Overview
CAP 437, published by the UK Civil Aviation Authority (CAA), defines the standards for the design, operation, and safety of offshore helicopter landing areas. It covers helideck layout, lighting, obstacle clearance, meteorological instrumentation, and, where applicable, Helideck Monitoring Systems (HMS).
These standards apply to all UK-registered helicopters and offshore installations, including oil and gas platforms, floating production units, and offshore wind substations. On the UK Continental Shelf (UKCS), compliance with CAP 437 is recognised by the Health & Safety Executive (HSE) as evidence of conformity with offshore safety legislation.
Scope and Application
CAP 437 applies to both fixed and mobile offshore installations. Fixed helidecks, such as those on production platforms or substations, are evaluated primarily against design, lighting, and meteorological requirements.
For moving helidecks, such as those on semi-submersible rigs, FPSOs, and support vessels, CAP 437 also addresses motion and environmental monitoring. In these cases, the Helideck Certification Agency (HCA) provides detailed implementation guidance in its document “Standard Measuring Equipment for Helideck Monitoring Systems and Weather Data”, currently Revision 9c (2023).
Fixed vs Moving Helidecks
Although both categories fall under CAP 437, the distinction lies in their operational environment. Fixed helidecks remain stable relative to the sea surface and therefore do not require motion monitoring; meteorological measurements alone are sufficient.
Moving helidecks, however, experience pitch, roll, and vertical movement that directly affect helicopter performance. These installations must be equipped with a certified HMS that measures and reports deck motion and weather data in real time.
Relationship with ICAO Standards
CAP 437 builds on ICAO Annex 14, Volume II – Heliports, expanding its principles for offshore conditions. It introduces additional guidance on helideck geometry, lighting, obstacle protection, and environmental monitoring, making it the world’s most comprehensive offshore helideck standard.
International Recognition and Classification
Although developed in the UK, CAP 437 has become the international benchmark for offshore helicopter landing areas.
Classification societies, including ABS, DNV, Lloyd’s Register, and Bureau Veritas, typically specify CAP 437 as the minimum standard for helidecks on vessels and floating units when no local aviation regulation applies.
Some countries have implemented their own frameworks derived from CAP 437 principles. For instance, Norway regulates helidecks under BSL D 5-1 and relevant parts of BSL G 7-1, certified by CAA Norway; and Brazil applies NORMAM-223 (formerly NORMAM-27) through its maritime and aviation authorities. Both align technically with CAP 437’s intent and structure.
This broad international adoption has established CAP 437 as the de facto global best practice for helideck safety, meteorological accuracy, and monitoring performance.
Meteorological and Monitoring Requirements
A key element of CAP 437 is the provision of reliable meteorological data to support flight operations. Each helideck should supply accurate, locally measured information on wind speed and direction, air temperature, barometric pressure, visibility, cloud base, and current weather conditions.
For moving helidecks, this data is integrated within the HMS, which combines meteorological readings with deck-motion parameters such as pitch, roll, inclination, and significant heave rate. This ensures that pilots and offshore crews share a consistent, real-time picture of landing conditions.
Current Edition and HCA Implementation
The latest issue, CAP 437 Edition 9 (February 2023), consolidates recent updates to helideck lighting systems, repeater-light requirements, meteorological data accuracy, and HMS references.
It’s important to note that “Rev 9b” and “Rev 9c” refer to the HCA’s implementation standards, not revisions of CAP 437 itself. These documents explain how CAP 437 Edition 9 is applied to moving helidecks in practical terms.
WISE Group’s Commitment
At WISE Group, we design, deliver, and support Helideck Monitoring Systems and meteorological packages that fully comply with CAP 437 Edition 9 and HCA Revisions 9b and 9c.
Our systems are deployed worldwide across oil & gas, renewables, and marine sectors, providing dependable and compliant helideck operations.
We offer:
- Integration of HMS and weather systems
- Calibration, verification, and system upgrades
- Operator training and documentation
- Support for class-society approval and HCA audits
Through technical expertise and close alignment with international standards, WISE Group ensures each installation meets the latest requirements for helideck safety and operational excellence.
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