The CUSS Handbook  /  Common-use self bag drop

Common-use self bag drop

Check-in was the easy half. Baggage acceptance touches the physical world, a regulated security regime and a downstream sortation system that has to be told, correctly, where every bag is going — and it has to do all that on equipment shared between airlines.

What self bag drop is

Self bag drop lets a passenger present a checked bag without an agent performing the acceptance. In the common-use case, the unit belongs to the airport or a service provider and is used in turn by many carriers, exactly as with a kiosk. The passenger identifies themselves and their booking, the bag is weighed and measured, a tag is applied, the bag is accepted onto the belt, and a baggage message goes downstream so the sortation system knows what it has.

The standards support this from more than one direction. The CUSS standard covers self-service devices including self-service baggage drop-off; IATA notes that recent CUPPS features include baggage drop device integration; and Common Use Web Services, Recommended Practice 1741, standardises the data exchange supporting common-use self bag drop through web-services technology.

One step or two

Deployments generally follow one of two patterns, and the choice has large consequences for hall layout.

Two-step. The passenger obtains a bag tag at one device — a check-in kiosk, typically — applies it themselves, then carries the tagged bag to a separate drop unit that reads the tag and accepts the bag. Throughput at the drop unit is high because the slow, error-prone part (a passenger threading a tag onto a handle) has been moved off it. The cost is that passengers must be guided through two locations and some will arrive at the drop with the tag applied wrongly.

One-step. A single unit does identification, tagging and acceptance. It is simpler to explain and simpler to signpost, and it suits halls where there is no sensible place to put a separate tagging position. It is slower per passenger, and each unit is more complex and more expensive, since every one needs a tag printer as well as a full acceptance mechanism.

Neither is correct in general. The determining factors are hall geometry, the peak-hour profile, the proportion of passengers with bags, and how much of the traffic is transfer rather than originating.

Why acceptance is harder than check-in

Several things make bag drop materially harder to deliver on shared infrastructure.

• It has physical failure modes. An oversized bag, a bag with loose straps, a bag placed across two belts, a bag that will not clear a profile scanner. A check-in transaction that goes wrong wastes a minute; an acceptance that goes wrong blocks a lane.
• It is a security process. Acceptance is the point at which a bag enters the secure baggage system, and the questions of who the bag belongs to and whether that person is travelling are regulated ones. Requirements vary by jurisdiction, and the standard cannot flatten that.
• It must be reconciled. A checked bag has to be associable with a boarded passenger. That obligation persists regardless of who accepted the bag.
• It generates downstream messages. Baggage handling depends on standardised messaging and on the IATA licence plate concept for identifying a bag through sortation. IATA maintains these under its baggage standards programme. A common-use acceptance unit must emit correct messages for whichever carrier it is currently acting for — and the carriers' downstream systems differ.
• Its device set is heavy. Scales, conveyors, profile scanners, tag printers and applicators. Every one is an availability risk and a maintenance obligation, and every one has to be represented to an application through the platform's device abstraction.

Accessibility applies here too

A self bag drop unit in the United States can fall within the definition of an automated airport kiosk depending on its function and location, and the accessibility rule attaches to function, not to what the machine is called. Where kiosks in a location perform more than one function, the accessible units must provide all the same functions as the inaccessible ones — so an estate that makes check-in accessible but leaves bag drop unreachable has not solved the problem. This is set out on the kiosk accessibility page.

The physical dimension is real and is easy to overlook: reach ranges, the height of a belt, the force needed to move a bag into position, and whether a passenger using a wheelchair can complete acceptance unaided.

What to check before committing

1. Which model — one-step or two-step — the hall geometry and peak profile actually support, rather than which one the reference site used.
2. Whether the tag reading and messaging behaviour has been proven with every carrier expected to use the units, not with the launch carrier alone.
3. What happens when a bag is rejected: where the passenger goes, and whether that path is staffed.
4. How availability is measured and who is accountable when a lane is down. This belongs in the service level agreement.
5. Whether the accessible unit provision covers the acceptance function and not only check-in.

Research from the Airport Cooperative Research Program is unusually good on the operational planning side of this — see sources.