# Is there a mathematical formula for flight numbers? **URL:** \ **Category:** Factual Questions\ **Created:** [June 19, 2014, 5:57pm UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155 "2014-06-19T17:57:41Z")\ **Posts on this page:** 12\ **Page:** 2
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [June 20, 2014, 3:05am UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/21 "2014-06-20T03:05:46Z")
> [@OldGuy](#): > > No you can’t calculate a CT license plate number, but I was replying to the statement that “they do not indicate … any other measurement.” They do. They indicate the order in which they were issued and hence their approximate age. I still have a ### DLN plate which was issued around 1985 and transferred with two trade-ins. The fact that I see almost no other plates anywhere near that old tells me most people apparently don’t trade in one car at a dealer for another but buy a car then sell their old one elsewhere. Those are still nominal numbers though. Almost all numbering/lettering schemes have some logic built into them but it still doesn’t mean you can do math with them even though people try to all the time. I work with many such schemes as part of my job as a systems analyst and have throughout my career with many large corporations. Someone at some point figured out a brilliant plan to treat ordinal numbers like math problems and it doesn’t end well. Whole software packages are built around the schemes. It could be something like an embedded date of manufacture combined with a product code or whatever other cockamamie scheme someone wants to make up. Everything works until the company buys a competitor and they find out that their schemes cause logical duplicates and there is no way to sort them out systematically based on the data given. All of the systems fail some of the time and then they try to come up with a new scheme that will cause the same problem years later. I have redesigned systems around ill thought out nominal numbering schemes more times than I can count and I am going through two now. For some reason, people think that just because something looks like a number, you can do basic math to work things out when that is not the case at all for nominal numbers. They aren’t true numbers. They always have exceptions that break the whole concept and force you to use lookup tables to translate them. You might as well use letters or Chinese symbols because they are all the same thing logically speaking. ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [June 20, 2014, 5:46am UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/22 "2014-06-20T05:46:57Z")
> [@robert\_columbia](#): > > I think the idea behind the OP is that a flight number could be calculated based on some sort of formula that you could take and plug in the origin and destination (e.g. by latitude and longitude, some cipher conversion from the airport abbreviation (e.g. IAD), etc.), the time of day of the flight, the day of the week or the day of the month that the flight leaves, and/or some numeric id associated with the airline. Wikipedia does describe some general [guidelines](https://en.wikipedia.org/wiki/Flight_number) traditionally used to assign flight numbers. Among other things, single- and double-digit numbers have been used for premium or long-haul services, e.g. British Airways 1 used to be the morning Concorde flight to NYC. East- and northbound flights may have even numbers, with the return flight numbers increased by 1, which makes them odd, obviously. Regional and commuter flights may have four-digit numbers, as well as charter flights. These are only a few of the “rules” which the article mentions, “rules” in this case being more like “guidelines”. I notice a vague similarity to Amtrak train numbering schemes, and wonder which of the two inspired the other. ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [June 20, 2014, 5:49am UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/23 "2014-06-20T05:49:10Z")
> [@robert\_columbia](#): > > I think the idea behind the OP is that a flight number could be calculated based on some sort of formula that you could take and plug in the origin and destination (e.g. by latitude and longitude, some cipher conversion from the airport abbreviation (e.g. IAD), etc.), the time of day of the flight, the day of the week or the day of the month that the flight leaves, and/or some numeric id associated with the airline. But what would be the point of all this? It’s not like your flight number is a top secret military operation. Wikipedia does describe some general [guidelines](https://en.wikipedia.org/wiki/Flight_number) traditionally used to assign flight numbers. Among other things, single- and double-digit numbers have been used for premium or long-haul services, e.g. British Airways 1 used to be the morning Concorde flight to NYC. East- and northbound flights may have even numbers, with the return flight numbers increased by 1, which makes them odd, obviously. Regional and commuter flights may have four-digit numbers, as well as charter flights. These are only a few of the “rules” which the article mentions, “rules” in this case being more like “guidelines”. I notice a vague similarity to Amtrak train numbering schemes, and wonder which of the two inspired the other. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [June 20, 2014, 6:43am UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/24 "2014-06-20T06:43:05Z")
[QUOTE=Spectre of Pithecanthropus] Wikipedia does describe some general guidelines traditionally used to assign flight numbers. [/quote] It doesn’t say one way or the other, but I always assumed for some reason that different airlines don’t use the same numbers–that every flight number is unique across all companies. But apparently that isn’t the case. ---
