WARNING: if you are going to post, redact any sensitive or personal information.

What's in your barcode boarding pass - for reference, check pg 49 http://www.iata.org/whatwedo/stb/Doc...v4_Jun2009.pdf . For reading my BP, I use the Android application PDF417 (it's a demo of a library they are trying to sell, but very polished), and it works GREAT.

So let's scan one from an AA flight a couple weeks ago and see what's in it.

Breaking out the actual data, it starts with M then the # of legs, your name (last/first space padded and/or truncated to 20 characters). So, to answer a common question - no MI

Then the letter "E" followed by your seven character PNR (space added if it's only 6).

From, to and carrier codes (3 chars each: SEADFWAA(space))

Five character flight number (the example shows a 4 digit # with leading zero + a space, e.g. 0575(space))

Date of flight (3 digit Julian day of year #)

Compartment code (I'm guessing it would be the standard F/J/Y) - but on a recent upgraded flight the bar code shows "X".

Seat # - 4 characters and the example shows a leading zero (e.g. 022F)

5 digit "check in sequence #" - example shows four digits + space (guess I was 11th that day).

1 character passenger status

or: M1xxxxxx/xxxxxx Exxxxxx SEADFWAA #### ###X022F0011 1



Now here's where it gets interesting. The next characters are the size of the variable length field and the version #.

The data in the variable length is interesting - I recognize the ticket #, my AA FF account. Let's see... the first six are lengths and codes. nothing interesting. Then Passenger description, source of check-in, source of boarding pass (W probably means Web)

(space)WW

Date of issue, oddly this is a 4 digit number with leading zero, not the 3 digit Julian day number above for the date of flight. Maybe it can be signed for a ticket issued in December for a January flight???

0###

Document type (1 char and airline designator of boarding pass issuer AA+space)

dAA(space)

Now 13 digits of "Baggage Tax License Plate Number(s) - no clue, mine are zeros but I checked no luggage

0000000000000

Then some kind of length, document says its repeated from above...

29

Now the airline numeric code and document form/serial # (3 and 10 respectively) (Interestingly the ticket # also includes 001 and so the last 3 digits of the AA ticket # are chopped off)


0010017tttttt


And there, in all it's glory is the "Selectee Indicator" and the international document verification (space for me, this was domestic)

3(space)


Now we get to other stuff I recognize - marketing carrier (AA space), FF carrier (AA space) and my FF#

AA AA A######

There's more stuff - the FF# is defined as 16 characters, so AA is using the rest of that for SOMETHING... and there's security data which looks like a standard hash (begins == and ends ==) which is probably why you can't just scan your BP, change the indicator, reprint with a phony and pass PreCheck.