PENSACOLA, Fla. (AP) – Military officials say the salvage of a Black Hawk helicopter that crashed into the waters off Florida could begin Friday afternoon.

Four Louisiana National Guard soldiers and seven Marines were killed when the aircraft slammed into the water during a routine training mission in dense fog Tuesday.

The Air Force says in a news release that a salvage barge was expected to arrive at the crash site by early Friday afternoon. The work to haul the shattered helicopter core from about 25 feet of water could take up to eight hours.

A Coast Guard dive team is expected to help with the operation.

Officials say the salvage and recovery will end if weather conditions deteriorate. Sporadic rain showers covered the crash site on Friday, but the heavy fog that has hampered recovery operations since Tuesday lifted.