**Author:** ![UDS](https://avatars.discourse-cdn.com/v4/letter/u/ecae2f/32.png) [@UDS](https://boards.straightdope.com/u/UDS)\ **Post date:** [June 20, 2014, 7:35am UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/25 "2014-06-20T07:35:32Z")
> [@guizot](#): > > It doesn’t say one way or the other, but I always assumed for some reason that different airlines don’t use the same numbers–that every flight number is unique across all companies. But apparently that isn’t the case. It isn’t the case at all. If it were, then there could only be 999 three-digit flight codes worldwide, which clearly is not the case. And not only do different airlines use the same numbers; within an airline the same number may be used for different routes (at different times). As noted above, BA 001 used to be BA’s LHR-JFK Concorde service, but at the moment it’s used for a LCY-SNN-JFK service (currently flown by an Airbus 318, which is a bit of a comedown from the Concorde). Or, different numbers may be used for the same route: EI 152 flies the DUB-LHR route, but so do EI 154, EI 156, EI 158, EI 162, EI 164, EI 166, and many others. In fact Aer Lingus devotes 14 different codes to DUB-LHR flights (and 14 more to LHR-DUB flights). You can see the impossiblity of dividing 999 codes between all the worlds’ airlines on the basis that each code is only used by one airline, when one regional European airline uses 28 codes for just one of its routes. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [June 20, 2014, 9:36am UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/26 "2014-06-20T09:36:52Z")
> [@Tim\_R.Mortiss](#): > > Sometimes they are assigned whimsically. I remember walking around at O’Hare one day and seeing Flight #711 to Las Vegas, and further down the terminal, Flight #1492 to Columbus. For a non-American, can you explain please? ---
**Author:** ![Alley\_Dweller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alley_dweller/32/430_2.png) [@Alley\_Dweller](https://boards.straightdope.com/u/Alley_Dweller)\ **Post date:** [June 20, 2014, 10:31am UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/27 "2014-06-20T10:31:40Z")
> [@bob\_2](#): > > For a non-American, can you explain please? 7 and 11 are considered lucky numbers for gamblers stemming from the fact that they are winning numbers in a dice game called [craps](http://en.wikipedia.org/wiki/Craps). Las Vegas is a US city famous for gambling. 1492 was the year Christopher Columbus first sailed the ocean blue, beginning the age of European settlement of the Americas. Columbus is a city in Ohio named for Christopher Columbus. ---
**Author:** ![IvoryTowerDenizen](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ivorytowerdenizen/32/17937_2.png) [@IvoryTowerDenizen](https://boards.straightdope.com/u/IvoryTowerDenizen)\ **Post date:** [June 20, 2014, 10:36am UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/28 "2014-06-20T10:36:44Z")
> [@OldGuy](#): > > This is not quite true if you include license plates as nominal numbers. In CT for example, we recently completed going through the sequence ### LLL. These were released approximately in order alphabetically through the letter sequences and within that in numerical order for the three digits. We bought a car when living in CT. The dealer told us he could tell when and where someone bought their car based on the plate number. Not relevant, but interesting (to me at least!). ---
**Author:** ![crucible](https://avatars.discourse-cdn.com/v4/letter/c/5f8ce5/32.png) [@crucible](https://boards.straightdope.com/u/crucible)\ **Post date:** [June 20, 2014, 10:52am UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/29 "2014-06-20T10:52:53Z")
When I explain to people that the popular game ‘Sudoku’ could just as well be played with 9 different symbols – stars, crescents, pentagrams, circles, triangles, squares, etc. – they look at me as though I were crazy. Nine different colors would work, too; or animal pictures, etc. While there may be some information derivable from a particular number assignment, flight numbers cannot be derived from the information. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [June 20, 2014, 10:57am UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/30 "2014-06-20T10:57:47Z")
> [@Alley\_Dweller](#): > > 7 and 11 are considered lucky numbers for gamblers stemming from the fact that they are winning numbers in a dice game called [craps](http://en.wikipedia.org/wiki/Craps). Las Vegas is a US city famous for gambling. > > 1492 was the year Christopher Columbus first sailed the ocean blue, beginning the age of European settlement of the Americas. Columbus is a city in Ohio named for Christopher Columbus. Thank you. To me, 711 is an American chain of small stores. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 20, 2014, 1:55pm UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/31 "2014-06-20T13:55:13Z")
> [@](#): > > When I explain to people that the popular game ‘Sudoku’ could just as well be played with 9 different symbols – stars, crescents, pentagrams, circles, triangles, squares, etc. – they look at me as though I were crazy. Nine different colors would work, too; or animal pictures, etc. In fact, my nieces have a toy/game that is precisely that: Sudoku played with little plastic animal tokens of various species and colors. ---
**Author:** ![OldGuy](https://avatars.discourse-cdn.com/v4/letter/o/3bc359/32.png) [@OldGuy](https://boards.straightdope.com/u/OldGuy)\ **Post date:** [June 20, 2014, 10:35pm UTC](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155/32 "2014-06-20T22:35:24Z")
> [@bob\_2](#): > > Thank you. To me, 711 is an American chain of small stores. That’s because those stores originally were open from 7 a.m to 11 p.m. [Previous page](https://boards.straightdope.com/t/is-there-a-mathematical-formula-for-flight-numbers/691155.md?page=1)