Aircraft do not have a singular unique identifier that is time invariant.
While it is true that aircraft have serial numbers issued to their airframe, by itself, aircraft serial numbers are not unique.
The only unique identifier for an aircraft across its lifecycle from production to end of life is a combination of the manufacturer, make and serial number.
I know this because I am on (for better or worse) the patent that involves defining that as a unique identifier for aircraft.
The combination of ICAO aircraft type designator + serial number approximately is the most permanent identifier for an airframe - and even then - if an airframe is modified significantly enough that it no longer is the previous type - even then this identifier can change.
Personally, it boggled my mind that something as big as an aircraft did not have a simple time invariant unique identifier.
P.S. For those who might ask - aircraft registration numbers are like license plates, so they change - tail numbers can be ambiguous and misinterpreted depending on what is painted on the aircraft where, and ICAO 24-bit aircraft addresses are tied to ADS-B transponder boxes, which technically can be moved and reprogrammed between aircraft also.
Go work at a big company. The patent lawyers come around and ask what you've been working on, and a month or two later, your name's on 10 patents, none of which make any sense whatsoever. If you're very lucky you might get a dollar bill for each.
For a while at google you would get $5k per patent submission and $10k for each approved(?) one. Given how easy it was, I could have matched my annual salary. It's depressing how easy it is to get a system architecture (unimplemented) patented at bigco.
When I was at Microsoft, years ago, it took more effort to avoid having my name end up on a patent than I'd have had to exert if I'd actually wanted one.
You burrow this simple idea in pages and pages of obfuscated tedium, and that's good enough that everyone is happy. Patent office gets their fee, lawyers get paid, company can say it has a supercharged patented innovation.
I was wondering the same thing. I've had to derive unique identifiers from hundreds of different data sets over the years. What makes it special when it's a plane?
> And the solution is almost always “model, make, and serial number.”
If you've ever spent time in old car forums, you learn that even this isn't enough because of production-line sloppiness.
Serial number re-use is rare, but it happens. Usually because a product had something detected that resulted in remanufacturing, but sometimes other things slip.
I know about systems who had two types of serial numbers which ought to be the same, but weren‘t because they had been programmed at different eol stages, when daylight savings time kicked in. One of the system run in utc the other in local time. Date was part of the serial.
Noob me would have guessed the "source of truth" would be whatever identifier(s) is recorded by the insurance company. Or maybe the service and maintenance agreements.
Failing that, I would have guessed some kind of (natural) compound key derived from the transfer(s) of ownership (Airplane Purchase Agreement? Bill of Sale?) noting the unique major components like airframe, interior, and engines? And maybe wings?
I'm only joking a little. Funny thing, surnames aren't actually that old for Europeans. Most of history there'd be maybe two people with the same name. They solved it back then very much the same way we solve it now.
Funnily enough, my "full id" (full name, city, profession plus year) isn't unique to me unless you add a date of birth.
Maybe it's not unique with a date of birth either, but statistically it should be.
It's a regional thing, but roughly translates to "John Smith, programmer from NY, born 1995"
Serial Number = was supposed to be what order the things were made in (e.g. the number of the serial order), but this is often obfuscated or often repeats [1].
In cars, make would be like Ford. Model would be like Focus, serial number would be VIN (vehicle identification number - in cars, those are generally unique!).
Ford Focus + VIN, basically.
There is a theoretical concept of a unique identifier for everything... including people from ISO under ISO 8000.. combining a natural location identifier (eNLI)[2] and an ISO8601 timestamp - to represent "where and when a thing is considered to be born" - a point in time and space the thing is considered to come into existence.
I think the idea is called "natural person identifier" for humans.
This ID has to be assigned but I think you can see the idea at least.
I suppose this doesn't include make/manufacturer but realistically that isn't needed for uniqueness in this scheme, only as descriptive metadata for things that have one.
[1] This is related to the fact that if serial numbers were truly serial, one could estimate the rate and quantity of production which is considered sensitive information by most manufacturers. This relates to "the German tank problem" - during WWII the allies were able to accurately estimate the production of German tanks by analyzing the serial numbers off captured tanks.
> Personally, it boggled my mind that something as big as an aircraft did not have a simple time invariant unique identifier.
It boggles my mind that despite not having some sort of universal system things work as well as they do.
Aviation grew up relatively insular, and each country that had any sort of aircraft manufacturing did things their own way until fairly recently. Arguably, the first half of the history of aviation is a kind of free-for-all. The fact that we now have a globalized airline industry that mostly follows some kind of standards is the mind-blowing part to me. And I suspect if we weren't mostly down to a dozen or so manufacturers for the vast majority of airliners, even that wouldn't be the case.
Yeah but at some point countries started buying larger planes from only one or two manufacturers. At that point the manufacturers could standardize things.
The full Theseus treatment would need you to take [part of] the airframe that first plane discarded, then recertify it for use under its original serial number.
The way the Aircraft of Theseus is generally resolved is there’s a piece of metal called the “data plate”. This is the airplane as far as the FAA is concerned. I’ve been in a vintage biplane that was completely rebuilt from the data plate up. I think they got it for $40k.
It was worth it because without that, a home built airplane would have an experimental certificate and you couldn’t sell rides in it.
Does the data plate not limit the scope of what can be built around it?
In other words had Virgin Galactic built the VSS Enterprise around the data plate of a Cessna 172, would it then no longer have been an experimental aircraft?
It does limit, but I suspect a lot less for the rebuilt from ground up biplane, than for a certified for airline service aircraft (a commercial airliner).
I don't think it even matters. If what you're doing doesn't piss off any potential enforcers you're good to go. If whatever you're doing does then you're screwed (or will be tied up in court and paying tons of lawyers fees) regardless.
Engines are actually changed fairly frequently because they're a wear component on most airplanes. They are also sometimes updated to a newer version or even an entirely different manufacturer. And often it's faster and cheaper to swap in a new engine that's ready to go rather than wait for the one that's attached to be overhauled, so the same engine might see service on multiple airframes.
Most cars don't operate for >12 hours a day every day. Last time I randomly checked the flight history of a Ryanair 737 on flightradar24, it had spent over 18 and a half of the previous 24 hours airborne.
And many commercial airliners are sold without engines at all.
The operators, such as Delta, do not actually own engines on the aircraft they fly, even though they own the aircraft. The engines are rented from e.g. Pratt & Whitney along with a maintenance contract. That said, that engines are in fact installed at the factory.
It’s a requirement that the airframe and engines are sold separately dating back to the original reason why United Airlines was named.
Which is not to say that commercial jets can take any old engine. Even something like this 767 that was split between GE and P&W have specific structures related to the original engine.
Aircraft do not have a singular unique identifier that is time invariant.
While it is true that aircraft have serial numbers issued to their airframe, by itself, aircraft serial numbers are not unique.
The only unique identifier for an aircraft across its lifecycle from production to end of life is a combination of the manufacturer, make and serial number.
I know this because I am on (for better or worse) the patent that involves defining that as a unique identifier for aircraft.
The combination of ICAO aircraft type designator + serial number approximately is the most permanent identifier for an airframe - and even then - if an airframe is modified significantly enough that it no longer is the previous type - even then this identifier can change.
Personally, it boggled my mind that something as big as an aircraft did not have a simple time invariant unique identifier.
P.S. For those who might ask - aircraft registration numbers are like license plates, so they change - tail numbers can be ambiguous and misinterpreted depending on what is painted on the aircraft where, and ICAO 24-bit aircraft addresses are tied to ADS-B transponder boxes, which technically can be moved and reprogrammed between aircraft also.