Three military air cargo planes with sophisticated firefighting equipment arrived in Ventura County on Tuesday to help battle the wildfires ravaging Southern California. Three more planes were also expected.

Modular Airborne FireFighting Systems, or MAFFS, sit inside the cargo bays of C-130 aircraft, carry 2,500 gallons of fire retardant and can spray a swath of land 100 feet wide and a quarter-mile long.

It's unclear which of the roughly 17 Southern California fires they will be sent to. Local firefighting officials make those decisions, said Rose Davis, a United States Forest Service spokeswoman at the National Interagency Fire Center in Boise, Idaho.

Ventura County Fire Department spokesman Capt. Barry Parker said Tuesday he had not been informed about the C-130s or whether they would be used to fight the Magic or Ranch fires.

"It's one of those things; until they get here, we can't count on them," Parker said of the aircraft.

Priority would likely be based on threats to structures, meaning areas like San Diego, Lake Arrowhead and Malibu may get the first nod, Parker said.

None of the planes is expected to leave the Channel Islands Air National Guard Station any sooner than 1 p.m. today, Major Bill Green said. Crews must first prepare a tanker facility for reloading retardant, he said.

The first of the C-130s, which flew from Colorado Springs, Colo., landed Tuesday at roughly 12:45 p.m. at the 146th Airlift Wing, said Lt. Col. George Cardwell, the wing's community manager. The Channel Islands base shares runways with Naval Base Ventura County at Point Mugu. A second plane from the Colorado base touched down about 45 minutes later.

The U.S. Forest Service operates the MAFFS in cooperation with the Air Force, Air National Guard and Air Force Reserve. The planes are kept at four Air National Guard bases.

A Charlotte, N.C.-based aircraft arrived about 3:30 p.m. The remaining aircraft — one more from North Carolina and two from Cheyenne, Wyo. — were expected by 6 p.m.

A pair of MAFFS also operate out of the 146th Airlift Wing at the Channel Islands base but are being refurbished, Davis said.

Gov. Arnold Schwarzenegger requested the C-130s from the Department of Defense on Monday.

On Tuesday, Schwarzenegger announced additional airborne firefighting resources, including helicopters, air tankers and two DC-7s.

The C-130s join other aircraft contracted by the Forest Service, including Lockheed P2Vs, which carry about 2,000 gallons of retardant, and Lockheed P3s, with 2,500 gallons, Davis said.

The MAFFS system is about 30 feet long, taking up all but 10 feet of the C-130's cargo bay. Five pressurized tanks with Forest Service logos hold fire retardant. Flying about 150 feet off the ground, the planes discharge the retardant in a billowy red jet stream from large silver tubes dangling out the rear cargo bay door.

Another plane flies ahead to map out the route and point out landmarks for C-130 crews.

The retardant is about 85 percent water and 15 percent chemicals, Davis said. Salts in the chemicals squelch oxygen from the fire. A gumlike thickener helps the chemicals stick to brush and other ground fuel, prolonging the effect, she said.

At least two of the six C-130s can dump two rounds of retardant per flight, while the four others must reload after each run, Davis said.

About 100 military personnel will fly and maintain the six aircraft, which will use the 146th Airlift Wing as an operations center, officials said.

An additional dozen Forest Service employees are expected to participate on the ground, Green said.

Green briefed about 30 military personnel from Colorado in the early afternoon Tuesday on local weather and roads.

"Hopefully, we'll cool things down and get this under control," Green told the group.