SPC/TECH/OSD/29
To make inspectors aware of changes to international helideck lighting standards which have recently been agreed, and the programme for their implementation.
1 Improvements to helideck lighting systems have recently been agreed by the International Civil Aviation Organisation (ICAO) and will be incorporated in updated guidance issued by the Civil Aviation Authority (CAA).
2 The CAA has written to bodies representing the UK offshore industry advising of the details of this updated guidance on offshore helideck lighting standards, describing the background to the initiative and setting out the associated changes to perimeter lighting and floodlighting. A copy of CAA's letter is reproduced as an Annex to this SPC.
3 The updated standards will address three main problems with existing helideck lighting systems:
4 The CAA intends to update CAP 437 - Offshore Helicopter Landing Areas: Guidance on Standards, 4th Edition (September 2002) in the near future and is encouraging the industry to implement the changes as soon as is practical. It has agreed with the industry that the changes proposed for CAP 437 will be implemented in two stages as follows:
Inspectors should note the contents of this SPC and the timescale for implementation of the helideck lighting system changes.
Civil Aviation Authority (CAA) - Offshore Helicopter Landing Areas: Guidance on Standards, 4th Edition (September 2002), ISBN 0 86039 741 6.
Further information can be obtained from OSD 4.8 Rose Court, (VPN 522 6553)
Safety regulation group
Flight Ops Inspectorate (Helicopters)
Offshore Helicopter Operators
Chief Executive UK Offshore Operators Association
BHAB Helidecks
Health and Safety Executive
Verification Agencies
British Rig Owners Association
International Maritime Contractors Association
International Association of Drilling Contractors
International Association of Geophysical Contractors
20 July 2004
Ref 10A/253/16/3
Dear Sirs
Helideck lighting - Further interim guidance on standards
1 Introduction
Further to my letter ref 10A/253/16/3 of 17 November 2003, ICAO has now endorsed the changes proposed to the helideck lighting standards contained in Annex 14 Vol.2. UK CAA, recommends that the improvements to helideck lighting systems be introduced in two stages and, in conjunction with other North Sea States, intends to update CAP 437 in the near future adding a recommendation that duty holders implement the first stage, Stage 1, as soon as practical.
The purpose of this letter is to update the interim guidance on offshore helideck lighting standards in respect of Stage 1 pending update of CAP 437, and supercedes the 17 November 2003 letter which should now be discarded. Section 2 describes the background to the initiative, and Sections 3 and 4 cover the associated changes to perimeter lighting and floodlighting respectively.
Three main problems exist with current helideck lighting systems:
CAA has consequently been researching improved lighting systems for offshore helidecks for a number of years. Work started in earnest with a series of three dedicated trials on the K14 platform in the southern North Sea. A conference paper describing the trials was presented at the Royal Aeronautical Society in London in March 2001. The full report on the trials has been published as CAA Paper 2004/01, and is available from the publications section of the CAA website. Since then, CAA has completed two dedicated trials at an onshore site just north of Aberdeen (Longside airfield) and a further four dedicated trials at Norwich airport to refine the system, test new ideas, and evaluate the effect of a landing net on the lighting. These trials are currently being written up and will be published in two separate CAA papers later in 2004.
As a result of this work, a proposal to change the standards and recommended practices in ICAO Annex 14 Vol.2 was made. This has been accepted and became effective for all member states on 12 July 2004 with a compliance date of 01 January 2009. Pending the mandate of the Annex 14 Vol.2 changes, CAA will update CAP 437 by including the associated material as additional information and encouraging the Industry to implement the new standards as soon as practical. CAA has agreed with UK Industry that these changes may be progressed in two stages. The changes proposed for CAP 437 will be implemented in these two stages as follows:
For Stage 1, the changes are now finalised and equipment to meet the revised specification is commercially available. It is therefore CAA's intention, in conjunction with other European States with offshore interests, to incorporate the Stage 1 changes as additional guidance material at the next update of CAP 437, scheduled for Autumn 2004.
As regards Stage 2, further trials are being completed to finalise the detail of the lighting and support the development of equipment suitable for installation on an offshore helideck. The associated changes will be considered for a further update of CAP 437 when this work has been completed.
In the longer term, the introduction of Stage 2 to offshore platforms is an issue that is likely to be raised as a topic for the 'new' UKOOA/CAA/Helicopter Operator forum. In particular, identifying a commercially available product and the priority of installing it onto platforms.
