Chris Gerrard in the Ambient Light Facility

The ALF, located at our site in Warton, Lancashire is capable of generating light equivalent to the power of 72 lighthouses and was specially designed to replicate the full range of lighting conditions pilots face every time they take to the skies. Built in 1992, it's one of only two such labs in Europe.

Light Fantastic

The ALF boasts an impressive suite of lighting. Whilst just one 3kW Xenon arc bulb is enough power to run a lighthouse, the ALF has 72 of them - creating a mighty combined total of 216kW.

There is more lighting power in the ALF than in the Oval Cricket ground's floodlighting, but this is concentrated into a 9-metre diameter 'Igloo' space that's more similar to the size of a squash court.

Blinded by the light

All of this power is employed to simulate the blinding impact of sunlight bouncing off the top of a layer of cloud - just as the pilot would see it at 12,000 ft. The inside of the space is painted using a special reflective white paint to best replicate this effect.

What's it all about ALF?

In the centre of the ALF sits a fully equipped Typhoon Cockpit test rig with its three main display screens. This is the real focus of all this attention. Our engineers analyse how these displays cope with a variety of lighting scenarios that they set up.

Light poses a significant challenge to our engineers and pilots.  When a Typhoon pilot takes to the skies, their eyes have just fractions of seconds to adjust as they travel through cloud and bright light.  During those rapidly changing conditions, they must be able to view the vital information of the screens in front of them.  The cockpit displays have to be clear and legible at all times - whether it's shade one second or bright sunshine the next, and those extremes pose quite a design challenge.

A series of eight sensors in and around the cockpit help the aircraft to make real time automatic changes to the light emitted by the displays, keeping them at the optimum brightness for the pilots.

Good lux

Light is measured using a lux meter and whilst the average office lighting level is around 600 lux, the Ambient Light Facility generates closer to 20,000.

Chris Gerrard, Lighting Test Engineer said: "It's just what you'd normally see when you look down whilst flying over the top of full cloud cover during the day."

A whole range of other lighting effects can be reproduced in the facility too. As well as the arc lamps there are a further three 4-kilowatt movable 'sun guns'. Much like TV studio lights, these are used by the team to provide a focused illumination on specific cockpit displays and indicators. 

Sunny days

Says Chris: "The sun guns give us a blast of intense light in a limited area that is over 100,000 lux. That's the equivalent of direct overhead sunlight at 20,000ft."

At the other extreme of the spectrum the dome can be transformed into a star and moonlit night at the flick of a switch.

These days a lot of the work on lighting can be done using computer modelling. This approach has become increasingly sophisticated and accurate but ALF still has its uses because the real test of whether a display works under bright light is carried out by humans rather than computers.

The Sunshine Club

Over the years our team has worked with the firms who make displays for bank ATM machines as part of a group called The Sunshine Club. This group brought together a range of manufacturers who were tackling lighting issues.

Most recently the facility has been used to test modifications in the cockpit.  For example, the integration of new night vision goggles for Typhoon and a new display on Tornado.