- Southwest Airlines flight 1380 suffered an engine failure on Tuesday forcing the pilot to make an emergency landing.
- Airline pilot and author Patrick Smith explains that there are two ways a plane's engine can fail. The Southwest Airline's flight suffered what is known as uncontained engine failure.
- However, Smith said that in general, aircraft engines are incredibly reliable, and unconfined failures are the rarest type of malfunction.
Editor's note: Patrick Smith is a commercial airline pilot who currently flies Boeing 757 and 767 aircraft. Smith also runs the blog AskThePilot.com and is the author of the book "Cockpit Confidential."
Uncontained engine failure is the term you’ve been hearing, and it aptly describes what befell Southwest Airlines flight 1380 on Tuesday on a flight from New York’s La Guardia Airport to Dallas.
Basically, a jet engine can fail one of two ways. The first and more innocuous way is that it simply shuts down and ceases producing thrust. This is more or less akin to switching off the ignition in your car.
Of course, all commercial jetliners have at least two engines, and can fly just fine should this happen. In fact, per certification requirements, should an engine quit even at takeoff speed while still on the runway, a plane still has enough power to become airborne and climb safely away — a performance buffer that all pilots are intimately familiar with; the so-called "V-1 cut" being a maneuver we practice regularly in the simulator.
More dangerous is the uncontained engine failure. As the name implies, this type of failure involves the high-velocity ejection of an engine’s internal components. The moving parts of a jet engine consist of a series of discs — fans, shafts, compressors, and turbines — spinning at tremendous speeds. Should any of these discs fracture or otherwise come apart, whether from an unseen crack or some immediate trauma, the extreme centrifugal forces can send bits of metal straight through the cowling and into the airframe, potentially penetrating the cabin or even the fuel tanks.
Luckily this almost never happens. Aircraft engines are incredibly reliable, and unconfined failures are the rarest type of malfunction. But when they do happen, the results can be deadly. As was the case aboard the Southwest 737. One passenger was killed and several were injured by shrapnel that pierced the cabin. The crew made an emergency landing in Philadelphia.
Two years ago, an uncontained engine failure on an American Airlines 767 touched off a fire that destroyed the aircraft on the runway. A similar incident involving a British Airways 777 occurred in Las Vegas in 2015. And in 2010, shrapnel from a failed engine caused a cascade of dangerous system failures aboard Qantas flight QF 32, an Airbus A380 flying between Singapore and Sydney.
Nobody was killed in any of those accidents, but two passengers died in 1996 when a turbine disc of a Delta Air Lines MD-88 came apart on a runway in Pensacola, Florida. And, most infamous of all, 111 people died in 1989 when United Airlines flight 232 crashed in Sioux City, Iowa, after a fractured engine disc took out all of the widebody DC-10’s hydraulic systems. (That last one was due more to a design flaw in the hydraulics system than a fault of the engine.)
Maybe that all sounds scary — and the media, predictably, is going cuckoo over Southwest. But we’re talking about a small handful of fatalities over more than a quarter of a century.
The death of the passenger on Southwest 1380 is the first fatality involving a U.S. major air carrier since 2005, when a southwest 737 slid from a snowy runway in Chicago and collided with a car, killing a young boy.
The fuselage breach also caused the cabin to rapidly decompress. Without going off on too much a tangent here, this would have been a dramatic but perfectly manageable secondary problem.
Some decompressions are more hazardous than others. Bombs, for example, can cause an entire fuselage to tear apart in seconds. Large-scale structural failure, like the fuselage burst of an Aloha Airlines 737 in 1988, can be similarly disastrous.
But those are rare occurrences. The vast majority of decompressions are harmless. Even sudden decompressions — such as when engine parts tear through a window, as apparently happened on Tuesday — are pretty easy to deal with. Essentially, the pilots don their oxygen masks and initiate a rapid descent to a safer altitude (normally ten-thousand feet). Passengers, meanwhile, have ample supplemental oxygen if need be. An emergency descent might feel very abrupt, but it will be well within the capabilities of the airplane.
The crew of flight 1380 certainly had its hands full: a disintegrative engine failure, together with a rapid decompression and serious injuries to passengers, is no pilot’s idea of a good time. But despite what you’ve probably seen online or on TV, the plane was never in any danger of crashing. By all accounts, the crew — both the pilots and flight attendants — did an outstanding job. That is to say, they did exactly what they were trained to do, what they were supposed to do, and what they were expected to do.
And on that note, please be wary of passenger accounts. Some of the quotes I’ve seen are nonsense. Claims that the jet was in “free fall,” was “diving toward the ground,” or was in any way out of control are simply untrue. I don’t blame anybody on the plane for being scared, but passenger accounts in situations like this — more specifically, the way they are packaged and quoted by the media — are notoriously inaccurate and prone to exaggeration, almost to the point of being totally unreliable.
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