3 Perimeter Lights
3.1 General
CAA recommends implementing the new perimeter light specification at the earliest practical opportunity. This can most conveniently be accomplished on new decks or on existing decks during refurbishment where new lights are to be installed. Otherwise, some types of existing light can be modified (see Section 3.3) at reasonable cost to provide a satisfactory interim solution (until 31 December 2008) that represents a significant improvement over the current standard.
3.2 New Lights
Where new lights are to be purchased, it is recommended that these fully meet the new specification in terms of both colour and intensity. It is CAA's understanding that a number of suppliers have suitable products available.
The colour of the light shall be green as defined in ICAO Annex 14 Vol.1 Appendix 1, para. 2.1.1(c), i.e. the chromaticity shall be within the following boundaries:
Yellow boundary x = 0.36 - 0.08y
White boundary x = 0.65y
Blue boundary y = 0.39 - 0.171x
As regards intensity, the following change to Annex 14 Vol.2 has been adopted:
| Elevation | Intensity |
|---|---|
20º-90º |
3cd |
13º-20º |
8cd |
10º-13º |
15cd |
5º-10º |
30cd |
*2º-5º |
15cd |
-180 Azimuth +180
*Additional values may be required in the case of installations requiring identification by means of the lights at an elevation of less than 2.
Nb: The note below the table was inserted at ICAO with offshore helidecks specifically in mind; operational data from 270 night approaches to 50 different installations in the North Sea has confirmed the need for the beam to extend down to the horizontal.
CAA recognises that the form of presentation chosen by ICAO is designed to cover TLOF lighting systems for both offshore and onshore environments where specific operational requirements may differ. While fully accepting the ICAO standard in general, with the benefit of extensive research in relation to offshore operations the CAA recommends the enhanced specification for offshore helideck perimeter lights defined in the table below:
| Elevation | Intensity |
|---|---|
0º - 90º |
60cd max* |
>20º - 90º |
3cd min |
>10º - 20º |
15cd min |
0º -10º |
30cd min |
-180 Azimuth +180
Nb: A study of helideck lighting performed for the Dutch CAA by TNO Human Factors (report ref. TM-02-C003) has indicated that lighting intensities greater than 60cd can represent a source of glare. The value of 60cd has therefore been provisionally adopted as a maximum value, however, it is now likely that this value will be challenged and consequently adjusted upwards. For the time being it is recommended that duty holders apply this conservative upper intensity limit when purchasing helideck lighting equipment.
CAA recommends that any new perimeter lights designed for use offshore meet this enhanced intensity specification which, in any case, is compatible with the ICAO specification.
3.3 Existing Lights
Green filters are available for some existing perimeter lights at modest cost, and could be installed with relatively little effort. While CAA wishes to encourage platform operators to implement the colour change as soon as possible, the following issues need to be considered:
4 Floodlights
4.1 General
While the continued use of deck level floodlights is allowed under the new ICAO Annex 14 Vol.2 Phase 2 material, the current standard is difficult to meet and there is presently no practical means available of ensuring initial or continued compliance. It is considered that, by reducing the conspicuity of the pattern formed by the perimeter lights and in potentially presenting a significant source of glare, deck level floodlighting is often counter productive.
Under the newly adopted ICAO Annex 14 Vol.2 material, a lit touchdown marking and/or heliport identification marking may in future be used in lieu of floodlighting (Stage 2). Currently, CAA does not believe that any products are readily available that are suitable for use in the offshore environment. As an interim measure and where practical therefore, CAA recommends replacing the existing deck level floodlighting with a combination of high-mounted floodlights located within the Limited Obstacle Sector (LOS) and deck level floodlights on the opposite edge of the deck to the LOS. If the existing deck level floodlights are suitable for re-use as high-mounted (or LOS) floodlights, the cost of this modification is expected to be modest.
4.2 Improved Floodlighting System
The main constraining factor in floodlighting helidecks is the 25cm height limit within the 210 Obstacle Free Sector (OFS). With reference to Figure 3.1 in CAP 437, however, obstacles up to a height of 0.05D are permitted at the edge of the helideck within the 150 Limited Obstacle Sector (LOS). Trials conducted by CAA have demonstrated that useful light can be provided by using a minimum of two ORGA SHLF218 halogen units mounted at a height of 0.05D within the LOS, angled downwards by approximately 5 and fitted with louvres to prevent glare, together with two Tranberg TEF 9964 xenon floodlights mounted at deck level opposite the LOS.
