In most cases when people seek window glass repair, the problematic pane is on solid ground, and often the main consequences of a window being cracked or broken are that it allows cool air in and reduces energy efficiency and can affect security.
A more concerning situation, by comparison, is if a window happened to break on an aeroplane whilst it was flying tens of thousands of feet in the air, as nearly happened recently on a flight from Warsaw to New York.
Ultimately, the glass was fine; the UV-shielding layer of the window tore, but the window seal was unaffected, meaning that outside of giving passengers a fright, no harm was done.
Aeroplane windows have three layers and can take a huge amount of force before they finally break, and in practice, it is very unlikely for it to actually occur, although there have been a few cases of it happening in real life.
However, what would actually happen if a window happened to break? The first immediate event is that all the air in the plane would rush out, as the internal and external air pressures are different in order to allow people to breathe easily whilst in the sky.
This rush can create a kind of suction effect, which can suck objects out of it, including potentially people, before causing the temperature and air pressure to fall rapidly.
However, given that the immediate response is to descend, these forces will take effect until the plane descends to a level low enough to compensate for the cabin pressure loss, usually around 8000ft in the air.
There have been three cases where it has happened, with one tragic loss of life:
- On British Airways Flight 5390 on the 10th June 1990, a poorly installed windscreen panel fell out, causing flight captain Timothy Lancaster to be sucked out of the plane, only held in by flight staff. He survived with a fractured arm, frostbite and a few other minor injuries.
- In 2018, Sichuan Airlines Flight 8633 had the same issue, with first officer Xu Ruichen being sucked out of the aircraft, suffering minor injuries. This incident eventually was adapted into a film called The Captain.
- Finally, Southwest Airlines Flight 1380 had one of the passenger windows break due to an exploding engine, causing a passenger to be partially sucked out of the plane, sadly dying from her injuries.