Window of opportunity: Replacing Stansted's glass

After a year of meticulous planning, the windows in the air traffic control room at Stansted Airport have been replaced.

What is a control tower?

UK airspace contains a network of corridors or airways. They mainly link busy areas of airspace known as terminal control areas, which are normally above major airports. At a lower level, control zones are established around each airport and this is controlled from an airport tower.

The airport tower has been synonymous with air traffic control for as long as the modern concept has existed and is often an iconic airport landmark.

Inside the visual control room, housed in the highest point of the tower, controllers look after all airport traffic including ground movements, landings and take-offs.

Stansted tower was opened in 1996

Standing 65-metres tall, Stansted’s control tower is ‘the office’ for a team of controllers.

The current tower was opened in 1996 and while much of the technology inside has changed, the tower itself has remained the same since then, including the windows.

However, after finding one cracked pane, several showing age and the laminations starting to separate, the team at Stansted decided it was time to take action.

Stansted’s operation 2017:

  • Flights: 190,000 (+5% on 2016)
  • Passengers: 25.9m (+7% on 2016)
  • Busiest ranking: 4th—UK’s busiest airport (flights)
The windows are the most important tool in the controller’s role, they need to look out to view aircraft on the ground and in the sky.

Pulling off a project as complex as this took more than a year of meticulous planning.

Working together with the airport and our suppliers, NATS had to complete the project without affecting operations at the airport.

The 27mm thick glass was chemically toughened and tinted with a heating element to prevent condensation or fogging on the inside. It was transported to Stansted from Germany & Switzerland, which took a number of months.

The project took more than 16 days to complete, using one of the tallest mobile cranes in Europe.

Key individuals from the airport fire service and facilities management business partners worked tirelessly to support ATC and ensure a seamless service as they moved backwards and forwards between VCR and contingency VCR with zero impact to the busy traffic schedules."

Martin Ruddy, Stansted control tower GM.

The windows are fitted with an anti-glare film.

To transport the glass up to the control room, each 335kg glass pane was connected to a suction lifter and failsafe strap before being hoisted up via crane.

But before installing the new glass, the old panes had to be removed. To do this the existing seals were cut out by a group of technicians using a high level scaffold. Once loose, the old glass was attached to the suction lifter and lowered into a skip on the ground.

Whilst the glass was out of the building, the frame was cleaned ready for the new glass, which was then lifted and guided into position by technicians at the top of the glazing. Once in position, the window clamps were refitted to secure the glass in place.

The tower was left secure and water tight after each shift to ensure the equipment was protected.

This was a monumental project for the Stansted team. From planning to practical implementation, the importance of team work and having a structured approach to ‘our bit’ of the process was evident.

Martin Ruddy, Stansted control tower GM.

Care and attention was taken to complete the project on schedule.

Stansted runs a 24/7 operation, so it was especially important to ensure the glass replacement had no impact on the travelling public. Although there are very few aircraft movements throughout the night, a controller must be on-shift at all times in case of an emergency.

While the work took place, the controller temporarily relocated at 22:30 each night to a small observation tower in the airport’s fire station building. This contingency control room is equipped with all the correct technology and acts as an emergency stand-by in the event of fire or other evacuation from the main control tower.

NATS spent more than 18 months preparing for the project, working alongside the airport team to co-ordinate the project to ensure it was a success.

In September the finished tower with its new set of 16 weather-proof windows was unveiled, giving the controllers an even better view of the airfield.

Whilst I would like to thank all the staff involved for their tremendous efforts, special mention must go to Ron Sloan (NATS Facilities Management) and Lynne Webb (Stansted Watch Manager) who were essential in the strategy and planning development of this milestone in the history of the tower."

Martin Ruddy, Stansted control tower GM.

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NATS Digital Communications