Unmanned U.S. aircraft plunges into Pacific

U.S. Customs and Border Protection grounded its fleet of unmanned aircraft Tuesday after losing one worth $12 million in the Pacific Ocean.

The unarmed aircraft had a mechanical failure while on patrol of the southern California coast.

The crew determined that it wouldn't make it back to Sierra Vista, Ariz., "and put the aircraft down in the water," the agency said in a statement.

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