Automated Baggage Handling Systems One

Automated Baggage Handling Systems One of the most notable innovations in modern air travel has been the development of automated baggage handling systems. Most major cities have new or redesigned airports that handle ever-increasing flows of passengers and baggage.

Automated baggage handling systems make it possible to handle and track these flows more reliably and efficiently by making it possible to identify each and every bag passing through the airport and to track its position at all times, from the moment it leaves the passenger's hand at check-in to the time that it is reunited with the passenger at the baggage claim carousel.

These qualities of automated systems depend upon using computers to handle enormous amounts of data and make split-second decisions about how to move each piece of baggage in light of all of that data. Automated baggage handling systems are not, however, without significant problems. Because their operation involves handling vast amounts of data and an enormous number of moving parts, including vehicles devoted to handling bags individually, such systems are Byzantine in their complexity. Human experience teaches that all such complex systems prone to breakdowns.

This is certainly true for automated baggage handling systems. In fact, the story of one of the most ambitious projects in building an automated baggage handling system is, to a great extent, a story of repeated failure and failed hopes. The history of failure and frustration that has often followed the implementation of automated baggage handling systems has led to improvements in their design, construction and operation.

The automated baggage handling systems currently being developed for use in newly constructed airports have eliminated many of the problems that plagued their predecessors. In addition, these newer systems are well adapted to meeting one of the most immediate and pressing threats to safe and efficient air travel -- terrorism. Because they can track and identify every bag passing through the airport, automated baggage handling systems can greatly reduce the risk that terrorists will be able to smuggle explosives into the cargo compartments of commercial flights.

If nothing else, the ability of automated baggage handling systems to assure airport security demonstrates that, for all of their problems, they are an absolutely essential aspect of contemporary aviation. How Changing Conditions in Modern Air Travel Necessitated the Development of Automated Baggage Handling Systems The increasing volume of modern air travel made it virtually impossible to continue to handle baggage in the "conventional" fashion.

In conventional baggage handling systems, decisions about the destination and routing of bags is made predominantly by individuals, who must read baggage tags, place the bags by hand onto baggage carrying vehicles, or "tugs," which ferry the bags to waiting planes. This process is replaced in reverse when the time comes to unload planes and distribute the bags back to the terminal. Conventional systems are labor intensive and, therefore, very expensive and often unreliable. Moreover, they cannot be utilized effectively over great distances.

When bags must be moved from one end of a large terminal or concourse to another, time is of the essence. Conventional baggage handling systems simply cannot move quickly enough to accommodate airports built on a gargantuan scale. Gargantuan scale is the order of the day in contemporary airports. Cities compete with each other to serve as "hubs" for one airline or another.

Hub airports must be large, contain many gates, and provide quick turnaround times for both planes and passengers so that the airlines can provide an extensive and ever-shifting system of interconnecting flights. The scope of services that contemporary airports must deliver can seem overwhelming. In 2005, it was projected that, by 2011, London's Heathrow Airport would service 30 million passengers when its Termninal Five was completed and that the airport would employ 84,000 workers. (Coupe, 24). The fact that airlines can be spectacular targets for terrorism also changes the way that airports operate.

As one author pointed out, "[t]he challenge of dealing with such huge numbers is compounded by the ever-present threat of terrorism and the attendant emphasis on tight security." (Coupe, 24). The operators of airports are keenly aware that prospective terrorists may be eager to place explosives in baggage and then to place that baggage on planes. There is a need to identify and analyze each and every bag that passes through check-in and on to a plane.

These changes in airport operation have made it clear that it is impossible to safely operate a large airport without a system that can track each and every bag and move it across terminals and concourses at a rapid pace. This is what the automated baggage handling system can provide. The Basic Elements of the Operation of Automated Baggage Handling Systems When a passenger arrives at check-in, a bar-coded tag is attached to the bag.

The tag identifies the name of the bag's owner, his or her flight number, airline, and final destination. If the passenger is making any intermediate connections those are identified on the tag as well. Once it is tagged, the bag is placed on a conveyor belt which brings the bag towards a mini railway system where it will be routed towards the passenger's waiting plane. (Schloch). The mini-railway system is populated by "destination coded vehicles" ("DCVs"). There is one DCV for every bag.

