CHAPTER 7 CHAPTER 7 Baggage Handling
7.3 Baggage-Handling Processes Overview
A typical set of baggage processes is shown in Figure 7.2. While all commercial airports will have checkin, reclaim, and flight build facilities (also called makeup), only hub airports will have any significant transfer-baggage facilities. Hub airports with multiple terminals also may have a significant interterminal transfer process connecting passengers and their bags arriving at one terminal with their departure flights in a different terminal.
FIGURE 7.2 Typical baggage processes.
Bags entering the system via a bag drop generally will be screened in the terminal of departure. Once in the baggage system, optionally, they may be stored and then delivered to a flight build output. From there they are taken to the departing aircraft and loaded.
Terminating bags arriving at a terminal will be delivered to reclaim for collection by passengers. In some circumstances and jurisdictions, terminating bags are screened for illicit items.
Transfer bags arriving at a terminal will be input into the baggage system and routed to the terminal of departure. Once there, the process follows that for locally checked-in baggage. The major elements in this process are described in turn in the following sections.
Bag Drop
Off-airport checkin can be offered in a number of ways including in-town airline offices, checkin counters at downtown train stations, and services supporting checkin and bag drop at hotels. For example, in Hong Kong, most airlines have checkin counters at both Hong Kong and Kowloon Stations. Airport Express passengers can check in and leave baggage at these facilities so that they are free to visit the city for the rest of day before leaving for the airport without having to carry their baggage around with them.
Car-park and curbside checkins are convenient ways to check in for a flight and to drop bags without having to take them through a crowded airport building. They typically operate as follows:
• Pull up to a booth in a car park or the curb adjacent to the departure terminal, and present a photo ID along with a confirmation number, destination, flight number, or e-ticket number to an agent.
• Hand checked bags to the agent, collect the baggage receipt and boarding pass, and proceed straight to security.
In 2012, American Airlines offered curbside checkin at 66 U.S. airports, whereas Delta offered the service at approximately 100 U.S. airports.
Terminal checkin is ubiquitous. This, historically, has been carried out at staffed combined checkin and bag-drop desks. The passenger presents travel and identification documents to the checkin agent, who assigns a seat number. If the passenger has baggage to check in too, then the agent typically will print and attach bar-coded tags to each bag and issue baggage receipts to the passenger. The agent then will dispatch the bags into the baggage system.
Since more and more checkin functions can be performed online (e.g., seat selection, boarding-card printing), the traditional checkin arrangement at airports is becoming increasingly deconstructed to allow passengers to make use of the functions they require while bypassing others. Figure 7.3 shows how passengers can access the required combination of functions for their needs.
FIGURE 7.3 Flexible checkin options.
Typically, there will be three waves, each wave being encountered by passengers as they makes their way through the departure concourse. The first wave is provided by self- service kiosks that support checkin, seat selection, and boarding-card printing (Figure 7.4).
Optionally, these kiosks may support bag tag printing and attachment. The kiosks are less space-consuming, can be more flexibly located, and are cheaper than conventional desks.
Because these kiosks allow for more units and keep transaction times down, passengers benefit from fewer queues than otherwise would be the case with conventional checkin.
And because one member of staff can host and support a group of kiosks, operational costs for airlines and handlers are reduced for a given level of service.
FIGURE 7.4 Self-service kiosk.
The second wave is a bag drop where passengers can deposit hold baggage. Often these bag drops are physically indistinguishable from a conventional checkin desk and are staffed in the same way—it is simply that they are used purely for baggage acceptance. A typical example of such facility is shown in Figure 7.5.
FIGURE 7.5 Staffed bag drop.
There is growing interest in self-service bag drops, where passengers can deposit baggage without the need for a member of staff. Qantas is an early adopter of this approach for domestic traffic. In this arrangement, bag tags are printed and attached at a checkin kiosk [or permanent radiofrequency ID (RFID) tags are used for frequent flyers] so that when the passenger reaches the bag drop, there is little more to do than put the bag onto the receiving conveyor (Figure 7.6). The average process time is in the range of 20 to 30 seconds per bag. This short process time (compared with 1 to 2 minutes or more for conventional checkin and bag drop), coupled with multiple bag drops, means that there are rarely queues of passengers waiting to deposit bags.
FIGURE 7.6 Self-service bag drop.
The third wave has full-service desks. Here, any of the functions performed in waves one and two also can be performed, and they can deal with additional functions such as taking payment for excess baggage or rebooking.
Passengers still may reach the departure gate with baggage that an airline may not choose or be able to carry in the cabin. Therefore, there usually will be the opportunity, at the gate, for an agent to tag a bag and then have the bag loaded into the aircraft hold.
