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Airlines are running out of 4-digit flight numbers

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Re: Airlines are running out of 4-digit flight numbers

#451

Post by Idiot211 »

madcaptenor wrote: post #311
ryukoposting wrote: post #259

Earlier quoted context omitted.

I'm certain each flight has its own completely unique ID buried somewhere in a database. But, shorter codes can be spoken into a radio faster and with lower probability of misinterpretation - both critical features for air traffic control. Those shorter codes will necessarily be reused, it's just a question of the time interval between re-uses of any particular code. I faintly recall seeing two Southwest flights from…

Short flights out-and-back from a hub can have the same number on the two legs. An example is AA 1992, which today departs PHL 3:06 PM, arrives ATL 5:17 PM, departs ATL 5:57 PM, arrives back at PHL 8:05 PM. (All times US Eastern.) My mother recently had an itinerary where both her flights were this flight - the PHL-ATL leg on a Sunday and the ATL-PHL leg on the following Saturday. (It looks like as of Tuesday AA 1992…

To be fair, this problem is semi-solved by European airlines by having callsigns like BAW44W.

Which uses the last 2 numbers of the flight number, and an alphabetical character. BA use this on a lot of transatlantic type flights where delays etc can be an issue.

Re: Airlines are running out of 4-digit flight numbers

#452

Post by indus »

Green-Man wrote: post #386
indus wrote: post #284

In 2010, Indian railways switched from a four-digit numbering system to five digits. They were running out of train numbers. Indian railways today operates 13,000 trains daily. There is a PDF that talks about the problem, the solution, exceptions, and a rollout plan. One fine day, IT systems seamlessly transitioned—-took some time to wipe the old numbers from passengers memories.

I looked up the nickname of the author of the commentary. Now I feel recursion is still running inside my brain

oh man! such a comment ;-)

Re: Airlines are running out of 4-digit flight numbers

#453

Post by aworks »

aworks wrote: post #420
thaumasiotes wrote: post #115

Earlier quoted context omitted.

> I'm pretty sure they want to keep flight numbers short because that's how passengers identify their flight. That wouldn't describe any passenger I've ever known, including myself. We identify our flight by destination and departure time. Airport boards are conveniently sorted by departure time. In case of a tie, I'd fall back to airline, also indicated separately on the board, but a tie over destination and departu…

In the 1980s, I once boarded a Republic flight from Detroit to Houston. Unfortunately, the flight I paid for from Detroit to Houston was a different (and direct) one. In Detroit, there was confusion on the plane as someone else had the same seat assignment but they found me another seat. They finally figured out I was on the wrong plane when we landed in Memphis. I was bounced off a full flight and had to wait 8 hour…

I mostly remember being stuck in Memphis ~40 years ago...

I don't remember what boarding passes looked like then. I assume detachable, printed boarding pass stubs were not yet being used.

I actually started the trip in Grand Rapids, MI where I presumably checked in at the main counter, and received seat assignments for two flights (GRR => DTW, DTW => HOU (Hobby or International). I probably checked a garment bag.

I don't remember the circumstances in Detroit but somehow ended up boarding the Memphis/Houston flight rather than the Houston flight. I don't know if I was at the wrong gate because I read the wrong flight on the monitor, saw a gate with a sign that included Houston, or some other reason. I don't remember any boarding announcement so maybe I had a tight connection.

I then handed my boarding pass to the gate person and boarded the plane. It wasn't until there was a seat conflict in Memphis when a flight attendent noticed my boarding pass did not match this flight.

I suspect it was a one-stop flight rather than a hub-and-spoke connecting flight like I had in Detroit. Maybe the original signage listed both airports. I did not get off the plane in Memphis until the next set of passengers came on and someone said they had my seat. Then finally, an employee finally noticed I was on the wrong flight.

I do remember airline employees discussing that it was a full flight and they considered having someone on an employee ticket give up their seat but in the end they booted me off.

My luggage arrived ahead of me.

Re: Airlines are running out of 4-digit flight numbers

#454

Post by tyingq »

ungamedplayer wrote: post #432
tyingq wrote: post #243

Earlier quoted context omitted.

