fire-control operator

air traffic control operator

control tower operator

operator control unit (OCU)

control post operator

vertical control operator

dual operator control

aircraft control and warning operator

individual control (of fire) / individual fire control

fire-control director / fire control director

fire control orders (FCO) ('Hold Fire', 'Cease Fire' and 'Engage')

slant fire; diagonal fire; oblique fire; fire to the oblique

early warning system (EWS) operator

identification operator

operator maintenance

operator’s pack

operator's permit

ship operator

telephone operator

radio telephone operator (RTO)

aiming rule operator

azimuth (deflection) display board operator

navigator-radio operator

air operator certificate

aircraft operator

airport operator

flight operator

flight radio operator

flight systems operator

operator  D / Dt

operator communication

radar operator

traffic operator