Airline flight numbers have become increasingly complicated as the industry has matured. Three-digit flight numbers are the norm, and many of the flights we see these days have four-digit flight numbers. A standard joke is that the FAA (or Union) has recently done a study that shows that five out of four pilots (or controllers) is dyslexic; these four-digit flight numbers seem to enhance that quality and even invite mangling. Skywest and the recently-departed Jetlink have been the leaders at LAX. A few recent Skywest examples: 6525, 6552, 6225, 6252. Also: 5548, 5484, 5448, 5844. Jetlinks were even worse, as they used flights in the 7600s, 7700's, and 7800s. Sixes and sevens, although not looking anything alike, have a mysterious tendency to get interchanged when being spoken. Maybe it's the alliterative quality, but it doesn't happen near as much with fours and fives.
The hub-and-spoke scheduling system, combined with regional airline partners, is probably to blame for the increased complexity. A lot of routes are out-and-back flights, with alternating even/odd flight numbers; for instance Continental's service between IAH and LAX: flights into LAX are odd numbered (495, 595, 795), while the return flights are even (394, 594, 794). It is quite possible to have both on frequency at once, as one arrives and the other departs. When this happens, the opportunity for pilot or controller discombobulation escalates: It regularly happens that the pilot of one will answer radio calls for the other. A couple of variations: Numbers using fifty and sixty, which sound an awful lot alike on our low-fidelity radios. A particularly flagrant example, again from Skywest: 5516 and 6516, closely followed by 5512 and 6512. These two pairs show up around the crack of dawn most mornings, when nobody is at their best: The controllers are struggling to the end of their mid-shift, while the pilots aren't really even awake yet.
The other variation is numbers such as 69 and 169. WARNING - Old war story coming up! I actually saw a close call created by the confusion created between two United aircraft using these flight numbers: One took the clearance meant for the other, and the mistake didn't become apparent until it was about a mile from landing on the wrong runway - which was already occupied with a 747 waiting to depart AND two other aircraft crossing downfield. It was fairly late one night a few years ago, and I was the tower controller for the south side of the airport (runways 25 left and right). Arrivals were being sent to both runways, and there was a steady flow of departures as well. United 69 was assigned runway 25 right, and landed without incident. About ten or twelve miles behind was United 169, who was assigned runway 25 left. His data tag said runway 25 left, and I cleared him to land on runway 25 left. Meanwhile I had a Qantas 747 line up on runway 25 right, holding for departure while a couple of previous 25 left arrivals crossed the runway enroute to their gates. It was already a bit of a squeeze play, as I had to fit my Qantas in between two other aircraft departing from the north complex - and that controller had arrivals for both of his runways as well. In addition, I had to get my arrivals across the inboard runway so that there would be room for the next arrivals to exit their runway (as I mentioned, this was several years ago - before the space between the south side runways was widened and the center taxiway developed - there wasn't much room between the runways, and the Local controller had to be careful about not accumulating aircraft between the runways, lest subsequent arrivals have no where to get off). Anyway, I was closely monitoring the progress of my crossing aircraft on the ground radar (remember - it was about ten or eleven o'clock at night) so I could get Qantas rolling when suddenly the runway hold bars went up on 25 right. The ground radar in the tower cab, one of the main functions of which is to prevent runway incursions, is tied into the approach radar and projects what runway an aircraft is about to land on (or depart from). When it projects a landing or departing aircraft, bright hold bars are illuminated across every intersection on the display for that particular runway. These were what made me realize that United 169 was on short final for runway 25 RIGHT - not 25 left as he was supposed to be. The runways are so close together (even now) that the system only works about thirty seconds into the future; it was too late for him to move over to the correct runway, so I had to send him around. He went a few hundred feet over the top of the waiting 747 as the runway occupied alert message blared in the tower cab - a guaranteed way to make sure all eyes are looking at you!
Yet another version of callsign confusion occurs when two airlines show up at about the same time with the same flight number. This happens surprisingly often at LAX, which is served by at least fifty airlines - and several of them operate hubs here. A current example that comes to mind is United 58 and AirTran (callsign: Citrus) 58, both scheduled departures about ten minutes apart. This wasn't that big a deal until a week ago, when AirTran moved from Terminal 3 (on the north side) to Terminal 6 (on the south side, and shared with United to boot). At someplace busy like LAX this is almost unavoidable, although we do work with the airlines to change conflicting flight numbers (and thus creating flight peculiar numbers such as Skywest 16A - the new flight number for what used to be the Skywest 6516 mentioned above - but hey, it works!).
None of that, nifty though it may be, is what I meant for this column to be about: the other end of the numerical range - specifically ONE. Many airports don't have any flight ones - I don't recall any from any of my previous duty stations (MLU, MSY, MEM), and Air Force One doesn't count. Here at LAX, however, we've got at least seven flights numbered one. As I discussed above, all of these operate in the opposite direction as flight two. Most are international, but not all:
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