WASHINGTON: An unmanned US spy plane crashed in Pakistan on Wednesday, US officials said. The officials, speaking on condition of anonymity, said the cause appeared to be engine failure rather than hostile fire. It was the second Global Hawk aircraft to crash since the war in Afghanistan began last October. The first, in late December, went down in an undisclosed country near Afghanistan. The Air Force said last week that an accident investigation pinpointed structural failure as the cause of that crash. The investigators traced the problem to an improperly installed bolt that caused a control rod to fail. The...