The Southwest plane window blew out after engine explosion, but airplane windows are stronger than you think

NTSB/AP

• Southwest Airlines Flight 1380 made an emergency landing in Philadelphia after suffering an engine failure and cabin depressurization.
• One of the Boeing 737's windows blew out, nearly sucking a passenger out of the cabin.
• Airplane windows are rather durable and are made up of multiple layers.

On Tuesday, Southwest Airlines Flight 1380 made an emergency landing in Philadelphia after an uncontained engine failure damaged the plane's fuselage and one of the Boeing 737's windows blew out. The resulting decompression managed to nearly suck Jennifer Riordan out of the window before being pulled back in by her fellow passengers.

Unfortunately, Riordan, 43, died from her injuries.

This leads us to ask the question: What is an airplane window made of and what kind of forces can it take?

Investigators from the National Transportation Safety Board believe the failure occurred when a titanium alloy fan blade snapped mid-flight. The damage to the window and fuselage may have been the result of shrapnel caused by the disintegrating engine cowling forced out by a rogue fan blade spinning near the speed of sound.

The NTSB does not yet know what exactly blew out the window, but whatever debris that managed to puncture the window did so with incredible force.

The window on modern airliners is actually made up of multiple layers, usually three, of acrylic with a plastic inner cover. The three layers are gapped and vented. This is to allow for pressure equalization and to prevent the windows from fogging. The material used to make the windows is rather durable and, following federal regulations, won't splinter when damaged.

Since the windows are essentially made from plexiglass, they aren't bulletproof. However, they rarely fail. And even if they do, modern airliners such as the Boeing 737 used to operate Flight 1380 can survive and land after most depressurization events.

Read More about the Southwest Incident:

• Southwest passenger's death was the first in a US passenger airline accident in more than 9 years
• Southwest pilot to air traffic control before emergency landing: 'There's a hole and someone went out'
• Southwest passenger says there was 'blood everywhere' after 'terrifying' emergency landing
• Southwest passenger who died after major engine failure has been identified as a Wells Fargo VP and mother of two
• Investigators found a major clue to what may have caused Southwest jet's engine failure
• The type of engine that blew apart on Southwest plane was a growing concern for regulators
• The pilot who made the Southwest flight emergency landing is a former fighter pilot and one of the first women to fly an F-18
• Southwest passenger's torso was sucked out of plane after engine explosion busted open aircraft window