Four miles above the English countryside, British Airways Flight 5390 had a serious problem. With a bang, the left windscreen panel had detached itself from the plane and the air was rushing out of the pressurised cockpit, sucking everything out of the plane that wasn’t nailed down. The captain, Tim Lancaster, was hanging out of the cockpit window, his head and torso being battered by the extreme cold and wind, while flight attendants clung onto his legs. Assuming that Lancaster was dead, the crew discussed letting the body go, but decided not to, reasoning that the body might fly into an engine and cause serious damage.
Fortunately for Lancaster, the crew didn’t let go and the plane landed less than twenty minutes later, with the captain suffering with frostbite, bruising and minor fractures. At the time, in 1990, a British Air Line Pilots’ Association described the incident as a “a freak occurrence which will not unduly worry cockpit crews”. The chances of such an accident happening again were vanishingly small.
But nearly 30 years later, on Monday May 14, 2018, a Sichuan Airlines flight found itself in similar peril. The co-pilot was partially sucked out a window after a windshield cracked and blew out while the plane was cruising at 32,000 feet. The roaring wind and freezing temperatures made it almost impossible to communicate with air traffic control, but the pilot managed to land safely and the co-pilot only suffered scratches and a sprained wrist.
Despite these two dramatic flights, these types of incidents are incredibly rare, says Graham Braithwaite, professor of safety and accident investigation at Cranfield University in the UK. Windows are usually made up of several layers of plexiglass and are reinforced so they can survive impacts at high speed. “Windscreens are designed to cope with hitting a bird at full pelt,” says Braithwaite. A crack in an outer pane caused by hail or a birdstrike is not unheard of, but to completely shatter an entire window pane is another matter entirely.
Read more: These are the design tricks that make long-haul flights bearable
Plane windows are also deliberately shaped to keep the pane in place during flight. The edges of the outer pane are wedge-shaped and fitted from the inside so the higher air pressure within the cabin keeps the window plugged against the body of the aircraft. The windshield in the British Airways incident didn’t have this plug design, and it was later found that the bolts used to secure the pane were either too narrow or short to withstand the difference in air pressure during flight.
Investigators will now be trying to work out what went wrong with the windscreen on the Sichuan Airlines flight. One of the problems with this kind of incident is that there aren’t many similar examples to draw on to learn what might have happened, Braithwaite says. Nevertheless, the investigators will be looking to see whether there was a problem in manufacturing or maintenance that might have led to the blowout. They’ll also want to make sure that a counterfeit part wasn’t fitted by mistake. “There are people making counterfeit parts and they are very, very good at it,” Braithwaite says.
Depending on what they uncover, the investigators may then make some recommendations about the way that windows are designed or maintained. The idea isn’t to apportion blame, he says, but to work out whether there is enough evidence to support a new recommendation. “Accidents sometimes help us learn about the best ways of making things more survivable,” he says.
But you don’t need the full investigation to draw some simple recommendations from this flight, Braithwaite says. Unlike the British Airways pilot back in 1990, the Sichuan Airline co-pilot was wearing his seatbelt when the window detached from the plane. “For pilots, who wear a five point harness in the cockpit, they might consider taking the top part off when things aren’t that exciting,” he says. The Sichuan Airlines co-pilot, on the other hand, kept his on, and was quickly pulled back into the plane. “I guess now you’ve got a pilot who would never not wear their seatbelt.”
The same advice applies to passengers. In April 2018, Jennifer Riordan was killed when an engine blew on the Southwest Airlines plane she was aboard, sending a piece of the fan blade flying into the window and breaking it. Riordan, who was wearing her seatbelt at the time, was partially sucked out of the plane before being pulled back in by other passengers, but later died from her injuries.
This kind of incident is even more rare, since plane engines are usually designed to contain debris in the event of an explosion. It was sheer bad luck that the engine part struck the passenger window. In any case, Braithwaite says that the simplest and safest thing you can do aboard any flight is to just keep your seatbelt on at all times while you’re seated, as even if there’s not much chance you’ll get sucked out of the plane, it’ll prevent you bouncing off the ceiling if there is any unexpected turbulence. “If you’ve got a seatbelt and you’re sat down, I’d always put it on.”
This article was originally published by WIRED UK
