The extreme engineering of aircraft windows

The extreme engineering of aircraft windows. Few companies have the technology to make aircraft windows which are getting harder to make.

What happened

The tank belonged to GKN Aerospace, a company that supplies parts to the aviation industry, including aircraft windows. But production of aircraft windows at the site, which had been halted, is still not fully restored. Image source, Getty ImagesImage caption, Very few companies make aircraft windowsThis has sent a minor shockwave through the aircraft manufacturing industry because GKN is one of surprisingly few companies, anywhere in the world, that make aircraft windows – highly engineered, safety-critical parts for planes.

Image source, Saint-GobainImage caption, Windows start with a sheet of acrylicTo find out what goes into the making of an aircraft window, I spoke to Jean-Eric Vermont, general manager of French company Saint-Gobain Aerospace. Vermont declines, though, to say how much market share his company has in aircraft windows – or transparencies, as they are known in the trade. Aircraft manufacturers are increasingly ordering larger cabin windows, says Vermont, in order to offer passengers a wider view of the world outside.

Saint-Gobain tests its windows by exposing them to pressures many times what would be normal on an aircraft flying at altitude.

The wider picture

Image source, Saint-GobainImage caption, As aircraft windows get bigger, they get harder to manufactureCockpit windows, Vermont says, are "totally different". Some of the latest aircraft feature cockpit windows that are also curved, to make the plane more streamlined, which improves fuel efficiency. All aircraft windows must be resistant to impacts but cockpit windows, at the front of the plane, are especially vulnerable to bird strikes, says Vermont: "The issue is not the speed of the bird, the issue is the speed of the aircraft.

"They're one of only a handful of suppliers – less than a handful, really – of critical windows," says Marisa Garcia, an aviation industry analyst. "It comes at a time when airlines "can't get new aircraft fast enough," says Mike Stengel of AeroDynamic Advisory, a consultancy. "Even though there are just a few aircraft window-manufacturing firms in existence, it's hard for new competitors to emerge because of how regulated the industry is, adds Stengel. "We focus mostly on commercial aircraft, regional aircraft and helicopters," he says.

The oval-shaped windows in the cabin, next to passengers' seats, are typically made of plastic-based materials, says Vermont.

What has been reported

It's a selling point but it requires additional testing to ascertain whether the bigger windows hold up as well as the smaller ones. These acrylic-based cabin windows are usually made out of two layers or plies, and Saint-Gobain also performs tests to confirm whether the window will survive even if one of those plies gets damaged. But curved cockpit windows are challenging to make – the slightest distortion or defect is clearly visible to the pilot.

"Saint-Gobain uses numerical simulations and "physical tests representative of a sizeable bird impact" to test its windows against this threat. "There can be [such] cases," says Vermont, though he adds that Saint-Gobain's windows have not been involved in any recently. Image source, Los Angeles Times via Getty ImagesImage caption, Fire crews hosed down an overheating tank in Los Angeles in MayByChris BaraniukTechnology reporterPublished5 hours agoAn industrial nightmare was brewing south of Los Angeles. In late May, a chemical storage tank with more than 7,000 gallons of toxic material began heating up – fast.

As the temperature inside the shiny metal storage vessel rose, workers realised they had a problem.

What happens next

The tank was at risk of exploding, potentially showering nearby neighbourhoods with methyl methacrylate (MMA), a skin and lung-irritating, external compound used in plastics production. The tank's temperature reached 100F (38C) – though possibly went higher – 100F was simply the maximum reading, external on the temperature gauge inside. More than 50,000 residents of Garden Grove city were evacuated and fire crews began hosing down the tank in a bid to cool it. At one point, the vessel "actually bulged" according to the local fire chief.

Months later, in August, GKN and local authorities announced a $100m (£74m) programme, external to compensate residents evacuated during the incident. Production at GKN's Garden Grove facility currently remains hobbled, at roughly 50% of normal, according to public statements, external by its UK parent company Melrose Industries. The aim is to have full production restored by 28 September.