I had a hawk come pretty close but not dangerously so last Thursday while I was clattering from Plymouth to Truro in my R44. Same height, heading South to play with the ships in the danger areas in the English channel - it was "Thursday war" as usual.
Some questions:
What kind of radar do they have on board?
Can they see my transponder?
Or is collision avoidance simply left to the good old Mk1 eyeball and lightning reflexes?
SB