My GF and I flew a 3 leg trip 2 weekends ago. Only when we were on our second flight did we realise that we had used the BP for her 3rd leg on the 2nd. If it mattered, NW's computer didn't catch it as the BPs were scanned (seats were the same for both 2nd and 3rd legs so that might have had something to do with it). After we got off at the 2nd stop, I asked a gate agent to reconfirm she had flown the 2nd leg, and called a telephone agent when we arrived at the final destination.

Looking at the BPs, the bar coding seems to be identical expect for the right 3rd.

I've been on two flights in the past two years (one on NW on on Frontier) where a psgr had boarded a plane to the wrong destination. On NW, at least they caught it before pushback; on Frontier we had already taxied for a while before we ended up going back to the gate to let a woman off so she could go to some city other than ABQ. Given that people get on flights they aren't even supposed to be on, it isn't terribly surprising that you were able to get on using an out-of-sequence BP.

That is strange, I was flying PVG to NRT to DTW,when I got to NRT the board said DTW so as the GA put my pass into the computer slot it was rejected .
NWA has two flights to DTW and mine left an hour latter.Maybe if same flight# the computer won't catch it

Given yours and clarence5ybr's rely I think the computer might only look at seat assignments and unless there's 2 or more pax assigned to the same seat, it won't flag anything. Since she had the same seat for the 2nd and 3rd legs (flight numbers were different), the computer didn't notice anything out of the ordinary. When we got to MEM, I asked an agent who said she was shown on the system as having flown the DTW-MEM leg.

If the system did look at name, I'd imagine any pax who shouldn't be onboard would be caught at boarding.

You're right. The computer matches the bar code with the seat assignment only. I know this b/c when I was the first person to board an Airlink flight out of MEM the GA setup the boarding computer with the wrong flight number and when she scanned my boarding pass it came up G2B for a female passenger and surprisingly the GA figured out that it was not me.

Hair not long enough

scary loopholes in system? how does this happen??
does that little scanner do something or just beep?

once on an early morning flight (maybe we were all half-asleep) and we were taxi-ing out getting the usual flight announcements. all of the sudden this man w/ a small baby come running up the aisle (everyone suddenly wide awake at this point) and the plane comes to a screeching halt. we turned around and went back to the terminal b/c he was on the wrong flight, wrong destination all together.

The beep lets the GA know that the pax is GTB (good to board). At that time, it displays the passenger's name on the computer screen along with some other info. The GA is supposed to match the pax name on the boarding pass with the name that appears on the screen when the computer beeps. So I think you can guess how often these 2 names get confirmed.

Sounds like the barcode is the PNR (Passenger Name Record*) number and seat assignment. In this case, the PNR # and seat assignments on the 2nd & 3rd legs were the same, so the boarding passes could be used out of sequence. Here would be the logic:
1) prior to boarding, the gate reader was intitalized as working flight "123"
2) passenger Mr Terenz presents his boarding pass while boarding
3) the gate reader scans the barcode as PNR #ABC789 and seat #1A
4) gate reader transmits this to the reservations computer
5) res computer pulls record #ABC789
6) res computer sees this record has a confirmed reservation for flt 123 today
7) res computer sees the segment on flt 123 is "checked in", seat 1A
8) res computer info matches that received from gate reader
9) res computer sends back "ok" and name of "terenz" to the gate reader
10)gate reader "beeps" after getting the "ok" & displays the name sent to it
11)gate agent hears "ok" beep, so double checks the name
12)gate agent sees name "terenz" on gate reader and boarding pass
13)gate agent says "Welcome Mr terenz" (or grunts; based on mood)
Out of sequence is irrelevant cuz both barcodes say "PNR #ABC123, seat 1A"

Did I mention I used to be a Gate Agent (for AA .. ughh)
They can't double check the name for all 150+ passengers boarding within the 30 minutes boarding time (assuming boarding started on time) and do their 100 thousand other duties and get the flight out on time. Some name mis-matches will slip thru and board the wrong plane. That's why it's the Flight Attendants job to announce a couple of times during boarding that this is "flight 123 to Timbuktu". The passenger who flies a flight to the wrong destination shares 50/50 of the blame with the hurried Gate Agent.

Did I mention I'm now a Computer Programmer (not AA, tho I started programming there).
My alledged scenario could very well be true. The passenger name could also be encoded on the barcode so that all verification lies within the reservation computer. But how many parameters due you want to pass on that bar code?? Keep in mind that every scan from the gate reader computer has to transmit all barcode parameters to the main (reservations) computer. Sometimes (as in gates shared between multiple airlines) that transmission is done via a radio link. You need to keep the amount of data transmitted back and forth to a minimum; this isn't a batch job being run in the middle of the night when the computers aren't busy with more important jobs; this is 150+ passengers standing in line and we must have all of them processed in 30 minutes. Keep data transfers to a minimum.

Steve


* PNR - commonly called a "confirmation number" but it doesn't confirm anything, it's just a record locator in the computer to pull a given reservation, ticketed or not. It will contain the currently booked flights w/details (seats, FF # etc) as well as a history of all flights previously booked/cancelled under this reservation.

But then why when my boarding pass was scanned after the computer was initialized on the wrong flight number did it bring up another passenger in the same seat? It was a Mesaba flight out MEM, if that matters.