One person was killed on Tuesday when a Southwest Airlines jet blew an engine, and the shrapnel shattered a window.
The engine in question is one of the most popular in the world. The CFM56-7B is the exclusive engine for the Boeing 737 Next-Gen aircraft.
According to CFM International, a plane powered by their engines takes off somewhere in the world every two seconds.
In the case of the Southwest tragedy, the 18-year old plane, four years older than average, suffered metal fatigue where the blade separated.
"It's very unusual," said an official with the National Transportation Safety Board.
But not unheard of -- in 1989, a fan blade failed in a CFM engine used by a Boeing 737 in England. The plane eventually crash landed killing 47 of the 126 people on board.
Many of the United States' biggest airlines use Boeing 737s including American Airlines. We reached out to see how many planes in their fleet operate with the same CFM engine but did not hear back.
However, two independent websites, Planespotters and Aerotransport said American has more than 300 of these planes currently in service accounting for almost a third of their entire fleet.
Southwest is ordering inspections of its entire fleet while the Federal Aviation Administration is calling for every airline that flies the 737 to inspect its engines.