Here's what happened on the fatal Southwest Airlines flight (LUV)

Southwest Airline crash

Southwest Airlines Flight 1380 made an emergency landing at Philadelphia International Airport on Tuesday after suffering a major engine failure.
One passenger, Jennifer Riordan, died, and seven others were treated for their injuries.
Investigators believe the engine failed when one of its fan blades snapped off midflight.

Southwest Airlines Flight 1380 made an emergency landing at Philadelphia International Airport on Tuesday after suffering a catastrophic engine failure and cabin decompression.

One passenger, Jennifer Riordan, died as a result of the incident. Her death was the first in an accident aboard a US commercial airliner since 2009.

The aircraft was a nearly 18-year-old Boeing 737-7H4 with the tail number N772SW. It was delivered to Southwest in July 2000.

National Transportation Safety Board investigators believe the left engine failed when one of its 24 titanium alloy fan blades snapped off midflight, causing the front cowling of the engine to disintegrate and firing shrapnel into the cabin of the aircraft.

The engine in question is a CFM56-7B turbofan, the product of a 40-year-old joint venture between GE Aviation and France's Safran Aircraft Engines called CFM International.

The CFM56 is arguably one of the safest and most popular jet engines in the world, with more than 30,000 units produced since 1980, and it's used on both civilian and military aircraft. The CFM56-7B, which debuted in 1997, powers more than 6,700 planes worldwide.

In August 2016, Southwest Flight 3472, another Boeing 737 powered by a CFM56 engine, suffered an eerily similar failure, though no one was injured.

Southwest Airlines CEO Gary Kelly told the NTSB on Tuesday that the airline would inspect its entire fleet of more than 710 CFM56-powered Boeing 737s using ultrasonic technology, which scans the engine's fan blades for microscopic cracks that can be caused by metal fatigue.

Here's how Flight 1380 unfolded.