U.S. Army handout file photo shows a CH-47F Chinook helicopter landing at Camp Marmal in Mazar-e Sharif province

A CH-47F Chinook helicopter with 1st Air Cavalry Brigade, 1st Cavalry Division, lands on the flight line after a maintenance test flight at Camp Marmal, in Mazar-e Sharif province, Afghanistan in this February 9, 2012 file photo by the U.S. Army. REUTERS/Felix Acevedo/U.S. Army/Handout via Reuters