Overview

CAP 437 is issued by the UK’s Civil Aviation Authority (CAA) and describes the standards for offshore helicopter landing areas. As such, it is considered worldwide to be a world leader in the field, and adherence to its regulations, even when not strictly required by local regulations, is considered best practice and paramount to operational safety of offshore helidecks.

The below is not necessarily meant to be extensive, but rather as a quick reference. Of course all IMT Helideck Lighting products comply with, and often exceed, all requirements as set by CAP437.

The below summarizes Chapter 4.3 (lighting) of CAP 437. Please click here to download a complete version of CAA CAP437.[MD1] 

A CAP437 compliant helideck would have to include:


 [MD1]Link to https://www.caa.co.uk/docs/33/CAP437.pdf

Touch-Down/Position Marking (TD/PM)

The purpose of the TD/PM Marking is to provide effective visual cues in order to both easily locate the helideck on the platform at long range during the approach, and to assist the pilot in positioning the helicopter during touchdown. The main system requirements are:

  • Light output: the required light output is quite complex and is described in Chapter 4.3 (for the Circle) and Chapter 5.3 (for the H) of Annex C to CAPP437. The light output should be verified by an accredited independent test house.
  • Height: <25 mm.
  • Any vertical edge greater than 6 mm should be chamfered to avoid becoming a trip hazard.
  • Where practical (so on non-illuminated surfaces) the friction coefficient should be greater than 0,65.
  • Mechanical strength: should be able to withstand a helicopter touching down. The force is defined as at least 1,655 kPa/m2 but ideally greater than 2,280 kPa/m2.
  • Explosion proof as required for the zone it is to be installed in.
  • Resistant to environmental influences (weather, chemicals, guano et cetera).
  • Temperature range: as appropriate for ambient conditions.
  • Ingress protection: at least IP66.

The IMT CIRCLE-H Helideck Lighting system  has the required light output (verified by Dekra, a widely recognized notified body), is certified for installation in hazardous areas (zone 1 & 2) to both ATEX and IECEx standards and for temperature ranges from -30 to + 55 °C, with an IP67 ingress protection. The light fitting, including mounting plate, measures 24,5 mm at its highest point and is made out of a sophisticated light alloy that is extremely corrosion resistant. Both extensive simulations and experience in the field indicate that the strength exceeds the ideally required 2,280 kPa/m2 requirement.

 

Helideck Status Light System (HSLS)

The purpose of the Helideck Status Light System is to warn a pilot of a condition that can be hazardous for the helicopter, its occupants or others. In essence, the Status Light tells the pilot not to land on the helideck. Such hazardous conditions can be a gas release (the gas could cause the engine to stall, while the hot exhaust could become an explosion hazard), a moving crane, obstructions or personnel on or near the deck, or any other hazardous conditions. The main system requirements are:

  • The system should be activated automatically in the event of a fire/gas alarm.
  • It should be possible to be activated manually by the HLO.
  • Light output: For Main lanterns at least 176 cd for all angles, 700 cd for 2-10°. For repeater lights at least 16 cd.
  • Quantity: Depending on the configuration and placement of the helideck. The number of main lights should be sufficient to ensure visibility from all angles of approach, and from all orientations on the deck of a landed helicopter.
  • Maximum height: 250 mm if installed in the obstacle free sector (or 5 cm if installed in the obstacle free sector on decks with a d-value of 16 m or less).
  • Frequency: 120 Hz for the system as seen by the pilot.
  • System should be dimmable to a maximum of 60 cd.
  • The system has to be activated and reach full output within 3 seconds.
  • The system has to be either tested regularly, be redundant, or self-monitoring.
  • The system has to be connected to the Uninterruptible Power Supply (UPS).

In addition, for Normally Unmanned installations (NUIs), some additional requirements should be taken into account:

  • It should be possible to reset the system, once activated, remotely. Where this is not possible or practical, the system should reset automatically after an appropriate period (30 minutes is suggested). Of course, if the hazardous condition still exists the system should reactivate immediately.
  • As regular testing is not possible on a NUI the system should be either redundant or self-monitoring.

In addition to meeting all CAP437 mandated requirements, the IMT Helideck Status Lights incorporate smart electronics which are in constant communication (including when the lantern is not activated) with the IMT Status Light Control Panel. Thus, the system tests itself ensuring the highest possible reliability and contributing significantly to increased operational safety of the installation.

Perimeters

Perimeter lights are used to indicate the periphery of the helicopter landing area. Main requirements are:

  • Light output: max 60 cd at any angle, minimum 30 cd 0-10°, minimum 15 cd 10-20° and minimum 3 cd 20-90° elevation.
  • Quantity: not spaced further than 3 meters apart on the white line delineating the perimeter. In case of square or rectangular decks at least 4 on each side, including each corner.
  • Maximum height: 25 cm for decks with a D-value of 16 meters or higher, 5 cm for smaller decks.

IMT Perimeters are in full compliance with the required light output. With a height of about 135 mm, they are well below the maximum of 250 mm for helidecks with a D-value greater than 16 m. In addition, IMT will soon launch a line of perimeters suitable for installation on helidecks with a D-value of 16 m or less.

Floodlights

Floodlights were required in earlier versions of CAP437 to provide visual cues to assist with the touchdown. However, the latest version of CAP437 (issued February 2013) requires a CIRCLE-H Helideck Lighting System to fulfill this function. Floodlighting is still encouraged as a back-up and to assist in operations such as refueling and passenger movements.

  • Light output: Xenon (or alternative with the same photometric specification), arranged such as to not dazzle the pilot.
  • Quantity: 4-6.
  • Maximum height: 25 cm for decks with a D-value of 16 meters or higher, 5 cm for smaller decks.

IMT offers a line of ILED floodlights with photometric qualities similar to Xenon, but with much higher life expectancy, lower power usage and less maintenance required. In addition, the light distribution of LED is much easier to control, resulting in much less glare which could potentially dazzle the pilot if floodlights are used instead of the CIRCLE-H Helideck Lighting System.

Illuminated Windsock

A wind direction indicator (windsock) should be provided and located so as to indicate the free stream wind conditions at the installation/vessel location. Main requirements are:

  • Illuminated for nigh use
  • Located in an area where it would not become a dominant obstacle and where it is not affected by turbulence.
  • Quantity: 1 or 2.

Obstruction Lights - Group A

Obstruction lights are intended to provide the helicopter pilot with visual information on the proximity and height of objects which are higher than the landing area and which are close to it or to the LOS boundary. Main requirements are:

  • Light Output: minimum 10 cd for angles between 0 and 30°
  • Quantity: depends on situation; on all crane booms, on obstructions that are higher than the landing area and in close proximity to the Limited Obstacle Sector boundary. If these obstructions are taller than 15 meters, obstruction lights should be fitted at 10 meter intervals.

Obstruction Lights - Group B

An omni-directional low intensity steady red obstruction light should be fitted to the highest point of the installation. Main requirements are:

  • Light Output: minimum 50 cd for angles between 0 and 15° with a minimum of 200 cd for angles between 5-8°
  • Quantity: 1, fitted on the highest point of the installation. In case of Jack-Ups, additionally, 1 on each leg.

IMT offers several options that are fully compliant with the required light output.