Test Control. To the greatest extent possible, the test agency should not interferewith the test unit during OT; however, there are exceptions to this philosophy, most notably the need to balance test interference with data collection. The use of Observer/Controllers (OCs) during OT is one area where test team interference on test unit operations is acceptable. OCs could be used to influence test unit behavior to ensure that test objectives are met and to ensure that the test unit employs UAVs as envisionedby the Concept of Operations.