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How can a plane land at the wrong airport?

        Science | Modern

Project Runway

The Boeing Dreamlifter example illustrates one of the most common causes of airport screwups: namely, two or more airfields lying in close proximity and sharing similar runway alignments. Dozens of airstrips lie scattered across the metropolitan area of Wichita -- the self-proclaimed "Air Capital of the World," thanks to its strong aircraft industry presence. The region surrounding McConnell Air Force Base alone boasts at least five [source: McMillin]. Consequently, when the Atlas Air pilot got his position wrong, he got it even more wrong than he realized: He thought the plane had landed at Beech Field, not Col. Jabara [sources: Jamieson and Chuck; LeBeau].

"Giant 4241 Heavy, do you know which airport you're at?"

"Well we think we have a pretty good pulse. Let me ask you this ... how many airports...directly to the south of ... your 1-9 are there?"

The likelihood of mistaken landings varies according to the landing system used by the pilot. Under an instrument landing system (ILS), the pilot or aircraft autoflight system tracks a set of crosshair signals all the way to the runway and therefore has little chance of wandering off the beam, provided that flight plan info is inputted correctly. On the other hand, pilots using a visual approach -- in which the crew recognizes the airport by sight and plots the most practical course and pattern to the runway -- have more rope with which to hang themselves. Both types of approach are common.

Between these two lie a number of "non-precision" instrument patterns, including the area navigation (RNAV) system that the Dreamlifter used. RNAV relies on inertial guidance and/or external course-plotting systems -- such as navigation satellites (GPS) and older VOR (very high frequency omnidirectional range) and DME (distance measuring equipment) signals -- to reach the field's vicinity. After that, it's up to the flight crew to sight the strip and land via a visual approach. This, too, leaves room for mistakes, which is why regulations require crews on visual approach to run through the checklist that confirms their location [source: Smith].

We won't know the full story on the Dreamlifter mix-up until the U.S. National Transportation Safety Board (NTSB) completes its investigation, but we do know that, in Wichita's case, the confusion has occurred before, especially in bad weather. In fact, one former Boeing employee told the Wichita Eagle that the company used to brief pilots about the problem, although he added that most pilots twigged to the mistake before landing [source: Plumlee and McMillin].

Of course, Wichita isn't the only city where mistaken landings happen. It's not even the only one where they've happened multiple times.


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