Since this is a time-consuming activity that would slow up aircraft boarding if left to the last moment, airports and airlines often will employ a series of measures to minimize the number of last-minute gate bags. This usually will involve one or more of the following:
• Agents inspecting all baggage at checkin for size to capture all non-cabin- compatible items.
• Limits placed on the size of baggage at passenger screening, necessitating the prior checkin of items that cannot be carried in the cabin.
• Agents spotting passengers waiting in and around gate areas with unsuitable baggage so that the items can be tagged and loaded before boarding begins.
Usually gate bags do not need to be rescreened because they will have been checked along with the passenger through the processes needed to reach the gate.
Hold Baggage Screening
Once bags have entered the baggage system, generally they will be screened using in-line x-ray machines [also known as explosive-detection systems (EDS)] to ensure that dangerous or prohibited items are not present. A typical European screening process is
shown in Figure 7.7. Uncleared bags are examined by a level 1 hold-baggage-screening (HBS) machine. These machines typically can process bags at rate of more than 1,000 per hour. If the machine and its image-processing algorithm is able to determine that there is no threat present, the machine will clear the bag. For perhaps 30 percent of bags, the image-processing algorithm will not be able to clear the bag confidently, so the image will be passed to a human operator for a level 2 decision. In most cases the bags then will be cleared, but typically 5 percent of all incoming bags will still be unresolved and will require a more detailed examination. These bags will be sent to a level 3 HBS machine, which uses computed tomography to give a three-dimensional image, allowing a more thorough examination by an operator. Level 3 machines typically have a throughput of 150 bags per hour. In the vast majority of cases, no threat will be present, and the operator will clear the bag. In a very small fraction of cases, the images taken at level 3 still will be inconclusive, and the bags will be sent to level 4, where a physical examination of the bag will be carried out.
FIGURE 7.7 Multilevel screening protocol.
The multilevel protocol adopted in the United States is as follows:
Level 1 screening is performed with EDS units. All bags that can physically fit in an EDS unit are directed to level 1 screening and scanned using an EDS. All bags that automatically alarm at level 1 are subject to level 2 screening.
During level 2 screening, Transportation Security Administration (TSA) personnel view alarm bag images captured during the level 1 EDS scan and clear any bags whose status can be resolved visually. All bags that cannot be resolved at level 2 and all bags that cannot be directed to level 1 because of size restrictions are sent to level 3 screening.
Level 3 screening is performed manually and involves opening the bag and the use of explosive-trace-detection (ETD) technology. Bags that do not pass level 3 screening
local law enforcement officer.
The TSA has published guidelines and design standards for hold-baggage screening that provide an excellent introduction to the U.S. implementation of hold-baggage screening (TSA 2011).
Bag Storage
Originally, baggage-handling systems had no need to provide bag storage—bags for a flight were accepted at checkin only when the flight makeup positions were available for use, typically two to three hours before the scheduled departure time. Over time, the need for additional bag storage has increased. One factor is the growth in transfer traffic, which can mean that an inbound flight and its connecting bags arrive well before the planned flight makeup positions for the departing flight are open. Another reason is the desire to allow passengers to check in bags when they choose. And increasingly, bag stores can be used to manage and buffer the flow of bags to flight makeup positions, thereby enabling more efficient use of staff and infrastructure or even supporting robotic loading systems (e.g., at Schiphol Airport).
Flight Build and Aircraft Loading
Bags that have been processed and sorted ultimately are delivered to outputs where they are loaded either into ULDs or trailers. ULDs are containers into which bags and cargo can be loaded.
The number of makeup positions allocated per flight will depend on the expected volume of baggage, the flight build time, and the number of segregations into which bags have to be sorted. This can vary from one or two positions for small aircraft to 10 or more for larger aircraft with complex terminating and transfer products.
Smaller aircraft (e.g., B737s, B757s, and A319s) are not containerized, and bags for these types will be loaded into trailers. These trailers then are towed to the aircraft side, and the bags are loose loaded into the aircraft hold using a belt loader. Since this type of operation is relatively slow and labor-intensive, it becomes unsuitable for dealing with the number of bags carried by larger aircraft.
Larger aircraft (e.g., A330s, A340s, B777s, B747s, and A380s) are equipped to carry ULDs. A ULD might be able to contain 30 to 50 bags depending on bag size and ULD type.
There are many varieties of ULDs, but two are very commonly used: AKH and AKE (Figure 7.8). A single AKH can fit across the width of the hold of an A320, whereas a pair of AKEs can fit across the width of a hold of a B777, a B747, and an A380.
FIGURE 7.8 AKE and AKH ULDs.
