Friday, August 07, 2009

What's on a baggage tag?

Very recently Alitalia managed to lose all my luggage twice in one week. Of course, when I say lose I simply mean delay. They did in the end (after days of delay) get it all back to me.

But it got me wondering about how baggage is tracked. I mentioned this in the office and a colleague said that he had heard from a guy working on RFID tagging of airline baggage that there was a little secret: the current bag numbers are too short for the volume of bags being handled.

Naturally, I decided to try to find out whether this was true.

Firstly, from a technical standpoint the numbers on baggage tags (called a 'license plate' in industry parlance) consist of 10 digit base-10 numbers. There are three separate fields: a three digit airline identifier (which is the numeric version of something like BA or AA and does not include flight number), a one digit field used by the airline and a six digit serial number. All of this is specified in IATA Resolution 740.

Here's an example given by the airline Malev

Item number 1 there is the baggage tag number (MA759235). It shows the airline identifier as letters (in this case MA instead of the three digit IATA code which would be 182). That is followed by the six digit bag serial number.

At the bottom under the bar code is that actual 10 digit IATA number which starts with 0 (that's the single digit the airline gets to use for its own purpose), then there's the airline code (182) and then the serial number: 0182759235.

The six digit number identifies the bag. With six digits the airline can have up to 1 million unique bags in their systems at any one time. So I instantly wondered how long it would be before an airline would reuse a bag number.

Wikipedia tells me that the largest number of passengers carried in 2007 was by Southwest Airlines with over 100m passengers. Just behind was American Airlines with 98m.

Making some wild assumptions: each passenger checks a single bag and the passengers are evenly distributed across the year that says that Southwest Airlines and American Airlines handle 1m bags every 4 days.

So then I wondered. What happens if my bag gets lost and it stays lost for too long. Does my number get reused? Does this have an effect on me getting it back?

For that I decided to go the traditional route and talk to the people who know: IATA, BATA and the airlines. I prepared an email with a sequence of questions around the story, introduced myself and this blog and sent off messages. I also considered buying the complete IATA regulations, but they are rather expensive.

The IATA and American Airlines simply did not reply. When I tried to register for access to the IATA web site my access was denied. British Airways kindly replied and told me that they couldn't comment on an 'industry-wide issue'. The British Air Transport Association replied and said they were too small to answer my questions which really needed to go to IATA.

The Civil Aviation Authority replied and told me that I was asking about a 'security issue' (oddly) and that I needed to ask the UK Department of Transport. They didn't reply.

At this point I realized why people get paid at newspapers: it takes time and money to investigate things. So, to save my time and money I mentioned this to someone I know who works at The Times in the UK. She took the bull by the horns and got the IATA on the phone.

To cut a long story short the IATA claims that this isn't a problem for two reasons: that single digit field can be used to turn 1m bags into 10m (this is up to the airlines to implement and it wasn't clear who is implementing that) and that reuse isn't a problem because if it does occur the system records the information about both people and flights using the same bag number (it was unclear from IATA exactly how long these records are held onto: they appeared to say six days).

But I'm not really satisfied. It would be nice to really know. Does number reuse occur in practice? And does it have an effect on the handling of delayed baggage?

Anyone out there work for an airline and want to give me the inside scoop?


Tom Coady said...

It doesn't matter if the six digit bag serial number gets reused every day as there is also a date on each tag.

John Graham-Cumming said...

@tom Problem is the date isn't in the 10 digit field that's in the bar code.

Paul Mison said...

"The Civil Aviation Authority replied and told me that I was asking about a 'security issue' (oddly)"

Actually, that's not odd at all: the barcodes are a security measure, and they're not for your benefit, they're for the airlines. The idea is to make sure that both the passenger and their bag make it onto the plane. If the bag goes into the hold and the passenger doesn't clear the gate, then they can identify the bag and pull it out.

The reasoning for this is to avoid a Lockerbie-style attack, or at least make sure that the perpetrator is suicidal before doing it.

This is all explained in
The Secret Life Of The Airport, about 30-40 minutes into episode 3, if you're interested.

John said...

The fact is the U.S. Airlines have little to no interest in what passengers feel about baggage losses. As one airline executive (SVP level) told me, "customers only care about airfare pricing and will cut us for $5. So, we do not see baggage as a problem." The attitude of the major airlines is focused on survival at any cost to a passenger. As another has said, "the only time we know the location of a passenger's bag is when they hand it to us at the check-in counter and when they pick it up at the carousel."

Phineas said...

Terminal 5 handles 70,000 bags a day

This is most but not all of BA's baggage.

martijn said...

I was surprised to discover that the code doesn't refer to the airport the bag needs to go to. It would make it very easy for airports to sort incoming baggage into 'stays here' and 'needs to travel further' (most baggage, I think, gets lost during transfers). But then I thought that that would probably make abuse very easy; in case of doubt you will want a human to look at the baggage. Still, using five extra digits will make it much harder to for abusers to use a random code without being detected.

Don't barcodes have a checksum as well? Ones used on products do, although I can imagine the checksum here is only in the bars, not in the numbers.

(I'm not a frequent flyer, but my bags got lost once. When I flew with Alitalia.)

Ben Meadowcroft said...

At a previous employer I used to work on UltraTrak yes numbers get reused but it isn't a problem as it isn't intended to be a globally unique identifier for the bag, just unique enough for the loading safely onto the plane. To locate a lost bag you also have passenger and flight and date information which is recorded in the tracking databases and which is use to search for the last seen location and time of a bag in any decent baggage handling system. Airlines typically structure their bag numbers so that there aren't clashes within an airport.

@martijn the physical tag typically usually includes the destination code already. There's no need to encode it in the tag as it can be looked up from the tag in the tracking database. If there ahppens to be a duplicate bag tag in the system the baggage handler would be prompted for the flight or passenger which they would then select based on the information on the physical tag. This is a fairly rare occurrence so doesn't yet justify the cost that would be associated with changing the existing legacy systems.

Ed said...

Tracking or tracing a bag requires a date, flight number, origin, destination, passenger last name, as well as tag number. Tracing systems will actually trace with less than the full list of requirements above - but you can see that the sole requirement is not just the tag number.
RFID is a great concept, and hopefully it will come, if it proves sufficiently reliable and economical.

Davetf said...

As a passenegr who has just "lost " luggage during the recent weather chaos in London, can anyone explain how to locate the lost luggage? After flying from Glasgow to Gatwick there was a very short change before departing to Atlanta, followed by another quick change in Atlanta. On arrival at the final detination the luggage was reported as missing, but after 4 days neither the airline (Delta)or the baggage handlers (Servisair) can tell me where it is. It could still be at Gatwick having been too late to be loaded onto the Atlanta flight, or it could still be in Atlanta for the same reason. - or it could never have left Glasgow. Can't the security system locate individula peices of baggage?