Land and Hold Short

If you were building a mapping application that could show only (say) 20 airports on the screen at once at any given zoom level, how would you decide which airports are most important, using only publicly-available data sets? Here are some possibilities:

• Points for being in the list of the top 100 passenger airports.
• Points for having an ICAO code.
• Points for having an IATA code (rarer, so more points than an ICAO code).
• Points for each localizer and glideslope (since they’re unambiguously associated with the airport).
• Points for having a TAF.
• Points for having a METAR.
• Points for each long, paved runway.

These are all easy to measure, but I’m not sure that they capture enough of what makes an airport important for mapping purposes. Really big airports often cluster around urban areas — think of JFK, EWR, and LGA around New York, or LHR, LGW, and LCY around London. These are all busy airports, but they’re very short drives from each other (traffic permitting), so perhaps they don’t have the same kind of importance on a map as the main airport in a smaller country, the only airport serving an isolated community or an island, etc.

I’ve done some experimenting trying to measure isolation: for example, I’ve tried limiting the map to one airport in each 30×30 deg square (world level) or 10×10 deg square (continent level), but the map still ends up with huge clusters of airports in the U.S. and Western Europe and none in most of the rest of the world, and even a 10×10 square means that Toronto’s and Montreal’s main airports won’t show up (same square as JFK and EWR). What would Google do?

The online edition of Sports Illustrated (via CNN) has a story about the NTSB report on the Liddle crash. There’s nothing surprising in the report — the rough outline of the accident chain was obvious early on — but the story does mention an interesting side issue: Liddle’s Major League Baseball benefit package included USD 1M life insurance, but with an exclusion for an aircraft accident where the insured is “acting in any capacity other than as a passenger.”

The SI story talks about figuring out who was at the controls during the crash, but that’s not the point. Even if someone were to discover a photo showing Liddle’s instructor, Tyler Stranger, at the controls just before the crash, Liddle could still have been acting as pilot in command during the flight; if so, he would have continued in that capacity even when Stranger was at the controls. Likewise, if he were paying Stranger as his instructor during the flight, then he was acting in the capacity of a student, not a passenger, no matter who was at the controls or who was PIC.

I’m no fan of aviation exclusions in life insurance (my own insurer agreed not to put one in), and I don’t want to cheer the insurer on in the upcoming lawsuit, but there’s an important point to be made here about flying. As other aviation bloggers have pointed out, its the responsibility for a flight, not the physical manipulation of the controls, that defines a pilot in command. Two centuries ago Nelson’s Royal Navy, captains rarely, if ever, touched the wheels of their ships — that was the helmsmen’s job — but nobody doubted that they were captains, all the same.