The flight build process can be very simple, particularly for small, non-containerized aircraft where there are not many bags to be loaded. However, with larger, containerized aircraft and for airlines with more complex products, the flight build involves ensuring that bags are sorted and loaded by segregation. Segregations might include some or all of the following:
• Premium terminating
• Economy terminating
• Crew bags
• Short-connect transfers
• Long-connect transfers
• Interterminal transfers (by departure terminal)
• Onward transfers (by transfer destination)
Loading bags according to these types of segregation assists the speed and ease of handling at downstream stations, but at a price. The flight build operation becomes larger and more complex, and the filling efficiency of ULDs generally will be poorer because some ULDs will be only partially filled. Thus, build segregation policies depend on airline priorities and products, handling operations, and facilities at originating, terminating, and transfer airports.
Irrespective of how bags are loaded into trailers or ULDs, most control authorities require airlines to ensure that all hold-loaded baggage is accounted for. This means recording which bags have been loaded and ensuring that the required security processes
have been complied with for each and every bag.
At its simplest, this can be managed by the bingo-card method. This just means removing one of the self-adhesive bag tags from the loaded bag and sticking it onto a record sheet and reconciling the resulting list of bags against passengers. For small flights, especially without any inbound transfer connections, this is often sufficient.
However, for larger fights and those with inbound connecting passengers, this becomes increasingly impractical. A typical reconciliation system will consist of a number of hand scanners for use by handlers that are connected to a database and message- handling system. The handler scans the bar code on the bag tag and waits for confirmation that the bag may be loaded. The scanned tag number is matched against records in the database, and if the security status is satisfactory, the reconciliation system will indicate, usually via the hand scanner, that the bag can be loaded.
The reconciliation system generally will record other data about the bag, such as the registration number of the ULD into which it will be loaded and the sequence number of the bag within the ULD. This additional information is useful for identifying where to locate a bag if the bag has to be offloaded because, for example, the owner of the bag fails to board the aircraft. The reconciliation system usually will exchange messages with the baggage- handling system and an airline’s departure control system (DCS) in order to maintain an up-to-date status of both bag and passenger. Filled ULDs then are taken to the departure stand and loaded onto the aircraft (Figure 7.9).
FIGURE 7.9 Loading ULDs onto an aircraft.
Arrivals Reclaim
The function of reclaim is to reunite passengers and their baggage. Since the arrival processes for passengers and baggage are very different, the reclaim hall functions as a buffer space—for passengers to wait for bags and for bags to wait for passengers.
Ideally, the appearance profiles of passengers and bags at reclaim should be similar.
This ensures that neither the reclaim device nor the reclaim hall becomes too busy with bags and passengers, respectively. This can be assisted by inbound segregation of premium baggage. Such baggage is unloaded from the aircraft first and delivered promptly to reclaim so that premium passengers, who usually leave the aircraft first and may take advantage of fast-track routes, have little or no wait.
However, there are times when the appearance profiles of passengers and bags are not so well matched. There are two extreme cases: All passengers arrive before any bags are delivered, and all bags arrive before any passengers arrive. In the first case, all terminating passengers have to wait for their bags (and queuing space has to be provided for all these passengers adjacent to a reclaim). If there is not sufficient space for passengers in the hall, then operational measures have to be taken to limit access to the hall to prevent overcrowding. A side effect is that reclaims may be filled with bags whose passengers cannot enter the hall, leading to gridlock.
The second case is that passengers are delayed (perhaps at passport control and immigration checks) and cannot reach the reclaim hall. Initially, bags can be delivered and accumulate on the reclaim device, but because a reclaim typically may be large enough to hold only around 25 percent of the all bags from a flight, baggage handlers then will be unable to deliver further bags. The operational response to this type of situation is to have staff in the reclaim hall remove bags from the reclaim device and stack them in an orderly fashion adjacent to the reclaims ready for passenger collection. This allows the handlers to complete the delivery operation and to be redeployed for subsequent tasks. If this does not happen, handlers cannot be redeployed, and as a result, subsequent arrival and departure activities may be delayed, leading, in extremis, to another form of gridlock.
Transfer Input
Transfer bags need to be processed and, if on a minimum connection time, processed rapidly. To enable this, bags should be loaded into segregated ULDs on the inbound aircraft at the outstation. These short-connect ULDs then can be unloaded as a priority from the aircraft and taken to transfer input locations. Bags then are removed from the ULDs and input into the baggage-handling system. Once the bags have been accepted by the system (oversize and/or overweight bags will be rejected and need to be processed manually), the baggage system will transport and process them (including screening) so that they are delivered to flight build locations, much like locally checked-in baggage. In some cases, special provision is made for the most urgent bags. This may result in the bag being delivered to an alternative output from which it can be expedited, by vehicle, to a departing flight.
In some jurisdictions, certain categories of transfer bag can be unloaded from an
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.