Hi all, if you looked a little bit into boarding pass barcodes you might know that at the end of the common data there's an airline specific field. Out of pure curiosity (I don't think there's anything to be gained from this), I'd like to figure out what they're stuffing in there . The data is too short to really contain sensitive information, so personally I feel comfortable posting it here, and hope some of you might join in, but use your own judgement.

NB: if you post, replace spaces with dots (or something else, if you get a dot in there). The forum combines multiple spaces into one. Not doing this will confuse/mangle any effort to understand these bits!

So far, I have seen, at the end of the barcode:

* "*30600000K09..LHG...." - I get this on most of my LH/LX/OS flights. LHG matches my status (Senator).
* "*30601023K09..LHG...." - got this from OS on getting rebooked by Austrian, on a delayed Austrian flight, to another Austrian flight, but originally was LH booking.
* "*30601023K09........." - got this from OS/LH on the same rebooking as the previous one, where they did in fact "forget" my status for whatever reason. Unlike above, this was a LH flight.
* "*30601019K0A02LHGFASTR" - got this from TK on a regular business class booking, nothing special happened that I'm aware of

So far, my theory is - all guess of course:
* '*' - 1 character ID or separator. Might indicate Star Alliance, but might also just be "here starts different data"
* '3' - 1 character possibly version number for the data. The standard parts in the barcode do this too (e.g. version "8" is current on the main passenger detail block).
* '06' - 2 character possibly a sub-block length. Again the other bits in the barcode use 2-character length indicators to make blocks of data, and this lines up with the 09 and 0A later.
* '00'/'01' - 2 character, no clue - that this is a 2-character field is also just a guess based on the numbers.
* '000'/'019'/'023' - 3 character, no clue - again, even the length of the field is a guess.
* 'K' - no clue. But if the 06 is a sub-block length, that sub-block ends after the K.
* '09'/'0A' - 2 character possibly a sub-block length again. 0A is hexadecimal 10, as is done in other places in the barcode. And it lines up to the end of the data! Smells like a pretty good guess.
* ' ' / '02' - 2 characters probably, no clue.
* 'LHG' - quite obviously the *A status airline and level.
* spaces / 'FASTR' - not sure if it's 'FAST' + 'R' in 2 fields or 1 field with 'FASTR' but I believe this might be related to security or immigration fast track bits. NB: the non-airline-specific barcode data already contains a Y/N fast track indicator, it makes little sense to repeat it here and LH only having spaces kinda confirms that.

Anyway if we get a few more of these, maybe we can divinate some meaning!

Sometimes I do OLCI and save the mobile pass then also receiving a printed BP. If you happen to have a QR code for the same flight, did you try to compare it with the barcode? Maybe they're mapping QR code data into barcode - some sort of transformation?

"Unfortunately" I did already compare with the QR code in the app - it's identical, except for the "source of boarding pass issuance" field (O for ticket counter, M for mobile). That field is in the standardized part & you can (with a little effort) find the specification with google.

(unfortunately because no further information or hints from there...)

Got another one from a colleague (not posting because it's not mine) - it looks almost the same as my 3rd one, but it has "FBAG" where the TK one has "FASTR". He didn't do anything special with baggage, we couldn't come up with anything we could tie to it. (Particularly he doesn't have any status currently, so it can't be priority baggage handling. It was a single leg trip, no SCON, no transfering, ...)

At the end did your friend drop luggage?

Dug up a few old boarding passes:

* '*30601000K09..LHG....AC.813........Y..........' - 2x on Air Canada issued BPs. Weirdly, AC813 wasn't involved as a flight at all, this was AC573 and AC8846 SFO<->YVR
* just nothing on an Eurowings flight ("SEN/SMART" printed on)
* '*30601001K09.........' a whole bunch of times when either I didn't have status yet or it was lost
* '*30601001K09..LHS....' a whole bunch when I had LH FTL
* '*30600000K05..LHS' exactly once, on a HAM->FRA BP. Note this is incredibly valuable because it seems to confirm the "05" being a length field. The thing is missing the 4 spaces at the end!

I suspect that the 01 after the 06 is the number of pieces of checked baggage, and the 000K 001K 019K 020K might be baggage weight. The 001K is predominantly on older BPs, maybe it was just a placeholder/the value wasn't wired in yet. I had 2 pieces of checked baggage exactly once in my life, I need to check if I can still find the printed BP for that (I always get printed BPs.) The mobile/web/mail BPs wouldn't normally show checked baggage since they're issued before you drop your bags...

(Need to ask my colleague about the luggage, currently travelling myself so it'll be a bit.)

From recent A3 flights printed on the same BP. There was a piece of luggage - according to the luggage tag it was 10kg.
*30600000K09..TKG

From a TP flight - operated by RE
*30601018K09.TKGKEYC

From a TK flight
*30600000K0A02TKGFASTX

From an LX flight
*30602018K09.TKG....

No need to reverse engineer, IATA reso 792 specifies what belongs in the various fields of the BCBP. As the bar codes are not (yet) encrypted nor signed, you could in theory add fast track priviledge(s) to the code as the fast track access scanners often just look for that field and don't check with the master to allow you access.

More here: https://www.iata.org/contentassets/1...version-7-.pdf

I'm entirely aware - this is about the "For individual airline use" (Field 4) part of the BCBP. What is encoded in that part is not specified by IATA and AFAIK not publicly available anywhere. It starts with *306 on all *A boarding passes I've seen.

United's QR codes given as example in the PDF do in fact contain a signature, but I don't know whether that's in active use.

If you got the spaces right, my "length field" theory doesn't work (first one would be missing 4 spaces at end, 2nd and 4th one would be missing 1 space before TKG.)

But you have FASTX where I had FASTR, that might be a hint that this is "FAST" + "X/R" as 2 separate things. It's also starting to feel like a real mystery with whatever "FAST" "FBAG" "KEYC" could be

On the plus side I'm gonna be flying AC in about 10 days, their ultra long extra data seemed interesting too. Wonder if I'll get "AC 813" again

After reading your message I re-scanned them and copy pasted more carefully to ensure spaces are kept during the process. Please find the updated ones below. Seems like your theory is still valid.

*30600000K09..TKG....

*30601018K09..TKGKEYC

*30600000K0A02TKGFASTX

*30601015K0A02TKGFASTX (from another TK flight which wasn't there in the first post, I was upgraded to J, also had 15kg of luggage)

*30602018K09..TKG.... (I had two pieces of luggage, one of them was interlined to a TK flight next day and there're high chances it was 18kg, the other piece taken on hold because of crowded cabin or *G perk)

FBAG can be luggage related. Maybe it refers to free baggage allowance? No idea about KEYC and very curious about it.

TK uses their own PSS called Troya. They have a different set of codes altogether:

https://jonskaas.com/images/PDF/ED31...1_08062020.pdf