

Built by BAE Systems, ACVs are supposed to operate in conditions up to Sea State 3 — slightly rough waves cresting up to 4 feet high in open water — while bringing 13 troops and three crew members to shore, even through 9-foot plunging surf.

The ACVs are slated to replace an aging and increasingly dilapidated fleet of Assault Amphibious Vehicles, workhorse troop carriers that were designed during the Vietnam War.

“The Marine Corps continues to prioritize providing a safe and standardized training environment for Marines to gain experience with the ACV during this critical service-wide transition from the AAV,” the Training Command release stated. 

marine amphibious combat vehicle

US Marines and sailors with Charlie Company, 3d Assault Amphibian Battalion, 1st Marine Division, launch an amphibious combat vehicle into the water during a training event at Marine Corps Base Camp Pendleton, California, Jan. 31, 2022. US Marine Corps photo by Cpl. Alexandra Munoz.

A highly decorated Marine with nearly 27 years of service to the Corps, Col. Medeiros’ awards include the Defense Meritorious Service Medal, Meritorious Service Medal, Joint Service Commendation Medal, Navy and Marine Corps Commendation Medal with Gold Star and a "V" device for combat valor.

A veteran of the wars in Iraq and Afghanistan, he previously commanded 2nd Assault Amphibian Battalion.

Medeiros took the helm of Assault Amphibian School in mid-2021.

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Carl Prine
Carl Prine

Carl Prine is a former senior editor at Coffee or Die Magazine. He has worked at Navy Times, The San Diego Union-Tribune, and Pittsburgh Tribune-Review. He served in the Marine Corps and the Pennsylvania Army National Guard. His awards include the Joseph Galloway Award for Distinguished Reporting on the military, a first prize from Investigative Reporters & Editors, and the Combat Infantryman Badge.

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