CHAPTER 7 CHAPTER 7 Baggage Handling
7.4 Equipment, Systems, and Technologies
This operation is known as a tail-to-tail transfer and can support a very short minimum connection time. This operation is permitted, for example, on connections between domestic flights within the United States and, in Europe, for bags that have been screened by a European airport (although some national authorities within Europe impose additional measures that mean that tail-to-tail transfers are not permitted). By their very nature, tail-to- tail transfers are not processed through an automated baggage system.
Interterminal Transfers
At multiterminal airports, transfers can occur between two different terminals. In this case, baggage typically is put into the automated baggage system of the inbound terminal, where it will be sorted to a vehicle loading dock for transport to the terminal of departure, where the bag will be processed and, ultimately, delivered to the connecting flight.
A vehicle link between terminals is a simple and effective option, but it does have the disadvantage that bags generally will have to wait for a vehicle to arrive and for loading onto the vehicle and unloading at the outbound terminal. Such an operation is not well suited for relatively short minimum connection times. To overcome this waiting, batching, and unbatching, some airports (e.g., Heathrow London, Changi Singapore) have installed automated baggage links between terminals.
swift delivery right to the aircraft, giving handlers the best chance of loading last-minute bags).
Irrespective of the arrangement of the baggage system, most bag gage systems consist of some or all of the following components.
Checkin and Bag Drop
Traditional checkin and bag-drop desks can be arranged in a number of ways:
• Linear
• Island
• Flow-through
Schematics of these three configurations are shown in Figure 7.10. Both linear and island checkin have the disadvantage that the flow of passengers leaving the desks can conflict with queues of passengers waiting to reach the desks. Flow-through arrangements, however, avoid this difficulty but are feasible only where the terminal has the space to accommodate vertical movement of bags within the checkin floor plate.
FIGURE 7.10 Checkin desk configurations.
Sorting
Once baggage has entered a system (other than the simplest), it has to be sorted.
Destinations include screening equipment, manual encoding stations, and bag storage or flight makeup locations. There are several methods of sorting bags, the choice of which is governed by a combination of factors, including
• Space
• Cost
• Required capacity
For low-capacity applications, conveyor-based merges and diverts may be chosen. For somewhat higher capacities, vertical sorting and merge units may be employed because these can switch sufficiently quickly to allow adjacent bags to be sorted to two different locations with a throughput of over 1,000 bags per hour. By their nature, vertical sorting units require greater vertical space than horizontal merges and diverts, so they may not always be a feasible solution in some restricted locations. For higher capacities still, tilt-tray sorters can be used (Figure 7.11). These operate at around 400 ft/min (2 m/s) and typically have a tray size of about 4 feet (1.2 m), giving a tray rate of 6,000 per hour.
FIGURE 7.11 Tilt-tray sorter.
In cases where loose baggage is handled, every merge, divert, incline, and sorter in- feed or output has the potential for a bag to become snagged or trapped with the risk of damage to the system and/or bag. Careful design and tuning of the system become necessary to minimize this risk; otherwise, there will be frequent system stoppages and the
associated cost of staff being needed to free jams.
An alternative approach that reduces the risk of bag jams is to use a toted system. In such a system, bags are not carried directly on conveyors but are first placed in a carrier or tray (Figure 7.12). With the provision of a secure container, each bag is less likely to catch on equipment, and by providing a standard base, the transport system can be optimized to deal with a single type of tote. Baggage tracking and storage are also made easier with totes. A bag can be identified once and then is linked in the baggage system with a given tote. The tote (rather than the bag) then is tracked using RFID tags, and this is more effective than trying repeatedly to read a bar code attached to a bag. However, tote-based systems require return routes to bring empty totes back to the baggage inputs, so they tend to require more space and, as a result, are initially more expensive to buy and install than untoted systems.
FIGURE 7.12 Tote-based system.
Hold-Baggage Screening
As screening technology develops, new and better machines become available. The control authorities build this into their regulations to ensure the best-possible chance of detection of known and potential threats. To date in Europe, three standards of x-ray screening equipment have been identified:
1. Standard 1—a single-view technology 2. Standard 2—a multiview technology
3. Standard 3—a computed tomographic technology
During 2012 in Europe, standard 1 machines will no longer be acceptable, and there
have been major programs of work at airports to replace standard 1 equipment. While the precise dates are subject to change (somewhere around 2018–2020), standard 2 machines will themselves become unacceptable and will have to be replaced by standard 3 machines. The changeover program will not be trivial because standard 3 machines weigh 6 to 8 tons and are over 17 feet (5 m) in length. An example of a computed tomographic machine is shown in Figure 7.13.
FIGURE 7.13 Hold-baggage screening equipment.
