Air Force Chief of Staff Gen. Mark Welsh said Friday that he expects a spirited debate over the possibility of eliminating the service’s fleet of aging A-10 Warthogs but said the move would be required to contend with the tightened budget environment. Welsh played down the notion that getting rid of the A-10s would significantly diminish the Air Force’s ability to provide close air support for ground troops--the primary role of the aircraft. He said other planes like the F-15,…