>Whenever I hear that any IDs could be "recycled", I make a mental note to replace the person making such a proposal from all teams that I am involved in. I understand the sentiment, but in this case, someone is trying to solve for constraints they didn't invent. Flight number was fixed to 4 digits long ago and propagates out to a lot of different systems, many not in the same company as the airline, also many being…

Sounds like they are artificial constraints. I'm sure it sucks that it's "four digits only" but the air travel industry isn't immune from changing specifications. I believe ancient cultures called this software maintenance.

Yes, they've changed specifications before. Y2K being one example. Artificial seems strong though. I was trying to explain that a single airline can't fix this solely in-house. It would have to be an industry change across airlines, government agencies, third party vendors, etc. So it's not artificial, but it's not trivial either.

Re: Airlines are running out of 4-digit flight numbers

#455

Post by tyingq »

whizzter wrote: post #449
kelnos wrote: post #380

Earlier quoted context omitted.

It's not ego, it's marketing, loyalty, and customer comfort. Passengers don't want to see "multiple airlines" in their itinerary. They wonder if the baggage allowances are the same, and if those bags will make it all the way to the final destination. They wonder if they'll get miles on their "main" airline for the whole trip, or if it will be broken up between different loyalty programs. They wonder if the connection…

That sounds a lot like party-line arguments honestly, maybe rooted in 1960s issues 1: If I've paid on a non budget airlines _site_ (like Lufthansa,Air France,SAS,etc) and then see another livery on the plane I'm boarding that I'm not expecting I'd be slightly disappointed and lose trust in the selling airline regardless of any codeshare. If I see when ordering on the SAS site that the second leg on a route is handled…

> Baggage allowance is clearly stated when ordering tickets online from a serious airline

Sure, though, those fields (marketing carrier/flight + operating carrier/flight) drive things like what the kiosk or agent charges you. Say you booked on AA, but part of your travel was a codeshare on BA. That integration is how all those terms and conditions get followed. Why you pay the AA $50 overweight charge for your big bag rather than the BA $65 charge. Similar for refunds and loyalty programs. Take loyalty...the points aren't awarded until you fly, via a "lift" message. And if it doesn't have the right marketing carrier + flight number, that "lift" message doesn't get processed.

Yes, it's old and rooted in the 60's. And yes, it's got issues. Nobody is selling it as elegant. Just that it serves useful functions now, and that it's ensnared in enough separate internal and external systems that replacing it with something better is not trivial.

Re: Airlines are running out of 4-digit flight numbers

#456

Post by FeepingCreature »

everforward wrote: post #416
FeepingCreature wrote: post #234

Earlier quoted context omitted.

I don't really understand. My router gives me an IPv6 address...

Do your devices behind the router get IPv6 addresses, or just the router itself? I wouldn't be super surprised to see routers getting IPv6 addresses and doing a 6in4 NAT, so devices behind the router get IPv4 addresses. I would be surprised and impressed if your devices were actually getting public IPv6 addresses. IPv6 can be kind of unwieldy, but the bigger issue to me is that old and/or very cheap clients (like bar…

edit: Okay I thought it did but apparently my router doesn't assign publically routable IPv6 addresses by default. I found a setting that would enable this though. Gonna leave it off for security reasons, but it's just a toggle, so still seems pretty easy. Also my local interface apparently has an (unrouted) ip in the same subnet as my router's public address, and I'm not sure how it got it.

Re: Airlines are running out of 4-digit flight numbers

#457

Post by ryukoposting »

lisper wrote: post #363
ryukoposting wrote: post #259

Earlier quoted context omitted.

I'm certain each flight has its own completely unique ID buried somewhere in a database. But, shorter codes can be spoken into a radio faster and with lower probability of misinterpretation - both critical features for air traffic control. Those shorter codes will necessarily be reused, it's just a question of the time interval between re-uses of any particular code. I faintly recall seeing two Southwest flights from…

> Flight 1555 from ORD to BWI departs at 4PM today, and flight 1555 from ORD to BWI departs at 4:20PM tomorrow. Why do you find that remarkable? That's just the same flight departing at slightly different times on two different days.

