FARGO - After two failed tries, the first unmanned aircraft system to patrol the northern U.S. border successfully completed its flight from Arizona to North Dakota.

U.S Customs and Border Protection officials said the Predator B drone touched down at 2:28 p.m. Saturday at the Grand Forks Air Force Base, after a six-hour flight from Libby Army Airfield in Sierra Vista, Ariz.

"It was a great day, actually, from takeoff to landing," said Michael Corcoran, deputy director for air operations for U.S. Customs and Border Protection's Air and Marine office in Grand Forks. "It was a great flight."

Earlier landings Thursday and Friday were postponed due to maintenance problems and the weather. Corcoran said customs and border officials were anxious for the arrival, but weren't frustrated by the delays.

"We're certainly glad to have it here," he said.

The Predator weighs 5 tons, has a 66-foot wingspan and can fly undetected at altitudes of up to 50,000 feet. It can fly for up to 28 hours at a time, and will be equipped with sensors and radar.

The drone has been in use along the southern border with Mexico since 2005. Corcoran said the plane has been successfully tested in cold weather, as well.

"Now that we'll have the opportunity to use it in a daily basis in the winter, we can only learn from that and get better every day," he said.

The drone, which can be flown from various sites, including Grand Forks, is scheduled to begin patrolling the border in January. Officials are waiting for clearance on air space before deciding on a schedule, Corcoran said.

Sen. Kent Conrad, D-N.D., said the state's congressional delegation has been working for four years to get the unmanned aircraft to North Dakota.

"It is vital to America's security that we protect our borders, particularly the northern border," Conrad said. "The Grand Forks Air Branch plays an essential role in helping shut the door on terrorists who want to sneak across remote border points to strike on U.S. soil."

Corcoran said a "dull roar" of cheers could be heard across the airfield when the plane landed.

"The aviators all brag about the perfect landing. I guess we'll brag about this one, as well," he said.