ABOARD THE USS BONHOMME RICHARD -- Within minutes of each other, helicopters swooped in to drop off Marines returning from an inland mission, and a Harrier jet lifted straight off the deck of this massive warship and blasted off toward a target somewhere near Yuma.

It was all part of an elaborate war game involving several ships and some 6,000 Marines and sailors of the Expeditionary Strike Group Five, which includes Camp Pendleton's 3,000 strong 15th Marine Expeditionary Group.

The action centered around the USS Bonhomme Richard in the waters off of Camp Pendleton, which is the flagship of the seven-vessel fleet that commanders said will embark by January for six months at sea and could possibly be headed to Iraq.

The 844-foot amphibious assault ship carries about 1,200 sailors and some 1,800 Marines. Officials said it serves as the strike group's command center and as a floating runway for a squadron of Harrier jets and helicopters.

"The tempo is definitely high and there is a real seriousness about it all," Gunnery Sgt. Robert Knoll, a spokesman for the Marines on board, said Sunday of the nearly three-week exercise.

In the corridor around him sailors rushed by, grabbing brightly colored survival vests that inflate if they are knocked off the deck by the blasts from Harrier jets or the wash of the massive choppers' blades.

Just outside, the flight deck buzzed with activity as two CH-46 helicopters touched down just long enough to let out a couple dozen Marines who scampered out from beneath the beating rotors carrying stretchers and medical bags along with their rifles and rucksacks.

The troops were returning from a "mass-casualty" drill somewhere deep inside Camp Pendleton, officers said.

One by one, three Harrier jets turned their noses toward the bow, tilted back a bit and blasted off down the runway.

A third one rose straight up and hovered in the air for a second at the edge of the ship before it shot off like a rocket to conduct a "deep strike" some 250 miles away in southern Arizona. The hover ability is a unique feature of the Harrier, a plane that commanders said gives the strike group its long-range punch.

Marine Col. Thomas Greenwood, the commander of the Marine force, said his troops have been on nonstop, overlapping missions for two weeks, conducting everything from conventional beach landings aboard air-cushioned landing craft near Camp Pendleton to a long-range air assault mission near San Francisco.

During the latter mission, specially trained Marines parachuted in from a C-130 transporter to scout a target area before other infantrymen raided the site during the night, storming in by helicopters that had to be refueled at temporary refueling points set up covertly along the way.

Navy Capt. Scott Jones, the ship's skipper, said the group has also been practicing such diverse missions as submarine warfare, humanitarian aid and embassy evacuations.

In addition to the USS Bonhomme Richard and the Marines, the strike group includes another smaller amphibious carrier, a cruiser, a destroyer, a frigate, a Coast Guard cutter and a submarine.

Rear Adm. Christopher Ames, the commander of Expeditionary Strike Group Five, said the force was specifically designed to meet the demands of the global war on terror.

"The range of capabilities we have is stunning," Ames said from the ship's Joint Operations Center Sunday.

The darkened room was filled with sailors busily plotting coordinates on charts and watching colored blips on radar screens as they tracked other ships, scoured the sky and planned the next operation.

"At any moment there is a hot spot in the world, this is the unit to which the Navy will turn," he said.

As the helicopters and jets touched down and took off from the deck for more training, Marines leaned over the rails of the "Vultures' Row," a small observation deck near the bridge, to watch the launch.

Petty Officer Glenn Owens, 28, of Youngstown, Ohio, was the sailor who controlled the activity on the flight deck Sunday.

Off the deck for a moment's break, Owens said the Marines and sailors aboard the Bonhomme Richard were taking this "day-in, day-out" training seriously as they eye events in Iraq.

After their scheduled return to port on Friday, the Marines and sailors are set to return to sea in early November for their last practice run before a six-month deployment at sea, which Jones and Greenwood said could include a mission to Iraq.

"On this one (deployment) you pretty much know you are going somewhere," Owens said Sunday. "So you might as well train like you mean it."

Contact staff writer Darrin Mortenson at (760) 740-5442 or dmortenson@nctimes.com.