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Helideck Systems
Helideck Systems covers the offshore landing area and what is fitted to it: steel or aluminium deck structures, green perimeter lights, the lit touchdown and positioning circle and H, status lights, floodlights, landing nets, wind indicators and helideck monitoring systems (HMS). A used helideck is judged on the D-value and t-value it was certified for and on the CAP 437 edition its lighting and motion system meet.
How a helideck works
The deck plate carries the landing loads of the design helicopter into support steel tied to the hull or jacket. Its surface must give enough friction for a helicopter to sit on a wet, moving deck without sliding. A gutter and drains round the edge carry fuel and fire water away.
The lighting tells the pilot where the deck is and where to put the wheels.
- Green perimeter lights mark the edge of the landing area, spaced no more than 3 m apart.
- A yellow lit touchdown and positioning (TD/PM) circle and a green lit H give the visual cue on short final.
- Red flashing status lights warn the crew not to land when the deck is unsafe.
- Floodlights light the deck for passengers and refuelling, and should be switched off during all helicopter movements.
On a floating unit, the HMS measures pitch, roll, inclination and significant heave rate. The radio operator passes those values to the crew, who check them against limits for their aircraft before they land.
Configurations
| Type | Where it fits | Main concern on a used unit |
|---|---|---|
| Welded steel plate deck | Integral to a jacket or hull | Corrosion at gutters and stiffeners |
| Extruded aluminium deck | Bolted onto a steel support frame | Galvanic corrosion at the steel joints |
| Passive fire-retarding surface | Perforated aluminium deck | Blocked perforations and drainage |
| Fixed versus moving deck | Platform or floating unit | Moving decks need an HMS and higher friction |
Key specifications
| Parameter | Why it matters | Typical classes or units |
|---|---|---|
| D-value | Sets deck size, sectors and lighting layout | Metres |
| t-value | Sets the structural rating | Tonnes, maximum take-off mass |
| Surface friction | Stops a helicopter sliding on a wet or moving deck | Average friction coefficient (µ) |
| Lighting scheme | Decides whether night flights are allowed | Perimeter only, or perimeter with TD/PM circle and H |
| HMS revision | Decides acceptance by the helicopter contractor | HCA standard revision number |
| Supply | Lighting and HMS power and UPS | Volts, hertz, UPS minutes |
Standards and certification
CAP 437 and ICAO Annex 14 Volume II set the deck size, markings, lighting, friction and obstacle rules. The lighting must meet the photometric and colour requirements in CAP 437, so ask for the manufacturer's test evidence. On the UK continental shelf, the Helideck Certification Agency (HCA) inspects each deck and issues its certificate. A mobile unit may also carry a class notation such as DNV HELDK. None of these certificates follows the deck to a new unit.
Failure modes and inspection
- Friction. Coatings and grit wear smooth, and contamination cuts friction further. CAP 437 sets a minimum average of 0.6 inside the TD/PM circle on a fixed deck, 0.65 on a moving deck and 0.5 elsewhere. A deck is normally re-tested every year and after any remedial work, or every two years if every area beats its minimum by at least 0.1.
- Structure. Look for corrosion at gutters, drain boxes and support connections, and for cracks at aluminium extrusion joints. Use ultrasonic thickness readings and magnetic particle or eddy current testing on welds.
- Lighting. Check for water in fittings, failed LED drivers, crushed TD/PM segments and cable damage at the deck edge.
- HMS. Check the motion sensor's calibration date and that the display and radio link work.
- Nets. CAP 437 now treats a net as a fix for poor friction, not a default fitting, and rules it out with a deck-integrated foam system on a solid plate deck.
Documentation
- Structural design calculations for the rated t-value
- As-built drawings, including the support steel interface
- Last helideck inspection report and certificate
- Latest friction survey with the test method and date
- Lighting certificates of conformity and photometric test evidence
- HMS revision, software version and sensor calibration certificate
Integration and compatibility
Check the deck against the receiving structure's support points and the obstacle sectors around it. Lighting needs a helideck control panel, UPS and cabling routed to the landing area. The HMS needs input from a motion reference unit and a link to the radio room. Fire cover comes from helideck foam systems, which may use nozzles set into the deck itself.
Refurbishment and recertification
A used aluminium deck can go onto new support steel if its D-value and t-value suit your helicopter. Plan for a new friction coating or grit surface, a friction test and replacement of tired lighting fittings. Floodlight-only decks need a TD/PM circle and H set before UK night flights. The installed deck then needs its own helideck inspection and certificate.
FAQ
Frequently asked questions
What lighting does a CAP 437 helideck need?
A CAP 437 helideck needs green perimeter lights, a lit yellow touchdown and positioning circle, a lit green H and red flashing status lights. Floodlights may light the deck for passengers and refuelling but must be off while a helicopter approaches, lands or takes off. Floodlight-only decks no longer allow night flights on the UK continental shelf.
Is a landing net still required on a helideck?
No, CAP 437 no longer treats a landing net as a default fitting. A net is a way to deal with low surface friction, and only on a deck that still reaches the minimum friction outside the net. CAP 437 also rules out a net on a solid plate deck fitted with a deck-integrated foam system.
Does a used helideck need a new friction test?
Yes, test the friction after the used deck is installed and before the first landing. Coatings degrade in storage and transport, and the minimum values differ between fixed and moving decks. CAP 437 expects a re-test every year and after any remedial work, so an old survey from another unit will not count.
What does a helideck monitoring system measure?
A helideck monitoring system measures the deck's pitch, roll, inclination and significant heave rate on a floating unit. The radio operator reports these values to the helicopter crew, who compare them with their aircraft's limits. In UK waters it must meet Rev. 9 or later of the Helideck Certification Agency standard, and Rev. 9c from 1 October 2025. Also check the sensor's calibration date.
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