Thanks Gents,
I have heard the problem is more likely to arise when there are many installations in close proximity. The correct deck is cleared, and the landing is authorised, but when the heli lands, there's no-one there.... uh oh, should have been 1 mile over there...at that deck.
Overflying would seem to allow for a bullet-proof ID of the deck, but I guess you dont always overfly ..? More often it would be a straight in approach?
We can produce a unit to assist the pilots, but if there's no REAL problem, there wont be a market. I'm just trying to research that, and appreciate your feedback..
All experience and comment is welcome.