LED lighting at Glasgow and Gatwick

Writing for this magazine (‘Light-Emitting Diode airfield lighting systems’, International Airport Review, Issue 5, 2012), John D. Bullough, Senior Scientist at the Lighting Research Center at Rensselaer Polytechnic Institute commented that Light Emitting Diode (LED) airfield lighting was increasingly being used due to the “potential for this technology to produce substantial savings in terms of maintenance and cost.”

In the United Kingdom, both north and south of the Scottish border, LED airfield lighting is becoming more and more commonplace amongst the nation’s airports, which are keen to take advantage of these benefits. Ian Sharp, Lead Engineer at Gatwick Airport, in South East England mirrors Bullough’s view that the technology is highly efficient and superior to the airports’ previous lighting programme of tungsten/halogen fittings: “One of the advant – ages of LED lighting is it lasts longer, with an excess of 50,000 hours or over seven years, whereby tungsten-halogen lamps typically last 2,000 to 5,000,” Sharp says. 

LED technology is now standard at Glasgow Airport, after being tried and tested on the taxiway pavements. Gatwick meanwhile, formed part of the Airport Operators Association’s (AOA) sub-group, which produced all the necessary trial documentation to integrate the LED lighting within the airfield.

Making the switch

Switching from any type of technology to a preferred sort is never straightforward. The process is made even more complicated within the airport industry, where replacing established deep-rooted systems is normally preceded by testing and research and then eventually authority sign-off. At Glasgow Airport, the decision to convert to LED lighting required a substantial amount of runway renovation. The Airport’s owner, BAA, decided that it would be best to incorporate any major airfield lighting works into any runway rehabilitation construction. This process was overseen by Glasgow Airport’s Lead Engineer, Peter Chalmers, who explains the reasons behind the decision: “BAA’s strategy was agreed that (LED) replacement be undertaken on an airfield block-by-block basis during major project works to taxiways. The change of fittings requires new seating pots, new transformers and in many cases new primary and secondary cabling – hence these works are generally kept to major rehabilitation projects.”

Glasgow’s first runway/airfield lighting took place with the Alpha Taxiway in 2009 and then the Golf Phase 1&2, Kilo, Lima, Quebec and Mike runways in 2012. Since then, the UK CAA have approved the use of LED fittings for runway circuits and looking forward, Glasgow intends to replace its runway Airfield Ground Lighting (AGL) fittings to the LED type within the next runway rehabilitation. Ultimately, the work is strategically planned to reduce interference at the airport, as Chalmers is keen to point out: “These works require the temporary de-commissioning of the current AGL routes, causing loss of taxiway lighting systems – all of which is well planned and agreed with by the CAA well in advance, allowing for minimum operational disruption throughout the duration of the works.”

Standardisation and safety

Within the airport and aviation industry the standardisation and governance of AGL carries a huge amount of significance. The sector is extremely dependent on working groups, associations and documentation, which means it operates within water-tight yet essential guidelines.

This standardisation also has a number of benefits for the industry, creating competition amongst suppliers, which according to Sharp will “enhance innovation for further reduction in energy consumption, and the ease in which parts can be replaced, and the reduction of dirt build-up.” As always, safety remains the most important aspect and in particular the viewpoint of the pilot, something Sharp emphasises: “It is not in the interest of airfield safety to have different ways of providing pilot guidance at an airport. Pilots fly between different airports every day, so it is important that we aim for some visual consistency and international standards to help achieve this.”

Of course, the pilot’s perspective is an integral part of AGL testing. Gatwick, for example, continually gathers feedback from pilots and their views of the LED runway fittings, and so far the response has been extremely positive. ‘Blind’ spots appear for pilots when mixed airfield blocks incorporate both tungsten/halogen and LED fittings, these ‘mixed’ blocks are no longer approved by the CAA, although on occasion the Authority has allowed block-by-block type changes, provided that they are on different circuits, so that the LED circuits can be ‘turned down’ to reduce the contrast in brightness between types.

Vision

Busy runways, such as those at Glasgow and Gatwick Airports, can become extremely dirty having a detrimental effect on a light’s performance. Rubber from aircraft tyres as well as a combination of rain and chemicals from winter de-icing solutions can gradually obscure the light that is given off. To overcome this Gatwick has a number of solutions, as Sharp explains: “Gatwick has a special light measurement trailer which can accurately record the light intensity. This is used regularly and can identify where cleaning is most needed. We will also conduct frequent visual inspections every day and gather feedback from pilots using the runway.”

Finding the correct fitting and product again takes a large amount of trialling and it must comply with national and international regulations to meet the requirements of that aerodrome’s licence. At Gatwick, Ian Sharp and his team keep their fingers on the pulse of the industry: “Gatwick plays an active part in keeping up-to-date with technology,” Sharp says. “We maintain a good network of contacts and attend seminars to continually assess what is right for the airport.”

Advantages and benefits

As mentioned at the beginning of this article, one of the many advantages of LED fittings is its similar cost to that of the tungsten/halogen models whilst using approximately 40 per cent less power. Glasgow Airport specifically uses the ADB LTS/LTC type manufactured by ADB Airfield Solutions. Peter Chalmers is enthusiastic about the product and its benefits: “The model requires an ADB eight inch HPI seating pot or adapter plate to retrofit to existing seating pots. LED fittings are quoted with a life expectancy of 50,000 hours as opposed to 1,500 hours for tungsten/halogen equivalent fittings. Cleaning is obviously required for both types of fitting, although the LED fitting operates at lower temperature, meaning less debris sticks to the surface.”

The airport’s relationship with ADB has been a prosperous one, even before LEDs were approved for runways, ADB supplied the approved tungsten fittings after a working group’s appraisal at Edinburgh Airport put the manufacturers as the preferred choice. Chalmers continues: “Before the Alpha taxiway at Glasgow was to be resurfaced the appraisal was reviewed and ADB still came out on top. This time it was possible to use LEDs, and ADB’s taxiway fittings were utilised.”

At a time when airports are making every penny count, whilst keeping an eye on their carbon footprints, LEDs seem the most appropriate way to take airfield lighting forward. Their financial and environmental benefits are important but following thorough testing through various working groups, their purpose is to guide an airplane safely through descent and, as ever, safety is, and has to be, the number one priority.

About the authors

Peter Chalmers joined Glasgow Airport in 1998, spending three years as Planning and Energy Manager and a further three as Environment Manager before being appointed Airport Lead Engineer. Between 2004 and 2009 he was Lead Engineer for BAA Scotland, with responsibilities at Glasgow, Edinburgh and Aberdeen airports, before the umbrella body was dissolved in 2009. Between 2004 and 2007 he set up asset management systems across the three airports, ultimately helping Glasgow Airport achieve the PAS 55 Asset Management Standard. Peter, a Chartered Electrical Engineer, studied Electrical Engineering at Queen’s University, Belfast, and graduated in 1983. He held a number of engineering roles in a range of industries before joining Glasgow Airport.

Ian Sharp previously worked as a graduate trainee for BAA (based at Gatwick) from 1990. Before that (1981 – 1985) he worked at GlaxoSmithKline (GSK) as an electrical apprentice.