The DCV is a radio-controlled cart with a plastic tub on the top. The radio transponder permits the system's computers to control the movement of the DCV. The tub can be moved into three positions to automatically load, unload, and carry a bag. The DCVs are controlled by a computer system, which senses the flow of passengers throughout the terminal and dispatches DCVs to the appropriate places. During the airport's peak times, Denver has about 3550 DCVs available.

The DCVs are propelled by linear induction motors that are placed at regular intervals along the track. (Schloh) The conveyor belt holding the bag begins to move when a DCV arrives at the end of the belt, ready to accept the bag. The bag is then propelled into the tub at the top of the DCV. The DCV receives the bag without coming to a complete stop. It only slows down briefly as it passes along the rail line.

As the bag is placed into the DCV, a laser scanner reads the bar code on the tag and transmits information to the computer system, which associates the bag with the DCV on which it has been loaded. The DCV then increases its speed and moves into the rail system. (Schloh). Once the information about the bag and its associated DCV are recognized by the computer, the computer then works to assure that the DCV is routed to the loading area for the correct plane.

Computers control the movement of the DCVs so that they merge with other DCV traffic passing through the system. When the DCV reaches the area near the plane, it exists the system and brings the bag to loading area for the plane. (de Neufville). Early Automated Baggage Handling Systems Early efforts at automated baggage handling systems were undertaken at: the United terminal at San Francisco International Airport; the Rhein-Main International Airport in Frankfurt, and at Franz Joseph Strauss Airport in Munich.

These early systems had some significant differences from the later design used at Denver and elsewhere. The Frankfurt system used only trays that ran on conveyor belts; it did not use any DCVs or any kind of mini-railway network. The San Francisco system used much of the same technology, but it operated on a far smaller scale, using only 1/12 the number of DCVs. (Schloh).

Denver's Failed Effort to Build an Entire Airport Around an Automated Baggage Handling System With the success of limited automated baggage handling systems, momentum was created to attempt more ambitious efforts at automated baggage handling systems. The planners of airports began to think that they could expand the ability of airports to handle passengers and cargo by expanding the efficiencies of their baggage handling systems. Denver became the focus for these ambitious plans. In the 1990s, the city of Denver began planning an entirely new airport.

The project was intended to make Denver one of the leading airports in the United States, if not the world. The airport was to cover fifty-three square miles and was designed to include space for as many as twelve major runways. The total cost of the construction project exceeded $5 billion. (de Neufville, p. 2). The size and construction cost of the Denver airport made an automatic baggage handling system essential.

In order to redeem the cost of building so many runways over such an extensive area, Denver had to be capable of handling large numbers of flights. The best way to assure a high volume of flights was to position Denver as a "hub" airport -- that is, an airport that was used as a transfer point for interconnecting flights. Denver could only succeed as a hub airport if it could provide quick turnaround times in between flights. An automated baggage handling system was essential in reducing turnaround times.

Given Denver's physical size and flight volume, an ordinary system of baggage handling would have simply moved too slowly and would have involved unmanageable numbers of workers. But a fully automated system could, at least in theory, move bags quickly and efficiently enough to make the entire enterprise work. Indeed, United Airlines would not sign a lease to be the principal tenant at Denver until it was assured that the airport would have an effective automated baggage handling system. (de Neufville, pp. 2-4).

The designers of the system focused on speed as its signal characteristic. They promised to deliver a system at which the bags would be moved at speeds up to 24 miles per hour so that the bags from a narrowbody jet could be unloaded and sent to their destinations within twenty minutes. For larger, widebody jets, the delivery time was promised to be thirty minutes. The designers boasted that the system could move a bag from one part of the airport to any other part within ten minutes. (deNeufville, p. 4).

Boeing Airport Equipment, which later changed its name to BAE Automatic Systems, was initially responsible for the design of the automated baggage handling system. BAE's proposed design was the most complex automated system ever designed. BAE systems convinced, Walter Slinger, Denver's Chief Airport Engineer that such an ambitious automated system would work by building a prototype automated baggage-handling system. BAE built this prototype in a 50,000 sq. ft. warehouse near its manufacturing plant in Texas. (Donaldson, 1998). Denver's system included an impressive collection of technology.

