Tuesday, February 11, 2014

Landing at the wrong airport

Mistaking one airport for another is more common than we (or at least I) thought. This happens mostly in areas where there are multiple airports in proximity, such as the San Francisco Bay Area's South Bay where Moffett Field and Mineta San Jose International are separated by only ten miles. (Huge kudos to the Associated Press for doing the investigative journalism behind this story.)
In nearly all the incidents, the pilots were cleared by controllers to guide the plane based on what they could see rather than relying on automation. Many incidents occur at night, with pilots reporting they were attracted by the runway lights of the first airport they saw during descent. Some pilots said they disregarded navigation equipment that showed their planes slightly off course because the information didn't match what they were seeing out their windows — a runway straight ahead.
My first instinct was to fault the pilots for not heeding their instruments, but then I considered how untrustworthy GPS devices have proven in my own wanderings. Most of the time they work well, but occasionally they seem to lose their electronic minds; it seems possible the same problem might apply even to presumably more sophisticated jet navigation systems.

I'm not thrilled by the idea of making pilots even more dependent on instruments. Anyway, it seems to me that airports could deploy a lower-tech solution: a big, bright sign that displays a visual cue unique to the airport and the approaching flight. It could be a colored symbol, e.g., a green asterisk, although colors could be problematic for the color-blind (are pilots allowed to be color-blind?). Or it could be as simple as the flight number, though there might be safety concerns about flashing the number of the approaching flight to everyone in visual range of the airport. Whatever the cue, it should be both unique and easy for the pilot to check; this leaves out one of the computer scientist's favorite solutions, a random string of symbols, since that would be difficult to verify quickly. Ideally, the symbol would not be difficult to describe, either, given the language issues that surround international flights.

The protocol would be for the pilot and the flight controller to agree on the visual signifier, and for the pilot to confirm the signifier is being displayed next to the runway. Geographically proximate airports would coordinate so that they didn't share visual cues.

Air traffic controllers already have a lot to do and requiring them to coordinate a unique landing cue for each aircraft might be more than they can handle. However, that doesn't seem to me an insuperable problem: I imagine that controllers' landing procedures can be altered so as to free them up enough to carry out this additional task, possibly by shrinking their areas of responsibility and adding more controllers. It seems to me that the possible danger of landing at the wrong airport — one where the runway was undergoing maintenance, for instance — justifies the cost and inconvenience to airports, air traffic controllers and flight crews.

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