Lighting the Way

6 January 2008 (Last Updated January 6th, 2008 18:30)

The new Airbus A380 has highlighted the need for improved airfield lighting systems. We consider the history of airfield lighting, and take a look at potential future developments.

Lighting the Way

On 25 October 2007 the Airbus A380 superjumbo completed its first commercial flight with Singapore Airlines from Singapore to Sydney. The superjumbo is an impressive and quite massive airplane which can be configured for up to 555 seats.

The A380 complies with the stricter regulations of London Heathrow airport concerning take-off and landing. Yet many critics are concerned that this juggernaut of an airplane absolutely requires longer runways and improved lighting systems for them.

"The airfield ground lighting sector is worth around £20m a year in the UK."

Although the A380 can complete a 180° turn within a width of 56.5m, which is within the 60m width dimension of standard runways there is now a demand for longer runways due to the appearance of the A380 and with them improved and updated lighting systems.

GROUND LIGHTING GROWTH

But it is not only the A380 which is creating demand for longer runways and new or updated lighting systems to ensure their safety. The increase in domestic and short haul flying too has led to increased demand even at local level and in smaller foreign markets.

As Richard Farmer, product development manager for Alstom a leading company which has been involved in aviation lighting for 75 years said, "The airfield ground lighting sector is worth around £20m a year in the UK, globally it is worth around £200m." A large section of the market in a literally globe-spanning industry and it is a market with good prospects for growth Farmer said, adding "We envisage a tripling of growth within 30 years."

SAFETY FIRST

But what are the lighting systems so central to the safety of air travel? Airport ground lighting systems are those networks of lights and circuits which help guide aircraft in take-off, landing and taxi-ing along the runway, easily overlooked by air travellers but they play a vital role in safe air travel. They must meet internationally agreed standards set by ICAO and the FAA (Federal Aviation Authority).

"Airfield ground lights consist of elevated lights at the side of runways and taxiways and inset lights."

Some have been inclined to see it as a traditional sector, less characterised by innovation than others – an old advert for an airfield lighting manufacturer featured a pensioner telling his grandson that he would grow old before the airfield lamps did. Richard Farmer describes airfield lighting systems as a 'quite a conservative, safety-led technology'.

It would be a mistake to portray airfield lighting systems as unchanging and unsophisticated.

Environmental exigencies have helped drive the development and use of newer forms of technology in the sector and since each airfield is unique, so too are airfield ground lighting systems, which must always be designed on a bespoke basis.

The first use of lights in connection to air transport predates the development of even the most primitive lighting systems and consisted of little more than a beam projected into the skies as can be seen in the image on the right. Each of the 2m metallic mirrors of the aerial beacons reflected a brilliant 800,000,000 candlepower beam of light into the French skies around Paris in 1921.

These airport arc lights each brandished a horizontal set of carbons drawing 300A at 90V. When the atmosphere was clear, a pilot flying at night at around 17,000ft could detect their beams from a distance of 150km.

LIGHTING TRADITION

Conservative or not, airport lighting systems have a long history with the first having been installed in the late 1920s with approach lighting coming into use in the 1930s. These were used to indicate the proper direction and angle of descent with the colours and flash intervals of such lights being standardised by the International Civil Aviation Organisation (ICAO).

The 1940s saw the slope-line approach system introduced. This consisted of two rows of lights that formed a funnel indicating an aircraft's position on the glideslope. In addition to which extra lights indicated incorrect altitude and direction. Since the Second World War lighting systems have become ever more sophisticated, with the addition of computer-controlled systems and in low-traffic airports pilot-controlled systems.

"The industry is looking at light-emitting diodes as a substitute for capsule lamps currently used."

Airport lighting systems have developed considerably since the 1940s increasingly as a result of commercial pressures in what was and remains a dynamic expanding economic sector.

As Richard Farmer said "the airfield ground lighting market is aligned to a country's GDP, and mirrors demand for air traffic, domestic and freight. The more flights, the more area needed, the more lights are needed. It's not just the airfield itself also the infrastructure, the surrounding area."

A happy perspective from an industry insider describes the functioning of airport lighting systems as 'visual aids which help aircraft manoeuvre around the airport, runways and
taxiways, and assist them in landing and taking off'.

Airfield ground lighting works on a familiar principle, he explained. "They're like cats eyes, but for airport users and in fact aren't just used by aircraft but also maintenance vehicles and anything airside. They're dedicated lights, providing a standard lighting pattern throughout the world."

AIRFIELD GROUND LIGHTS

Airfield ground lights consist of elevated lights at the side of runways and taxiways and inset lights which are embedded in the airport surfaces enabling aircraft to run over the lights and withstand 'roll on and roll off' – the impact of wheels on landing.

Farmer said: "There is a whole power distribution and control and monitoring system for these lights. It's like building a fire alarm system, a dedicated monitoring system."

"Airport lighting systems have come a long way since the birth of air transport as a large-scale phenomenon."

Heathrow Airport uses tried-and-tested technology for its airfield lighting, a system known as the aeronautical ground lighting system. A spokesperson for the airport said: "The system enables pilots to follow a path of green coloured lights from the runway, onto the taxiways and to the aircraft stand. Air traffic controllers, at the tower use a touch screen panel to set the lights. The type of lighting guidance system is ideally suited to Heathrow's large and complex operation and helps to ensure a safe and efficient operation."

Alive to the demands on power supply created by such complex systems and mindful of environmental concerns, efforts are being made to design new, more efficient lighting. Farmer added "The industry is looking at light-emitting diodes as a substitute for capsule lamps currently used. They have better, longer lives and use less power. Like any large organisation, power consumption and how to reduce it is an important topic; LEDs are one way."

Paul Gurney of Systems Interface Limited, a leading British-based company specialising in air traffic control systems capability, is optimistic about the continued expansion of the market for airport lighting systems. Systems Interface, which installs but does not manufacture lighting systems, is currently working on a contract in Gambia for replacement lighting systems at Banjul International Airport, the first phase of which has been estimated at approximately £800,000 with the
entire project costing an around £2m.

According to Gurney this is a normal cost for an airport lighting system. The FAA estimates that such systems will normally last for 15 years. It notes that the A380 Superjumbo can be used in conjunction with existing systems and facilities but runway services will need to be upgraded at which point it is expected that lighting systems will be similarly upgraded.

Describing a typical lighting system Gurney said "Lighting systems are always bespoke, the basic system is always the same but each airfield is different. The technology we use for lighting airfields is fairly basic – the system lights run on a constant current of 6.6A. You have circuits cabling around the airfield like a ring main system. Each lamp has a transformer attached to it and a constant current ensures that at the same airfield, the lamps are at the same brilliance.

"The original airport arc lights each brandished a horizontal set of carbons drawing 300A at 90V."

On runway-edge lighting and approach lighting circuits you have interleaved circuits, with every other lamp connected to the same circuit so if one circuit fails or there is a cable fault, you still have a pattern of lights around the runway. So there is still a pattern of lights for the aircraft so the runway edge can be seen."

Airport lighting systems have come a long way since the birth of air transport as a large-scale phenomenon.

But despite, or perhaps because, it is based on proven slow developing technologies, it is today an established and crucial part of the expanding air transport industry.