Nb: The lighting products employed for CAA's trials are stated above in order to provide an indication of suitable beam characteristics. Alternative products with similar beam characteristics are equally acceptable. No product endorsement is either made or intended.
While not fully compliant with the ICAO Annex 14 Vol.2 standard, this system offers the following advantages:
This arrangement also provides general lighting for deck handling operations.
As stated above, correct louvre design for the high-mounted floodlights is essential to avoid glare and to minimise the attenuation of the main beam of the floodlights. CAA has included guidance material for the design of louvres for this application as an appendix to the Longside trials report (shortly to be published as a CAA paper). In the meantime, key louvre design parameters to note are:
Lighting equipment manufacturers may contact CAA directly for further information on louvre design pending publication of the Longside trials report.
In summary, pending availability of suitable hardware to implement Stage 2 of the helideck lighting improvement programme (lit yellow aiming circle and lit green 'H'), CAA recommends replacing existing deck level floodlighting systems with a combination of a minimum of two high mounted halogen floodlights supplemented with two xenon floodlights mounted around the helideck perimeter at deck level opposite the LOS high mounted units.
NB1 : High intensity xenon floodlights are not recommended for high-mounting within the LOS. The 5 angle of depression will result in reflections from the deck surface (when wet) into the approach path and unacceptable glare in certain approach directions.
NB2 : Halogen floodlight units are not recommended for deck level use. Their intensity is unlikely to provide sufficient illumination of the deck surface and the relative lack of close vertical beam control could result in glare in the event of misalignment unless fitted with suitable louvers (which would further reduce the output of the light).
4.3 Caveats
For helidecks located on platforms with a sufficiently high level of illumination from cultural lighting, the need for an improved floodlighting system may be reviewed with the helicopter operator(s), i.e. in such circumstances it may be sufficient to just delete or disable the existing deck level floodlighting. This concession assumes that the level of illumination from cultural lighting is also sufficiently high to facilitate deck operations such as movement of passengers and refueling (where applicable). It is a condition that prior to the removal of floodlights, extended trials of the 'no-floodlight' configuration be conducted and their subsequent removal will be subject to satisfactory reports from crews to indicate the acceptability of operating to the helideck with the re-configured lighting.
For helidecks that are currently obstacle free and/or for minimum sized helidecks (e.g. NUIs), it may not be desirable or practical to fit high-mounted floodlights within the LOS, i.e. to create an obstacle where there is presently none. In the absence of sufficient cultural lighting, CAA recommends that installation owners consider a deck level floodlighting system consisting of not less than 4 deck level xenon floodlights equally spaced around the perimeter of the helideck. In considering this solution, installation owners must ensure that the deck level xenon units do not adversely effect the pilots' judgment by ensuring that they do not present a source of glare or loss of pilots' night vision on the helideck, and do not affect the ability of the pilots to determine the actual location of the helideck on the installation. It is therefore essential that all lights are maintained in correct alignment. It is also desirable to position the lights such that no light is pointing directly away from the prevailing wind. Floodlights located on the upwind (for the prevailing wind direction) side of the deck should ideally be mounted so that the centerline of the floodlight beam is at an angle of 45 to the reciprocal of the prevailing wind direction. This will minimise any glare or disruption to the pattern formed by the green perimeter lights for the majority of approaches. An example of an acceptable floodlighting arrangement is shown at Figure 1 .
For NUI's previously fitted with deck mounted halogen systems but now fitted either with the improved floodlighting system recommended in Section 4.2 or the 4 deck level xenon units as described above, it would be desirable to redeploy surplus halogen units to improve illumination of the platform structure below deck level. This will assist to alleviate the 'floating in space' effect often encountered with operations to NUIs which have no other significant sources of cultural lighting.
For helidecks on mobile installations where deletion of the deck level floodlighting is appropriate, it may be desirable to disable the existing floodlighting rather than remove it. Adoption of this solution would facilitate the re-instatement of the deck level floodlighting should the installation move out of the UKCS into a region where strict adherence to the letter of the ICAO requirements for floodlighting is necessary.
Yours faithfully
Kevin P Payne
Flight Operations Inspectorate (Helicopters)
CC: International Association of Oil and Gas Producers
Maritime and Coastguard Agency
Offshore Contractors Association
Cogent/ Offshore Petroleum Industry Training Organisation
Civil Aviation Authorities of Norway, Denmark, Ireland and Netherlands
Helideck Lighting Manufacturers
