Saint Jack
i.e. "....RED light don't land..." Already done, see CAP437, Chap. 4 Para. 3.6
From CAP 437
A visual warning system should be installed if a condition can exist on an installation which may be hazardous for the helicopter or its occupants. The system (Status Lights) should be a flashing red light (or lights), visible to the pilot from any direction of approach and on any landing heading.
You are mixing up 2 different circumstances. The Red flashing status lights indicate an unsafe condition on the rig ie gas release. They are usually triggered automatically when such an unsafe condition exists. They are NOT used to indicate that the deck is unavailable due to the lack of HLO/firecover.
The helideck edge lights are now green in the NS so as Impress to inflate proposes a simple switch to red would indicate the deck is closed. Easy to see in the dark and usable in bright daylight.
HF