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Offshore Rig Helideck Lighting - Advances in Lighting at the Forefront of Aviation Safety

Published: 10th Nov 2010

While nobody would argue that aviation safety includes PPE, a worker’s primary means of transportation to and from work, or the means of bringing him the tools of his trade, or his food, is something he can reasonably expect to be run and maintained to the highest possible safety standards.

Safety is very important to everybody involved in offshore helicopter operations and, as a result of the disappointing safety record in the North Sea during the 1970s and early ‘80s, a major joint industry safety review was conducted. This exercise was led by the aviation safety regulator, the UK Civil Aviation Authority’s (CAA’s) Safety Regulation Group (SRG), and resulted in a long list of issues needing to be researched.

A joint CAA/UK Government/UK oil industry research fund was created to progress this work and the Helicopter Safety Research Management Committee (HSRMC) was set up to manage and direct it. The committee is still thriving and has evolved over time, expanding its membership to include the UK MoD, the UK helicopter operators (BHA), the new European Aviation Safety Agency (EASA), the Norwegian CAA, the Norwegian oil industry (OLF), and the European Helicopter Association (EHA).

To date, the committee has overseen more than £8M of research spend, spread over a wide range of helicopter safety issues which include:

• Helicopter Health and Usage Monitoring Systems (HUMS)

• Helicopter emergency flotation - ditching stability and water impact

• Helideck environmental issues - turbulence, wind shear, turbine exhaust plumes

• Operations to moving helidecks

• Helideck lighting

• Helicopter Flight Data Monitoring (FDM)

• Use of satellite navigation systems (Global Positioning System, or GPS) for offshore helicopter operations for approach guidance

This research has already led directly to significant progress being made in addressing a number of key safety issues. In particular, HUMS has been fitted to all North Sea offshore helicopters, significantly improving airworthiness, and helicopter FDM is being used to address operational risks at all major North Sea offshore helicopter operators. In addition, work on a number of the other significant safety initiatives is nearing completion and it is hoped that the results and lessons learned can be implemented in the near future.

Helideck lighting is just one such example, and recent accidents such as that near the ETAP platform in February 2009, and the Morecambe Bay tragedy in December 2006 that killed seven people when a helicopter crashed into the sea, have provided the catalyst for the implementation of the results of this research.

It’s not difficult to envisage what a hazardous task landing on an oil rig at night might be. The task can be quite challenging by day, particularly in?bad weather, but everything is harder at night when the pilot often has little more than the helideck lighting to guide him.

The scope for improvement of helideck lighting was common knowledge within the industry, but the results of an offshore helicopter pilot questionnaire-based survey in the mid 1990s added impetus and helped to focus efforts to improve safety. The questionnaire survey was actually performed in connection with a study of the pilot workload associated with the completion of flight deck paperwork, e.g. load and balance, and fuel planning. In fact, all aspects of offshore helicopter operations were covered, partly for camouflage (and, thus, to maximise objectivity) and partly in order that any problems relating to pilot workload could be better set in context.

Six of the 53 questions in the questionnaire related to helideck lighting. For each question, respondents were asked to score statements on a scale of one to ten. Top level analysis of the scores submitted by the pilots indicated that, of the aspects of offshore operations covered by the questionnaire, helideck lighting at night was ranked sixth in terms of contribution to pilot workload, and fourth highest in terms of contribution to safety hazards.

Respondents were also invited to submit written comments for a number of the questions, and a review of these comments identified the following three main areas of concern:

• The location of the helideck on the platform is difficult to establish due to the lack of conspicuity of the perimeter lights - the yellow perimeter lights and white floodlights blend in with the yellow and white light from the general offshore installation lighting

• The performance of most helideck floodlighting systems in illuminating the central landing area is inadequate, leading to a lack of visual cues and the so called ‘black hole’ effect

• Helideck floodlighting systems are frequently a source of glare and loss of pilots’ night vision on the deck, and further reduce the conspicuity of the helideck perimeter lights during the approach

Starting in 1995, a number of experimental lighting schemes were evaluated during a series of onshore and offshore flight trials, culminating in three dedicated trials at the NAM K14B satellite in the southern North Sea. During these trials, a number of changes to the current standard helideck lighting were evaluated. These included:

• Changing the colour of the standard perimeter lights from yellow to green

• Using green electro luminescent panel (ELP) lighting in lieu of the standard perimeter lighting • Adding hoods to the floodlights • Turning the floodlights off

• Illuminating the ‘H’ in the centre of the landing area with green ELP

• Illuminating the inner and outer edges of the landing circle with yellow light-emitting diode (LED) strips These changes were applied in a number of combinations, and the relative benefits were assessed by means of questionnaires that were completed at the end of each approach by the trials pilots, while the next lighting configuration was being set up.

The overall conclusions of this work were that:

• Changing the colour of the perimeter lights from yellow to green greatly increased the conspicuity of the helideck and extended the acquisition range

• Illuminating the ‘H’ in the centre of the helideck with green ELPs significantly enhanced the visual cueing environment during the final approach

Illuminating the inner and outer edges of the landing circle with yellow light-emitting diode (LED) strips significantly enhanced the visual cueing environment from the final approach through to touchdown

• The floodlights, with or without hoods, degraded the conspicuity of the helideck during acquisition and were a source of dazzle to the pilots while the helicopter was on the deck

The recommended lighting configuration for providing a significantly enhanced visual cueing environment derived from these trials was: green incandescent perimeter lights; yellow LED strips illuminating the inner and outer edges of the landing circle; green ELP illuminated ‘H’ and no floodlights.

