Originally Posted by
chevvron
ATC are entitled to assume the codes for pipeline helis and police have already been validated and their altitude readout verified by the unit they were working previously; I would assume they want controllers to assign a discrete code to aircraft previously using a conspicuity code to show other units the aircraft is actually talking to an ATC unit rather than just listening out.
So who has validated and verified the pipeline helicopter that departs from a non-surveillance equipped AFIS or A/G airfield in class G airspace then?