An EC-130H Compass Call flies a training mission over Lake Mead, Ariz. Compass Call is the designation for a modified version of the C-130 Hercules aircraft configured to perform tactical command, control and communications countermeasures. Specifically, the modified aircraft uses noise jamming to prevent communication or degrade the transfer of information essential to command and control of weapon systems and other resources. Modifications to the aircraft include an electronic countermeasures system, air refueling capability and associated navigation and communications systems. U.S. Air Force photo