The preferred configuration from the K14B trials was installed at Longside airfield near Aberdeen, UK, for further experimentation. The main aims of these trials were to evaluate a single lit landing circle (costs are an issue and a single circle would cost half that of the double circle used on the K14B), an outline ‘H’ (again for reasons of cost, but also an outline ‘H’ was expected to provide better cueing than the solid ‘H’ on the K14B), and the effect of a helideck net on the various lighting configurations (there was concern that a net, which would completely cover the circle and ‘H’ lighting, might significantly degrade its effectiveness).

Two trials were completed during 2002, one without a helideck net installed and one with. The overall conclusions of these trials were:

• Without a net, a single ring of yellow LED strips around the landing circle was found to be adequate, and it was judged that this should be located mid-way between the inner and outer edges of the yellow painted marking • Without a net, an outline ELP ‘H’ was found to be better than the solid version

• With a net fitted, there was a greater preference for two rings of yellow LED strips than was the case without the net

• With a net fitted, the solid ‘H’ was much better than the outline version

For logistical reasons, a new test bed was then installed at Norwich Airport to continue the trials work started at Longside airfield. The overall objective of this series of trials was to further improve and refine the revised helideck lighting system, obtain the information required to characterise the landing circle and ‘H’ lighting, to evaluate the suitability of a number of current products and try out some new ideas.

A total of six trials were completed and the results enabled guidance material to be produced for an interim lighting scheme (changing the colour of the perimeter lights to green and replacing the current floodlighting with the new improved configuration), and formally issued to the UK Industry pending availability of the hardware required for implementing the lit landing circle and ‘H’.

However, the main output from these trials was a specification for the illuminated landing circle and ‘H’ marking (instead of floodlighting) for the recommended lighting configuration. The specification was used to tender for the manufacture of a prototype system for installation on an offshore platform for extended in-service trials. The contract was awarded to AGI in the UK, who subsequently partnered with Orga in The Netherlands on this project.

The majority of these trials were hosted on Centrica’s CPC-1 platform in Morecambe Bay, and their purpose was to expose the lighting to a larger number of pilots, and to evaluate the lighting in a broader range of meteorological conditions and thereby validate the specification.

An aerial photograph of the CPC-1 with the lighting installed taken during a demonstration flight performed in November 2009 is shown above.

The trials of the prototype system were completed in Spring 2010. Overall the system performed very well and was enthusiastically received by the pilots. A total of 15 trials questionnaires covering 30 approaches were received. The system was evaluated over a reasonably representative range of meteorological conditions and most pilots strongly agreed that the system represented a significant improvement over current floodlighting-based systems.

Some improvements to the specification were identified and a pre-production version of the system is presently being manufactured and certificated, also for installation on the CPC-1. This will be evaluated during the coming winter night flying season and, all being well, the specification for the new circle and ‘H’ lighting will be able to be finalised allowing the lighting companies to proceed with the manufacture of their production systems.

The first manufacturer of the new system, Orga in The Netherlands, anticipates being ready to accept orders from the beginning of 2011, with the equipment being available ex-stock from around April 2011. A second manufacturer, IMT, also based in The Netherlands, is presently working on a competing design.

The new green perimeter lighting has already been incorporated in the international minimum standards (ICAO in Annex 14, Vol. II) and a slightly modified (improved) version of the specification has been incorporated in CAA’s best practice guidance material (CAP 437). This element of the lighting scheme became mandatory from January 1, 2009 and all helidecks in the North Sea have been modified.

The circle and ‘H’ lighting has been included in the international standards as an acceptable alternative to the existing floodlighting, i.e. it is allowed but is not mandatory. CAA has already published the initial draft specification for the lighting in Appendix E of CAP 437 by way of advance information and, once the trials on the CPC-1 have been completed, will write to the industry providing the final version of the specification and notifying its intention to replace floodlighting with the new circle and ‘H’ lighting in CAP 437.

Although not mandatory, the guidance contained in CAP 437 is widely regarded as a statement of ‘best practice’ and is effectively mandated by other parties such as certifying authorities and/or insurance companies. In addition, the introduction of the new helideck lighting is fully supported by Oil & Gas UK, and it is expected that installation across the majority of North Sea oil rigs will follow over the next few years.

Impacting on what’s considered best practice around the world is clearly an objective any safety house would aspire to. In this instance, while lead by CAA, it’s through the efforts and co-operation of a number of parties that a heightened standard of safety for rig workers and helicopter pilots looks set to be achieved.

The author therefore wishes to acknowledge the vital contributions made by the engineers and scientists at CAA’s research contractor for this project, QinetiQ (Bedford), by NAM and Centrica in hosting the trials on their rigs, by the CHC Scotia Helicopters pilots based at Blackpool in evaluating the system, and by AGI and Orga in making valuable contributions to the lighting specification.

Author

David Howson graduated from City University, London in 1982 with a BSC (Hons) in Electrical and Electronic Engineering. The following six years were spent with his sponsor, British Caledonian Airways, providing technical support mainly for the company’s Airbus A310 and A320 fleets. He joined the Chief Scientist’s Division of the UK Civil Aviation Authority in 1989, becoming a member of a small team managing and directing the Authority’s aircraft safety related research. Devolution of the Chief Scientist’s Division function in 1991 led to a move to the Authority’s Safety Regulation Group where he took over responsibility for the helicopter and helideck safety research programme. In addition to managing safety research projects. David is involved in a number of national and international committees and working groups including the European Helicopter Safety Team (EHEST) led by EASA, the Oil & Gas UK Aviation Safety Technical Group (ASTG), the UK CAA-run Helicopter Safety Research Management Committee (HSRMC), and the Royal Aeronautical Society Rotorcraft Committee. www.osedirectory.com/health-and-safety.php

Published: 10th Nov 2010 in Health and Safety Middle East

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David Howson