Originally Posted by
Pltnorway
That is a very valid question.
With the radar set to 10 NM range on the PM's (copilot) NAV screen in this case, the waypoint symbol for "BLKMO" would hide the radar return from Blackrock. If using 5 NM, or even better 2.5 NM range, the return from Blackrock would be relatively larger than the waypoint symbol, and hence get your attention.
I tried this a couple of days ago (in the S92 with the Primus 701A radar) using an oil rig as "Blackrock". With 10 NM range, GMAP2, optimal gain and tilt, and at a distance of 1-2 NM from the oil rig it was very difficult to actually spot the return because of the waypoint symbol. Blackrock might have given a slightly larger return than an oil rig though.
The more I think about it, the more I think overlay technology for radar wherever radar is the primary mechanism for obstacle avoidance ought to be officially SOP'd out of existence as of right now. And given the inherent weaknesses of SOPs as quoted by TREs on this and other threads then I think a technology solution (dedicated screen?) may be required.