A baggage handling system (BHS) is a type of conveyor system installed in airports that transports checked luggage from ticket counters to areas where the bags can be loaded onto airplanes. A BHS also transports checked baggage coming from airplanes to baggage claims or to an area where the bag can be loaded onto another airplane.

Although the primary function of a BHS is the transportation of bags, a typical BHS will serve other functions involved in making sure that a bag gets to the correct location in the airport. Sortation is the process of identifying a bag and the information associated with it, to decide where the bag should be directed within the system.

In addition to sortation, a BHS may also perform the following functions:

Detection of bag jams
Volume regulation (to ensure that input points are controlled to avoid overloading system)
Load balancing (to evenly distribute bag volume between conveyor sub-systems)
Bag counting
Bag tracking
Redirection of bags via pusher or diverter
Automatic Tag Reader (ATR) (Reads the tags on the luggage provided by the airlines)

There is an entire process that the BHS controls. From the moment the bag is set on the inbound conveyor, to the gathering conveyor, through sorting until it arrives at the designated aircraft and onto the baggage carousel after the flight, the BHS has control over the bag

Many baggage handling systems offer software to better manage the system. There has also been a breakthrough with “mobile” BHS software where managers of the system can check and correct problems from their mobile phone.

Post September 11, 2001, majority of airports around the world began to implement baggage screening directly into BHS. These systems are referred to as “Checked Baggage Inspection System” by the Transportation Security Administration (TSA) in the USA, where baggage are fed directly into Explosive Detection System (EDS) machines. A CBIS can sort baggage based on each bag’s security status assigned by an EDS machine or by a security screening operator. CBIS design standards and guidelines are issued by the TSA once every year since 2008. All CBIS built in the USA must comply with the standard set forth by the TSA. The latest standards can be downloaded from the TSA’s website here.

The first automated baggage handling system was invented by BNP Associates in 1971, and this technology is in use in almost every major airport worldwide today.

Development of the baggage handling system
With the rise of aviation more and more people used aircraft as a means of transport, the aircraft were getting bigger and the airports more and more complex. Because there the passengers were no longer allows their luggage themselves on the run-up to receive or deliver, and that the introduction of the jetway no longer entered the run-up, a system had to be invented, the luggage first from check-in to the aircraft and after landing, from the aircraft to a separate area for the return of baggage transported by the passengers.

The first baggage handling systems consisted mostly of simple, straight conveyor belts, whose technology was taken from the open pit. Over time, facilities became more complex and new facilities – such as round conveyor belts (sorting lanes, sorting facilities and parking facilities) – had to be introduced to cope with the ever-increasing volume of luggage.

Operating principle
Passengers hand over their luggage at a counter – the so-called check-in counter. A conveyor belt then transports it to a location where it is loaded on to wagons and finally by airport personnel specializing in fast loading and unloading.

Conversely, when an aircraft arrives, the luggage is unloaded from the aircraft and transported to the wagon. The cars are driven to a collection point not visible to the passenger. This is often under a roof next to the terminal building. At this point, the luggage is placed on a conveyor belt, which then transports the luggage inside the building. There, the luggage – on the so-called baggage delivery belt – can be received by the passengers.

Conveyor technology
There are two basic principles of materials handling:

simple, “loose” transport of luggage
Container conveyor technology, in which luggage is transported in containers
Systems with containers
This system can be found, for example, at Frankfurt Airport or in Terminal 2 at Munich Airport. Here are the pieces of luggage in the so-called “wedding” with a container “married”. Then, the containers will then head for their destination, with the identification of the baggage functioning via reflective marks or bar codes attached to the container, and thus much easier to read than a system in which the item of baggage may conceal the luggage tag with the destination information.

Here one must differentiate between active and passive conveyor units: Active conveyor units have a motor and drive their route automatically, whereby the conveyor line itself is quite cheap and straightforward (easy to maintain). Passive conveyor units are driven by belts and / or rollers, thus requiring a more complex route, but have much cheaper container, since these are usually simple plastic tubs.

The great advantage of the container conveyor system is that an extra sorting system is not necessary, as this takes place decentrally quasi on the way (comparable to a highway trip from Frankfurt to Munich, where the corresponding branches are taken). Furthermore, higher speeds are possible than with tape systems and there are fewer “baggage losses” due to falling off the belt or getting stuck. More fragile pieces of luggage also suffer less damage.

The disadvantages would be cost and maintenance, as well as the problem of empty containers, which in some way have to return to check-in. At Munich Airport, this was efficiently solved by taking the empty containers with the luggage of the arriving passengers on the way back.

This system is only worthwhile at large airports.

Systems without containers
This system can be found at most smaller airports as it is easy to maintain and cheap. Suitcases are easily transported by conveyor belts, chutes and sometimes by rollers.

