This is the piece of helideck equipment most likely to be new to a site, and it comes with a
deadline. Q-Aviation state that the HMS Repeater Light System will become mandatory for all
vessels, jack-up rigs and other moving platforms that follow CAP437 Revision 9. If a moving
structure with a helideck is working to CAP437, this moves from a good idea to a requirement.
The problem it solves is a real gap in how helideck motion has been handled. A helideck
monitoring system measures pitch, roll, heave and wind, and compares them against the operating
limits. Traditionally that assessment lived on a screen in the control room and reached the
aircraft by radio - which means the pilot's knowledge of whether the deck is inside limits
depends on a verbal relay, at the busiest moment of the flight, in the worst conditions. The
repeater light puts the HMS verdict on the deck itself, where the pilot can see it.
It does that with a combined red, amber and blue light. A three-state indication is the right
design for this: it distinguishes between within limits, marginal and outside limits, rather
than reducing a graduated condition to a yes or no. The pilot reads the deck's status directly
from the deck during the approach, and it updates as the motion does.
The system is supplied as a system rather than as lights. Q-Aviation describe it as four HMS
repeater lights, an on-deck junction box and a control cabinet that can be placed in the control
room. Four lights is what gives visibility from the approach directions a moving platform can
present, since a vessel's heading and therefore the aircraft's approach vary. The on-deck
junction box keeps deck wiring in one certified, accessible place, and putting the control
cabinet in the control room is what ties the lights to the HMS and to the people watching it.
Q-Aviation note it is designed to withstand the conditions of the offshore environment,
which for equipment mounted on the deck of a moving vessel means salt, impact, wash-down and
constant vibration. Because the requirement is tied to a specific CAP437 revision, the practical
advice is to establish which revision your operation is being assessed against before planning
the work - the upgrade involves deck penetrations and a control room cabinet, which is a
shutdown or a docking rather than an afternoon.
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