HC makes a good point re power margins to compensate for heave, but I am asking you again, what technology, procedures or equipment do you need, based on a scientific approach to allow you to conduct Bow Deck landings at night?
Asked and answered.
I find it strange that we would direct attention towards something which has not caused accidents rather than to something which has, ie. CFIT, should we have dual EGPWS and a double AVAD instead?
HC will hopefully chip in here as it is a while since I flew EGPWS. However, onshore I cannot remember getting any warnings while flying instrument procedures. I suspect if they did get one on the localiser it would have been too late to do anything.
As to the AVAD, unless they had suspended it before becoming visual (unlikely) or it was u/s they would have probably got a shout at 200 and 100 feet and yet they still hit the ground/sea.
As to offshore approaches, you occasionally get 'Caution Obstacle' or 'Warning Obstacle' shouts as you approach a rig. If you are visual you can disregard these and continue the approach, which would have been the situation in the ETAP incident.
As to your comment about directing attention to things that have caused accidents, one would hope that any safety review worth the paper it is written on would address itself to not only factors that have caused accidents (the normal reactive approach) but factors which they think may cause accidents (proactive approach).