To identify the items of baggage, the barcode on the labels affixed to the items of luggage must be read again and again at scanner gates. This is often associated with problems because the barcode must be within the field of view of the scanners. There are different approaches to sorting, such as:

so-called pusher (mostly used in the US)
cross-belt sorter
Tilting tray sorters, which can be found, for example, in Terminal 1 of Munich Airport
In order to be able to sort the pieces of luggage, a certain minimum distance between them is often necessary, so that they are separated over short, differently fast conveyor belts. This is also necessary to speed up pieces of luggage, for example, for a fast Kippschalenster cycle.

Advantages of this are mainly cost-effective, whereas the disadvantages are the maximum throughput (2 to 3 m / s compared to 12 to 14 m / s in container systems), as well as the high amount of luggage lost in the system (falling off the belt, hang on corners, tilt in front of X-ray device or similar).

Present
Mile-long conveyor belt systems are installed at major airports, such as Frankfurt, and the items of baggage are transported individually to trays for more efficient use of equipment via barcodes, sorting, faster transportation, diverting and storing luggage.

At the airport in Kuala Lumpur, the system, now called the Baggage Handling System, consists of 33 km of belts, some of which run through a kilometer-long tunnel between the buildings. The trays with the pieces of luggage are accelerated at some plants up to 40 km / h, in order to be able to reload a piece of luggage from one airplane to the next as fast as possible.

Efficiency criteria
The IATA establishes criteria for an efficient system, allowing better coordination between airports. These criteria include the following aspects:

Fast, simple movements and require the least number of handling interventions.
System capacity proportional to the number of parking spaces, volume and type of traffic.
Minimum number of turns and level changes.
Maximum 18º slopes (for the prevention of damages in luggage).
The movement of baggage should not interfere with that of passengers, crews or cargo.
Provide necessary elements for transporting luggage in connections.
The circulation on platform should not be hindered by any type of control.
If it does not yet exist, provide spaces for 100% inspection.
Foresee redundancies so that the system continues to work if a part fails.
Parts of the system
An SATE is composed of the following parts or systems and, in turn, these are divided into other subsystems.

Origin / connections output system
Input subsystem:
Billing (heavy, labeled, CUTE).
Connection input (label reader or manual labeling).

Subsystem classification:
Specific to automated systems.
Routes based on routes, breakdowns…
Normally: interleaved readers, deviators, tilt trays, pushers, recirculation circuits…
Transport subsystem: of counters, collectors, transport, classification circuits, court feeders, interconnection, warehouse, transfer, special baggage, etc.
Storage subsystem: early luggage.
Subsystem of exit: patio of cheeks, cheeks, pallets…
Arrival system of final destination
Input subsystem: optional if direct carriage is used in carrillos.
Classification subsystem: optional if direct carriage is used in carrillos.
Transport subsystem: fast tapes, carriage trains.
Output subsystem: racetracks for baggage collection plus food (optional).

Management and control system
Central management, local control, level of local action.
It houses supervisory and fire subsystems.
Operation mode
Each suitcase is identified by its barcode and commonly goes on a tray that is identified by an RFID system. In this case, the license plate number and the barcode of the suitcase are linked and then by sensors the tray follows the predefined route that takes you to your destination. The use of trays with RFID supposes, according to IATA, an increase of efficiency of 80-90% to 95%.

Due to the automation it is practically impossible the loss of a luggage. It is even capable of taking suitcases of the route if the flight is going to be delayed and to introduce them at the time that is necessary.

Components of a baggage handling system
A baggage system consists of the following parts:

check-in counters
conveyor belts
sorting machines
luggage carousel
rail systems with carts
barcode scanners
RFID scanners
screening machines (EDS explosive detection system)
computer systems
specialized software

Applicable technologies
Conventional technologies
The characteristics of conventional technologies are:

They are sufficiently tested in service and offer available data on: capacity, costs, reliability…
A wide range of suppliers, resulting in improvements in price due to high competitiveness.
The main parts that are found are:

Conventional conveyor belts.
Low speed: With speed less than 1.5 m / s.
High speed: With speed from 1.5 m / s up to 2.5 m / s.
Identification and control system.
Arcos automatic laser reading of labels.
Follow-up photoelectric cells.
Manual scanners and / or RFIDS.
Systems for cheek formation / luggage collection:
Race tracks, accumulation springs, hoppers and ramps.
Security systems:
Inspection machines levels 1, 2 and 3.
Vapor inspection systems.
Baggage / passenger reconciliation system.
High speed technologies
The characteristics are the following:

They are able to cover medium / long distances.
They develop high speeds (up to 5-10m / s).
Complexity of the control system.
Individualized maintenance to DCVs.
There is a smaller number of suppliers, so there is less competitiveness.
The vehicles characteristic of this type of technology are:

DCVs type 1 or 2 (Vehicles with coded destination, can choose road)
Tray systems on belt conveyors.
Self-propelled DCVs.

