Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Airlines are running out of 4-digit flight numbers

viewfromthewing.com

Post reply on HN
Print view View original

421–430 of 461 posts

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

#421

Post by [deleted] »

ReptileMan wrote: post #310
zeagle wrote: post #80

Clearly the successor solution is to use eight groups of four hexadecimal digits each, separated by colons. Then each individual seat and peanut could be addressed to it's final destination. More seriously the solution suggested of giving the 3 companies other unused prefixes like D* U* and A* to use with their codeshares and non rev flights to start seems the easiest.

Roughly 20 years ago a network engineer I worked with said - "We took a look and IPv4 had everything we want and need but the address space". Why the committees didn't just made it 128 bit and be done with it is beyond me.

[deleted]

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

#422

Post by pdx_flyer »

jll29 wrote: post #227

> Here’s the full answer, along with how they triage the problem – for instance by assigning the same flight number to more than one flight a day (although that means they need for it to be flights that would never both be in the air at the same time, such as where the same plane is used and can’t reasonably be substituted) This sounds like it's calling for trouble! Whenever I hear that any IDs could be "recycled", I…

British Airways frequently has flight in the air at the same time with the same flight number. For ATC these are typically identified with a letter at the end of the flight number like BA 123E or BA 345Y.

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

#423

Post by chgs »

the_mitsuhiko wrote: post #274
chgs wrote: post #214

Earlier quoted context omitted.

AF296Q was a flight which crashed in 1988 They are rare though

They are not very rare. Letter suffixes are very common in Europe to avoid potential ambiguity. However they do not change the actual flight number portion. https://www.flightradar24.com/blog/clearing-up-call-sign-con...

Call signs have letters sure, but while I think I’ve seen letters on departure boards they are rare.

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

#424

Post by indus »

akpa1 wrote: post #356
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.

Do you have a link to the PDF?

I need to fish the exact one but this is the public cover of that

https://indianrailways.gov.in/railwayboard/uploads/directora...

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

#425

Post by delta_p_delta_x »

andrewstuart2 wrote: post #410
delta_p_delta_x wrote: post #292

Earlier quoted context omitted.

> I'm certain each flight has its own completely unique ID buried somewhere in a database There is. It's called the Globally Unique Flight Identifier (GUFI), and it's essentially a UUIDv4[1]. [1]: https://docs.fixm.aero/#/general-guidance/flight_identificat...

Please tell me it's pronounced "goofy."

It actually is. I interned at a civil aviation authority where I had to implement a GUFI generator, and they all pronounced it 'goofy'.

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

#426

Post by kiwijamo »

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.

Let me try to explain: On routes with high frequency flights, airlines will generally issue a different flight number for each unique departure time to a particular destination. E.g. YY500 departing at 9am to LAX on Mon/Wed/Fri and YY502 departing at 9:05am to LAX on Tue/Thu/Sat/Sun. It's unusual to have the same flight number YY500 apply to either the 9am or 9:05am flight. But if there is no collision (i.e. 9am and 9:05 doesn't operate on the same days) it seems a sensible optimization to reuse the flight numbers. It's just not very common practice in the airlines I regularly fly with (NZ, QF, JQ etc) so can understand why it seems remarkable. Air New Zealand for example only 'reuses' flight numbers for their flagship (e.g. NZ1, NZ2, NZ3, etc) flights whereas their NZ5xx NZ6xx series flights for high frequency domestic flights generally are unique in respect to departure times and rarely do they reuse a flight number for a different departure time.

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

#427

Post by Aeolun »

taneliv wrote: post #413
tivert wrote: post #389

Earlier quoted context omitted.

>> I'm certain each flight has its own completely unique ID buried somewhere in a database > There is. It's called the Globally Unique Flight Identifier (GUFI), and it's essentially a UUIDv4[1]. Great, step one cleared. Now have all the legacy systems everywhere that use 4-digit flight numbers been updated or replaced?

Like the mechanical displays at various airports across the world pictured in the article? Overall seems like a project of huge size and somewhat unknown reach. Not my domain, but I would imagine all kinds of ground support systems to have the four letter flight numbers baked deep into their assumptions. And not only direct support like fuel, cleaning, work shift scheduling, but also logistics systems for cargo, mili…

So we’re already too late by about 20 years to fix the issue properly.

Undoubtedly we’ll push the issue forward for another 10 years before realizing that the next best time to start was today :/

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

#428

Post by delta_p_delta_x »

tivert wrote: post #389
delta_p_delta_x wrote: post #292

Earlier quoted context omitted.

> I'm certain each flight has its own completely unique ID buried somewhere in a database There is. It's called the Globally Unique Flight Identifier (GUFI), and it's essentially a UUIDv4[1]. [1]: https://docs.fixm.aero/#/general-guidance/flight_identificat...

>> I'm certain each flight has its own completely unique ID buried somewhere in a database > There is. It's called the Globally Unique Flight Identifier (GUFI), and it's essentially a UUIDv4[1]. Great, step one cleared. Now have all the legacy systems everywhere that use 4-digit flight numbers been updated or replaced?

My understanding is that air traffic control is extremely computerised even though direct control is still done over analogue VHF voice radio. The flight numbers are essentially only human-facing (both passenger flight numbers, and ATC callsigns). When flights are handed off between different stations or different flight information regions, their computer representations must conform to the Flight Information Exchange Model (that's the FIXM in the website I linked above).

It's a very top-down initiative by ICAO and all the large aviation authorities—quite unlike the rest of the software development industry.

Frankly speaking ATC is the only thing that really matters in the context of flight safety—ticketing, terminal operations, etc don't (and don't need to) deal with FIXM.

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

#429

Post by Aeolun »

kelnos wrote: post #380
whizzter wrote: post #329

Earlier quoted context omitted.

Seems to me like an ego issue honestly since the article points out that a large part of the bloat is from codesharing, using the actual operators code feels like an obvious solution unless egos are too fragile.

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…

Codeshares would solve those problems just as well without a separate flight identifier for every airline.

Honestly codeshares suck regardless. If I chose an airline it’s because I did not want to deal with their annoying competitors.

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

#430

Post by Aeolun »

ViktorRay wrote: post #331
jll29 wrote: post #227

> Here’s the full answer, along with how they triage the problem – for instance by assigning the same flight number to more than one flight a day (although that means they need for it to be flights that would never both be in the air at the same time, such as where the same plane is used and can’t reasonably be substituted) This sounds like it's calling for trouble! Whenever I hear that any IDs could be "recycled", I…

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. This sounds pretty messed up to me. Someone makes a suggestion or throws out an idea you don’t like so you’re gonna essentially cut them out of your professional life or even fire them? Am I reading this right?

I feel like it’s completely understandable. There’s a certain kind of person that thoughtlessly makes comments like this, and it extends beyond just ID’s. You do not want them on your team.

In some instances it’s simply because they are extremely junior and they can be taught, but most instances it’s because they have a habit of shortcuts.

Now that I think of it, this would make a great interview question.

Post reply on HN