What’s the difference between an emergency landing and a diversion?

Emergency personnel monitoring the damaged engine of flight 1380.
Emergency personnel monitoring the damaged engine of flight 1380.
Image: Reuters/Mark Makela
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The last thing a passenger wants is for their plane to land unexpectedly. It can happen for a range of reasons, from a sick passenger or bad weather, to an engine failure. But whether your flight landing in the middle of nowhere was considered an “emergency” or a “diversion” is a semantic distinction that airlines are cautious to get right.

Just ask the New York Times, who last May had to print a correction (paywall) when they described a Southwest flight as undergoing an emergency landing after a passenger window was damaged mid-flight. In actual fact it was technically a diversion, as no danger was posed, Southwest noted, despite the damage.

The distinction between an emergency landing and a diversion might seem simple. Generally, a true emergency landing is rare, and occurs when the safety of the cabin is in danger, meaning a landing needs to be made ASAP. It’s a call that’s made by the pilot, and can also signal that priority handling by ground crew and emergency services is required.

Such was the case a couple weeks before the aforementioned Southwest incident, when Southwest flight 1380 resulted in the first accident-related death on a US passenger airline since 2009. In this case, the fuselage and window were damaged by debris from an uncontained engine failure, a rare occurrence when engine components exit the casing, often violently and in a way that causes further damage to the aircraft.

On the other hand, a diversion or an unscheduled landing is used to describe a situation where a precaution is being taken, or it’s in the best interest of passengers on board (like when dueling lovers were so disruptive on a Qatar Airways flight, the pilot decided to ground the aircraft.) Diversions will generally go to an airport where it’s convenient for the airline to rebook passengers from once they land—not necessarily the one closest by. They’re basically “flights to nowhere,” an occurrence once live-tweeted by Chrissy Teigen when her long-haul flight from LA to Tokyo turned around midway and headed back to where it came from.

But perhaps confusingly for passengers, serious-sounding incidents, such as contained engine failure or technical issues—something that a layperson would surely describe as an emergency—are often classed as diversions. That’s largely due to advancements in aircraft design, which include multiple redundancies so that airplanes are able to fly safely even when one engine is non-operational.

As Robert Stangarone, the managing director of an aviation-focused communications firm puts it, in the event of in-flight engine shut-down, “the prompt landing is a precaution against the risk that another engine will fail later in the flight. It’s a relatively controlled situation unless it was a catastrophic event (an uncontained failure, for instance) that damages critical parts of the aircraft (fuselage, control lines, hydraulic systems, etc).”

So while it may sound or feel like an emergency, the commercial aviation industry has good reason to avoid using that word unless they have to. Air travel is, of course, statistically very safe—and airlines would like you to continue to feel that way. But the FAA confirmed to Quartz that it is ultimately up to the airline to decide when to class an incident as an emergency landing or not. A rep also reiterated that “it is possible to divert or make a precautionary landing without declaring an emergency.”

Stangarone says that while airlines follow a general rule of thumb, it’s not black and white, and airlines will understandably be interested in wanting to keep a strong safety record. “Since it can be a gray area, airline PR officials, when responding to press queries, will try to defuse the issue as much as possible,” Stangarone said. “That leads to judgment calls on how to respond in the fog of the aftermath of the event.”

Since emergency landings are often misreported, it can seem like they’re happening a lot. In reality, diversions are far more common and, since they’re done out of an abundance of caution, should give travelers less cause to worry.