An Air Force staff sergeant is missing after falling about 1,500 feet from a plane during a training exercise over the Gulf of Mexico in Florida this week, according to new reports.

The airman was training around 1:45 p.m. Tuesday when he plunged out of the C-130 aircraft and into the water, the US Coast Guard told local station WEAR.

Others on the plane saw the airman’s parachute deploy and reported that he was treading water, according to the Coast Guard.

When the C-130 made a turn to pick him up, they lost sight of him, officials said.

The airman exited the plane about four miles south of the 24th Special Operations Wing at Hurlburt Field, Florida, officials from the wing told the Air Force Times.

The Coast Guard, as well as the Florida Fish and Wildlife Conservation Commission, have assisted the Air Force in their search about a mile and a half south of Florida’s Santa Rosa Island, WKRG reported.

The airman was not immediately identified.