Bag Storage
Bag storage can take one of several forms. At its simplest is a manual store in which bags are grouped, by hand, by flight or departure time. This involves little more than space on the ground or racks to accommodate the bags. Automated stores vary in functionality. At one extreme, they simply automate the manual process—accumulating groups of bags in conveyor lanes by flight or build open time. Such a store does not readily lend itself to the retrieval of a single, particular bag—a whole lane of bags would have to be released to access just one specific bag.
More sophisticated stores allow random access to any particular bag. These stores usually depend on bags being carried in totes, which enable them to be transported and tracked effectively. One type of store involves setting up long conveyor loops on which the toted bags circulate slowly. As the bags pass outputs, they can be diverted so that they leave the store. Another type of store makes use of a warehouse crane and racking approach (Figure 7.14). Toted bags entering the store are taken by crane and placed in a slot in a lane of racking. This, too, allows single bags to be retrieved and thereby offers the
most flexible of storage systems.
FIGURE 7.14 Crane-served bag store.
Flight Build
The type and configuration of manual makeup devices are varied, including
• Chutes
• Carousels
• Laterals
Each offers a combination of advantages and drawbacks. Chutes can be arranged space efficiently, thereby ensuring a one-to-one mapping between chute and ULD and/or trailer.
However, they suffer from poorer handling ergonomics than laterals. Carousels offer a
flexible means of distributing bags to several makeup positions, but there can be concerns over the ergonomics of picking bags from a moving device. Laterals (Figure 7.15) can be set at an optimal height for operators and are compatible with modern manual handling aids.
FIGURE 7.15 Build lateral.
New ways of handling flight build are being implemented, and these require different makeup devices. Of particular note are fully automated, robot-based build cells and semiautomated batch build devices.
A build cell employs a robotic arm fitted with a specialized handling tool to receive a bag from the baggage-handling system and, using a machine vision system, then will place the bag into a trailer or ULD. The work rate achieved by such systems is typically three to four bags per minute—not necessarily faster than a human operator, but it is sustainable indefinitely and relieves handlers of the physical load. A build cell cannot operate unsupervised. In the course of filling a ULD with a capacity of, say, 40 bags, the supervisor may have to intervene a couple of times to reseat a bag that has slipped or fallen. The robotic system can fill ULDs to around 80 percent capacity. A baggage handler usually can fill the remaining space by hand. Practical build-cell designs recognize this and integrate both the automated element and the manual topping-up element, combining the cell supervisor’s role with that of the baggage handler.
A semiautomated batch build arrangement employs a steerable, extendable conveyor controlled by an operator. This device is used to deliver bags into a trailer or ULD. The
speed of placement can be much greater than that of a robot-based system, given that bags are delivered to the device sufficiently quickly—10 bags per minute can be achieved.
Increasing the build rate allows build open times to be reduced. A conventionally built long- haul flight might be open for three hours, during which time 12 ULDs might be filled.
Assuming about 40 bags per ULD, the average work rate is two to three bags per minute.
The batch build arrangement, in theory, could be completed in less than an hour. Practical considerations mean that such a reduction in build time actually will not be possible, but halving the build time is conceivable given appropriate controls and logistic support (e.g., delivery and removal of ULDs from the makeup area). This can translate into reductions in both staffing and infrastructure, although this will depend on the specific pattern of flights and staff shifts.
To be used efficiently, both robot-based and semiautomated approaches require the baggage-handling system to be able to store, batch, and deliver bags for a single segregation (i.e., ULD or trailer). Figure 7.16 shows an example of a batch and compressed build process. The cost-benefit assessment of these concepts greatly depends on the cost of labor and the impact of health and safety regulations. For this reason, early adopters have been European airports.
FIGURE 7.16 Batch and compressed build process.
ULDs that are filled with bags in a baggage makeup facility will be transported to the departure stand on dollies (Figure 7.17).
FIGURE 7.17 Tug and dolly train.
Reclaim
The most common baggage reclaim device is a carousel, of which there are several variants. The two principal choices are
• Flatbed or inclined
• Direct or indirect infeed(s)
Flatbed carousels (Figure 7.18a) are preferred, if space permits, because bags are more easily picked off by passengers. An inclined carousel (Figure 7.18b) accommodates more bags per unit length—0.75 bag/foot (2.5 bags/meter) rather than 0.5 bag/foot (1.5 bags/ meter) for a flatbed—but at the expense of bags being piled one upon another. This can make it difficult for passengers to retrieve their bags, particularly if theirs is trapped by a heavy bag that has fallen on top of it.
FIGURE 7.18 (a) Flatbed reclaim. (b) Inclined reclaim.
Bags can be loaded directly onto the device, or they can be fed indirectly via one or
higher linear density of bags can be achieved than is possible with indirect feeds. However, by using indirect feeds, the adjacency between the reclaim carousel and the vehicle docks (where the bags are actually unloaded) can be relaxed. This may be desirable or even necessary to fit with a terminal building design.