It used over 300 desktop computers, a large server that hosted a database essential to running the system, a high-speed fiber-optic network, 14 million feet of wiring, 56 laser arrays, 400 frequency readers, 22 miles of track, 6 miles of conveyor belts, 3,100 standard telecars, 450 oversized telecars, 10,000 motors, among other things. (Schloh, 1996). Each track could, in theory, carry 60 DCVs per minute. The DCVs were controlled by "radio frequency identification" or "RFID." (deNeufville, 1994, p. 3). The design and installation of the automated baggage handling system did not go smoothly.

Problems with the system caused substantial -- and expensive -- delays in the airport's opening. It was originally scheduled to open in October 1993, and delays initially pushed that date back to March or April of 1994. But continuing problems with the baggage handling system prevented the airport from opening even at that later date. The system was not ready and the airport did not open until March 1995. These delays added $500 million in construction and interest costs to the total cost of the project. (de Neufville, 1994, p. 2).

The problems began at the very outset the guiding hand behind the automated system at the outset of the project was Chief Airport Engineer, Walter Slinger. Unfortunately, Slinger died six months into the project. His replacement had a different management style and little knowledge of construction. Moreover, he lacked Slinger's keen commitment to making the system work effectively. This change at the top was indicative of how the rest of the project was going to go.

The problems continued through the construction of the principal facilities for the airport -- its terminals, concourses, runways, and the internal infrastructure that served all of those facilties. In the course of the design, construction and testing of the physical facilities, individual airlines made numerous changes to the facilities that would affect the operation of the baggage handling system, such as adding ski-claiming devices and odd-size baggage elevators.

In addition, the design of the automated baggage handling system at Denver was undertaken after the terminals and runways had already been planned and after their construction was underway. Consequently, the physical specifications of the baggage handling system had to be shoehorned into existing spaces. In many circumstances, the area provided for the baggage handling system was simply not adequate for the system's own requirements. In addition, the contract for the system's design and construction was awarded only twenty-one months before the original opening date.

The short timeframe precluded the designers from undertaking any simulation or physical testing of the full-scale design. (deNeufville, p. 4). Communication problems made things worse. No-one effectively managed the lines of communication connecting city government, the managers of the airport project itself, the designer of the automated baggage handling system, and the airlines themselves. Consequently, coordination among these constituent groups was lacking. This multiplied the problems associated with managing information.

And these information management problems were particularly vexing, given the fact that an automated baggage handling system is largely an enterprise in managing information. There were problems in preserving the contractual relationships among the groups participating in the airport's construction. The original contract awarded to BAE did not comply with municipal rules promoting contracts with minority-owned businesses. BAE had to hire outside contractors to meet this requirement at an additional cost of $6 million.

BAE later lost a contract for providing maintenance because it was unwilling to meet union demands for wages for maintenance workers. (Bartholomew). There were many mechanical problems at Denver, even before the airport opened. Many of these problems were mechanical. The DCVs jammed in the tracks. The conveyor belts were misaligened with DCVs. Baggage was shredded. (de Neufville, p. 4). These manifold problems exacerbated the inherent challenge in designing a system that included so many novelties. The system required synchronization between the conveyor belts and the DCVs.

This was not something that had been done before in ordinary automated baggage handling systems. In ordinary systems, the conveyor belts ran continuously, delivering luggage in a constant stream. In Denver's automated system, the conveyors only moved when there was a DCV in position to receive the leading bad on the conveyor. Thus, the effective operation of the entire system depended upon the efficient and timely delivery of DCVs to the proper locations. (deNeufville, 1994, p. 3).

The software that controlled the movement of DCVs sent empty cars back to the waiting pool instead of terminal building. When a DCV became jammed on the track, the software's initial design shut down an entire portion of the network instead of merely shutting down a section of the track behind the jammed car. In addition, the optical sensors did not work as they should have. When they were dirty, they malfunctioned, causing the computer system to recognize a section of track as being empty when it was not.

Although there had been automated baggage handling systems that served parts of airports, Denver's system included many innovations that had never been tried before. It was the first system that would serve an entire airport. It was the first in which the DCVs would only slow down but would never stop to receive bags. It was the first to be operated through a network of desktop computers instead of through a single mainframe computer. And it was the first to have the capacity to handle oversized bags. (Myerson).

