Radar assistance to aircraft with radiocommunications failure
When a controller suspects that an aircraft is able to receive but not transmit messages, the radar may be used to confirm that the pilot has received instructions.
OO-ABC REPLY NOT RECEIVED IF YOU READ GREENVILLE CONTROL TURN LEFT HEADING 040
FASTFLY 123 REPLY NOT RECEIVED IF YOU READ GREENVILLE CONTROL SQUAWK IDENT
FASTFLY 123 SQUAWK OBSERVED POSITION 4 MILES NORTH OF TENTOWN VOR I WILL VECTOR YOU TO THE FINAL APPROACH RUNWAY 18