(Editor's note: This story has been updated to reflect that delivery of the first Super Tucano aircraft to the Afghan air force is scheduled for April 2014, and not 2015 as originally reported.) The Air Force has awarded Sierra Nevada Corp. a $427.5 million contract to provide 20 light-attack aircraft to the Afghan military, the service announced today. The contract, covering the Light Air Support program, increased by more than $72 million from when it was first awarded, and...