The deaths of the two-person flight crew killed in the crash of a UPS cargo plane in Birmingham, Alabama, have been ruled accidental, the local coroner reported Thursday.

Capt. Cerea Beal Jr. and First Officer Shanda Fanning died as a result of blunt force injuries from the crash of the Airbus A300, which slammed into an open field near the city's airport on August 14.

The National Transportation Safety Board is investigating the crash, and a preliminary probe found no signs of an uncontained engine failure or fire aboard the jet before it went down. The crew did not report any trouble before the crash, Birmingham Mayor William Bell told reporters.