Logical process
The baggage sorting has as main moments the picking up of the baggage from the hands of the passenger and its loading on the plane, and vice versa its unloading from the aircraft and returning it to the passenger, to the arrival station.

A particular case occurs in passenger transit stops, where the baggage must be unloaded from one plane and loaded onto another.

In these cases the transfer of baggage can take place directly from aircraft to aircraft, through tractors and trolleys that circulate on the square, or by reinserting the luggage in the automated sorting system, which will provide the correct routing to the departing aircraft.

Architecture
We do not consider baggage sorting here without the help of technological infrastructure.

A baggage sorting traditionally operates through conveyor belts, but there are also systems based on trolleys, even mono-baggage, that move along tracks or along optical or magnetic tracks.

The tape originates from the check-in counter, where the passenger registers the baggage in his own name; an identification tag (tag) is affixed to the baggage which will allow the system to route it appropriately towards the loading dock.

Once started, the baggage is transported to a loading dock, equivalent to a dead track; from this pier it is picked up and loaded on trolleys on wheels (the so-called “loose” luggage), which are then towed to the aircraft, where they are loaded in the hold manually or through small conveyor belts. As an alternative, for the prepared planes (they must be large enough) the luggage is loaded in special containers called ULD (Unit Load Device), normally in aluminum, which once filled are loaded in a single solution on the plane through special lifts.

The route of the luggage belts inside the BHS can also be very complex, and provide for changes in the direction of baggage: these changes are checked by reading the baggage tag and identifying the associated loading dock.

There are also waiting paths (recirculation belts), in which the luggage is stored while waiting for the conditions for the route to the loading dock to materialize – this is the case, for example, of passengers on waiting lists.

Upon arrival, the baggage is unloaded from the plane, and then taken and loaded onto the conveyor belts at special loading docks. The baggage is then appropriately routed to the redelivery belt for passengers; the appropriate route is chosen thanks to the reading of the label affixed to the luggage.

The baggage that is not automatically recognized passes to a manual recognition, and if it is no longer possible to identify the baggage, it is taken to the lost baggage office (Lost & Found).

IATA Messaging
The routing of baggage is done thanks to the information sent by the airlines at the time of acceptance of the baggage (check-in) and received by the BHS control system. These messages are defined and standardized by IATA, and can be:

BSM (Baggage Source Message): has the purpose to indicate to BHS which flight is destined the baggage with a given label (this message also provides further information, such as the fact that the baggage is or not on the waiting list, if required X-ray control (X-ray inspection), etc.
BTM (Baggage Transfer Message): it is a message similar to the previous one, but is intended to allow the management of baggage in transit, that is, those arriving that must be downloaded and transferred on a connecting flight.
Evaluation parameters of a BHS
The efficiency of a BHS is measured according to two main parameters, which are:

the number of checked baggage per hour
the percentage of error in baggage routing
The first parameter can be improved by increasing the speed of the tapes, while the second by using more sophisticated systems for reading the baggage tags (Bag Tag). The use of RFID tags prevents many problems related to the occasional illegibility of labels.

The time required to transfer a baggage (and its owner, of course) from one flight to another helps to define the so-called connecting time (MCT – Minimum Connection Time) of an airport: the smaller the airport is, the more efficient in handling passengers and baggage, allowing ticket agencies to issue tickets for faster connections.

The journey of a suitcase
When a passenger checks in his or her luggage, a luggage tag is hung on the suitcase. On this label, in addition to the flight number, flight date and airport of destination, there is also a barcode and a number, the license plate code (LPC). There is also an RFID chip in the labels nowadays.

The suitcase then goes on the conveyor belt between the check-in desks and disappears from the view of the passenger. Transfer cases are also loaded on unloading quays.

At that moment the suitcase enters the baggage system. First of all, the suitcase is weighed and measured, too large, too high or too long objects are poured and are brought manually to their sorting belt. After this the label of the suitcase is scanned and the computer system searches for the associated flight and on which sorting belt it is planned. This determines the route of the suitcase through the system.

After this, the suitcase passes through at least one screening machine, which checks whether there are no explosives or other hazardous materials in the suitcase.

If the suitcase is safe, it is checked whether the sorting belt is already open for the flight. If the passenger has checked in very early, it may be that the flight is not yet open. Then the suitcase can temporarily be stored in a buffer. When the flight opens, the suitcases for that flight will spread out of the buffer and continue their journey.

If the flight is open, the suitcase will go to the sorting belt, there can be a final check, the make-up. In this check it is checked whether the passenger is already at the gate. If not, the case will not (yet) be loaded onto the plane. The suitcases that have been approved are loaded manually or with a robot in containers or on luggage trolleys.

These containers or baggage carts are then brought to the plane. There the journey of the suitcase ends through the baggage system.

Source from Wikipedia