January 14th, 2013
I’M OBLIGED TO SAY SOMETHING, anything, about the incident on January 12th in which a Southwest Airlines 737 landed at the wrong airport.
The plane was destined for Branson, Missouri, and instead ended up at a small general aviation field nearby, touching down on a runway less than four thousand feet long.
Twice in two months this has happened. Back in November, a 747 freighter operated by Atlas Air found itself at the wrong airport in Kansas. Much of what I said then applies this time as well, so allow me to repeat myself, beginning with the disclaimer that these things are often more complicated than they seem on the surface, and we probably shouldn’t speculate too broadly until more is known.
The question I keep getting is “How could such a thing happen” — with a incredulous tweaking of the word “how.” I can’t be sure if this is asked rhetorically, or if people expect a neat and concise answer (aside from the obvious, which is that the crew made a terrible mistake).
Because, unfortunately, there isn’t a neat and concise answer.
In addition to whatever human mistakes are to blame, weather and air traffic control, among other factors, can lend a hand in getting from point A to point B — or, in this case, point C. Take, for example, the case 19 years ago of a Northwest Airlines DC-10 that touched down in Brussels instead of Frankfurt. It turned out that air traffic controllers had been given the wrong information, and began issuing a long and complicated series of vectors and course changes to the crew, sending it toward Brussels instead of Frankfurt. Airspace in Europe is complex and often very congested, and roundabout routings aren’t uncommon. Thus it wasn’t necessarily obvious to the crew that they were being led astray. Due to fuel constraints, by the time they realized what was happening, they opted to continue on to Brussels rather than request a re-clearance to Frankfurt. In other words, at a certain point it was * safer * to land at the wrong airport than the right one.
What happened in Missouri and Kansas may have been a lot different, and it’s very possible that a failure of basic flying skills was the primary culprit. But the moral is that there’s typically more to these situations than the media coverage implies.
The Southwest pilots were flying a so-called visual approach into Branson. Most of the time, jetliners land using what we call an ILS (instrument landing system) in which ATC guides us onto a pair of crosshair signals — one vertical, the other horizontal — that we track to the runway, either manually or by coupling the ILS to the plane’s autoflight system. There are also what we call “non-precision” instrument patterns, which guide aircraft toward the general vicinity of the runway, if not to the very threshold as with an ILS. Visual approaches are used when ceiling and visibility are above certain parameters — in other words, when the weather is good. Here, as the name of the procedure implies, the crew identifies the airport by sight, and continues toward the runway through whichever course and pattern is most practical. Sometimes a visual approach is backed up with an ILS, but not always, and in some cases there’s substantial low-altitude maneuvering. In other words it’s a very hands-on procedure.
That doesn’t make what happened in Missouri acceptable, or the kind of thing we should expect. Airline pilots perform thousands of successful visual approaches every day in this country without incident. But neither are such errors unprecedented, and certain combinations of circumstances make them more likely: a nighttime visual approach with low-altitude maneuvering, for instance, together a crew’s unfamiliarity with the destination airport, and perhaps a similarly laid-out airport nearby. Add to this a failure to use secondary navigational aids or otherwise verify the runway they’re looking at is the runway they think they’re looking at, and suddenly it’s not so unthinkable.
And for better or worse, incidents like these remind us that commercial flying remains a very hands-on experience. Despite everything you hear about autopilot and the alleged sophistication of modern jetliners, it’s the fight crew — the pilots — who are very much flying the airplane. While I wish there were a better illustration of it, sometimes it takes an embarrassing mistake to make this point clear.
Photo composite by the author