Inexplicably, there was no provision for a back-up system, which would employ conventional baggage handling techniques. There were no tugs for hauling bags in the event that the conveyors and/or railway system broke down. Even more remarkably, there was no system of access roads over which such tugs could run. (deNeufville, p. 4). The system's problems seemed to compound each other as efforts to handle some of these problems encountered problems of their own.

Once problems in the system began to be glaringly apparent, a German consulting firm, Logplan, was hired to evaluate these technical problems and suggest solutions. Logplan developed some effective approaches to these problems. Problems in misreading tags were addressed by adding more laser readers. Problems with the speed and control of the DCVs on the rails were address by adding more controllers, which also made it easier to avoid misalignments with the conveyors.

Despite their effectiveness, these solutions added to costs, slowed the performance of elements of the system, thereby reducing the system's overall cost efficiency. Eventually, the airport abandoned the effort to provide a fully automated system, even before the airport opened. United Airlines only provided a fully automated system for one of its concourses. It used conventional systems, with tugs and baggage carts, at other concourses.

When the airport first opened, the baggage handling systems at Denver served three concourses where covering two main terminals where passengers check and claim their luggage. (de Neufville, pp. 8-9). In the end, the misadventures with the system resulted in grave cost overruns. The city originally budgeted $193 million for the construction of the automated baggage handling system. The final cost was nearly $311 million.

Adding a conventional system contributed an additional $80 million to the project cost, and this did not include the $100 million that had to be spent to re-design the terminals to correspond with changes in the design of the baggage handling system. The entire airport project was notable for its cost overruns, and the automated baggage handling system was the source of the vast majority of those increased costs. (Dubroff, 1994).

Persistent Problems with Automated Baggage Handling Systems The problems in Denver were, in large part, caused by idiosyncrasies in the design of that system. But those problems were indicative of more fundamental challenges that any automated baggage handling system will have to overcome. The most difficult problem that all such systems have to overcome is providing reliable delivery times notwithstanding the enormous technical complexity of the system and the widely varying volumes of baggage that the system has to manage at different times.

The entire automated system can be understood as a "cascade of queues." When a plane is ready to unload its bags, those bags wait in a queue to get on the conveyor. The conveyor will not move until DCV is ready to receive a bag. The DCVs cannot arrive at the end of a conveyor until they have processed through the system. (deNeufville, p. 5). The problem of the cascade of queues illustrates that, in any one situation, it is a challenge to manage the complex operations of the system.

This problem is compounded, however, because there is a wide variety of different situations with which the system must deal. The designers of the system must anticipate hundreds of different scenarios, each with its own complex set of problems, and they must anticipate those problems and develop solutions for them, which are integrated into the system's design. (de Neufville, p. 5).

The way to solve the problem caused by the cascade of queues is "line-balancing." There are numerous "lines" feeding bags into the system, including the conveyor belts that take bags from check in, as well as the conveyor belts that take bags from planes that are unloading. The system has to be designed so that there is sufficient capacity for each and every line that will be feeding bags into the system.

The system will fail if some lines are oversupplied with DCVs while others have bags waiting but no DCVs at all. (de Neufville, p, 7). One of the challenges in designing an automated baggage handling system is dealing with the narrow time windows for delivering bags to their appointed destinations. Automated baggage handling systems use "destination coded vehicles" (DCVs) to assure that bags arrive at the correct plane at the correct time. DCVs are metal carts with a plastic tub on top.

They are mounted on tracks and propelled by linear induction motors. They transport the bags at high speed on a minirailway network. The main challenge in using DCVs comes in synchronizing their movements so that they do not collide or create traffic jams in the minirailway network. This requires a sophisticated system for choosing routes for each DCV. (Tarau 2009, p. 76).

A centralized computer system would be the best way to assure optimal route choice, but, generally, the computational demands of such a system make it practically impossible to make use of centralized computer control. Decentralized computing systems can be used, but they must be programmed in such a way that they will not deliver the most optimal results. Efficiency is sacrificed to making the system function. (Tarau 2009, p. 81).

There are also problems with managing the software when the system is controlled by a network of desktop computers instead of a single mainframe. In any computer system, for networked computers, software must provide multiple levels of error-checking codes to correct problems that arise when.