Originally Posted by
gozetta
First of all, awesome detective work. Secondly, I was just able to scan mine from a free iPhone app in the appstore ("Barcode Scanners" from Manatee). Third, according to your position chart, my flight tomorrow morning has me a "0" character in Char 104, followed by a space, then "AA AA" and my FF number. Will I get the LLL??? Taking bets. It's an easy domestic non-stop.
In the part of the string that looks like this: 000000000000029XXXYYYYYYYYYY31 AA AA FFFFFFF
XXX is the airline stock code
YYYYYYYYYY is the ticket number
3 is the security flag - i've gotten 0 (no precheck) and 3 (precheck). I imagine there is also a way to encode selectee status in that field.
The second flag (1) appears to mean you're enrolled, because this stays even when you get a 0 in the first field (not selected). On BPs from before pre-check, this flag doesn't exist and the space is empty.