Like I said, 1 day of separation doesn't seem like anything remarkable, but it begs the question: do the numbers get reused for the same flight on shorter intervals than a day? If so, when? Even more interesting, why?

And, technically, the two flights 1555 in my example aren't the same - one departed at 4:00, and the other at 4:20. Both flights were on-time, so this wasn't a scheduling issue delaying one or the other. 20 minutes isn't a big difference, but it is still a difference. How big does the difference have to be to make Southwest assign two different codes?

Even more philosophically asinine, what do we even mean when we say two flights are "the same?" If Southwest thinks those two flights are the same, then clearly departure time only matters within a certain fudge factor. So that's one part of the picture. Do the make and model of plane need to be the same? Does it need to be the very same physical airplane?

Are any of these questions important to my everyday life? No! Are they interesting? Absolutely!

Re: Airlines are running out of 4-digit flight numbers

#458

Post by lisper »

ryukoposting wrote: post #457
lisper wrote: post #363

Earlier quoted context omitted.

> Flight 1555 from ORD to BWI departs at 4PM today, and flight 1555 from ORD to BWI departs at 4:20PM tomorrow. Why do you find that remarkable? That's just the same flight departing at slightly different times on two different days.

Like I said, 1 day of separation doesn't seem like anything remarkable, but it begs the question: do the numbers get reused for the same flight on shorter intervals than a day? If so, when? Even more interesting, why? And, technically, the two flights 1555 in my example aren't the same - one departed at 4:00, and the other at 4:20. Both flights were on-time, so this wasn't a scheduling issue delaying one or the other…

I've seen situations in the past where the same flight number referred to multiple flights between endpoints that had no apparent relationship to each other. I've also seen a single flight number refer to a flight from A to B to C, but used a different aircraft to get from A to B than from B to C. I can't find any examples at the moment though so maybe the airlines have stopped that particular insanity.

Also, airlines regularly make minor tweaks to their schedules. It's possible that what you saw was one of those tweaks taking effect.

Re: Airlines are running out of 4-digit flight numbers

#459

Post by anonfordays »

defrost wrote: post #77
anonfordays wrote: post #30

Earlier quoted context omitted.

Guess I wasn't clear. Yes ownership isn't essential but does make you more inclined to object to perceived negatives. In China the state owns the land, not the municipalities, nor private parties, so even if you live there you don't have much of a say. The state makes plans at such a large scale. This is why the Chinese are so efficient at building high speed rail, there aren't smaller municipalities, property owners…

> In China the state owns the land, not the municipalities, nor private parties How do you explain nail houses in China then? https://www.theguardian.com/cities/gallery/2014/apr/15/china... Any chance your bold assertion is something you just pulled out of the air?

>How do you explain nail houses in China then?

A private entity trying to buy a private entity is not the same as the Chinese government taking or using the land they, the state, owns:

"According to the Constitution, land in cities is owned by the State; land in the rural and suburban areas is owned by the State or by collectives. (Constitution, art. 10.) Although individuals cannot privately own land, they may obtain transferable land-use rights for a number of years for a fee."[0]

Any chance your bold assertion is something you just pulled out of the air?

[0] https://blogs.loc.gov/law/2015/03/chinese-law-on-private-own...

Re: Airlines are running out of 4-digit flight numbers

#460

Post by philjohn »

bloak wrote: post #232
philjohn wrote: post #209

Earlier quoted context omitted.

I still love the bit of book trivia that since 13 digit EAN's start with a country code, you can convert an ISBN-10 into an ISBN-13 by prepending it with the code for "book land" - 978. (I worked on Library Management Software for 6 years).

You also have to recompute the check digit, of course, for example: 0131103628 -> 9780131103627

Ah yes, you're indeed correct - I forgot that :D

I also used to know what most of the MARC 21 (library interchange format) codes stood for ... but that has now been purged from the memory banks ... except 245 $c - statement of responsibility https://www.loc.gov/marc/bibliographic/bd245.html

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