Conclusions (A Preliminary Study of Unidentified Targets Observed on Air Traffic Control Radars)

  1. It is believed that most of the unidentified targets observed on the Washington MEW radar during the period beginning on the night of August 13, 1952 and the period beginning on the night of August 15, 1952 were ground returns caused by reflection phenomena closely connected with the temperature inversions in the lower atmosphere.
  2. Unidentified radar targets of the type described in this report have been noticed since the early days of radar. Unusual weather conditions prevailing in the Washington area during the summer of 1952 were exceptionally conducive to the formation of these phenomena.
  3. Present evidence indicates that the appearance of unidentified targets of this nature on radar scopes has but little effect on the control of air traffic. At its worst, it forms a nuisance by cluttering the scope display and by requiring that additional traffic information or heading instructions be issued in order to protect other traffic against the possibility that such a target might be a helicopter.
  4. In some cases, it would be desirable to provide the controller with a more positive method of identifying targets such as these so that he could determine quickly whether they are spurious or whether they are actual aircraft.