A new approach to baggage handling at airports
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Summary
Airports and airlines are concerned with the task of baggage handling: organizing that the baggage of check-in and transfer passengers is loaded into the right aircraft on time. Since all the baggage arrives at different moments at different locations it often is buffered (temporarily stored) before it can be directed to the unloading quays (laterals or carousels). Baggage handling comes along with costs which airports / airlines try to minimize.
Nowadays baggage handling systems rely on the push concept. The push concept uses standard algorithms to handle baggage. This means that a fixed period before departure the baggage is transported from the buffers to the laterals where it is loaded in containers in order to transport the baggage to the platform. Because of these fixed algorithms the flexibility and efficiency is low; when there are no bags available in the buffer a lateral opens anyway and is empty for a long period. When there are many bags available in the buffer and a lateral is available for handling baggage, the system waits until a fixed period before departure of the flight with opening the lateral and handling the bags. This results in the fact that capacity is not fully utilized.
For this reason the pull concept is introduced. The pull concept handles the baggage in batches when it is available and a lateral is currently not operating. This can result in a higher utilization of the laterals which will reduce the cost for baggage handling. The main research question is: How can the
introduction of the pull concept in baggage handling systems, as opposed to the push concept, improve the efficiency of these systems?
To come to an answer on this research question four steps are taken: 1. Analysis of baggage handling systems and their environment 2. Problem definition
3. Comparing the push and pull concepts 4. Applying the pull concept
This research starts with analyzing baggage handling systems, its processes and the different baggage flows. Before baggage can be loaded into an aircraft it undergoes the following processes (depending on baggage type and time of arrival): labeling, screening, tubbing, sorting, transporting, loading and buffering. The following baggage flows can be distinguished: originating baggage, transfer baggage, primary and secondary flow baggage, tubs and ULD’s and carts.
Subsequently the environment of baggage handling is considered. It has become clear that there are four major stakeholders in the field of baggage handling: passengers, airports, airlines and baggage handlers. Passengers, airports and airlines benefit from the introduction of the pull concept whereas baggage handlers have divided opinions. On one hand they support pull systems since these systems improve baggage handling systems, on the other hand pull systems decrease their freedom with respect to planning of the work; they lose control since the system decides what happens and when this happens.
The most important key performance indicator (KPI) in baggage handling is the average cost per handled bag and therefore this research is focused on decreasing the value of this KPI. The pull concept, as opposed to the currently used push concept, gives the possibility to realize this.
To compare the push concept with the pull concept two simulation models (one of the push and one of the pull concept) can be used. These simulation models give the user the opportunity to specify its own baggage handling system and calculate the needed equipment, number of mishandled / delayed
A new approach to baggage handling at airports
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bags and number of employees needed. These calculations are based on the input of the user and the used departure and transfer schedules.
The output of the simulation models are used as input in the created cost model. This cost model calculates the average cost per handled bag.
This cost model shows that the cost per handled bag can be decreased by the pull concept. Based on the cost model and the simulation models the average cost per handled bag is €3,05 for the push concept and €1,81 for the pull concept for buffering and making-up the baggage. The total reduction of the cost for AAS in the year 2005 (AAS handled 44,2 million passengers, indicating that there were 22,1 million departing passengers) would have been €1,24 * 22.1 million = €27,5 million if the airport is assumed to have one baggage hall. In reality AAS has more baggage halls and the effects of the pull concept on the other baggage halls (then the E-hall which is examined in this research) will be different.
The biggest cost saving is the decrease in the number of employees needed to handle the bags. The push concept is cheaper in its functionalities (caused by a smaller size of the Direct Access Buffer) but overall more expensive.
Since the pull concept relies on batch-loading the driving logistics get more complicated, this depends on the used batch-size: the smaller the batch-size the more complicated the driving logistics get.
Extra experiments show that there is room for improvement of the design of a baggage handling system based on the pull concept. Furthermore they show that the capacity at the laterals (in terms of number of employees) is a crucial factor, especially if the batch-sizes are compared. The distances from the infeed stations to the laterals are getting more important for smaller batch-sizes.
The main research question can be answered as follows: Based on the performed simulations it can
be concluded that the introduction of baggage handling systems based on the pull concept can reduce the cost of baggage handling. However, not every BHS based on the pull concept is cheaper than a BHS based on the push concept. Therefore, pull systems should be carefully designed and tested before they are implemented. The capacity of employees is a crucial factor in determining the cost for baggage handling, further research to this factor would improve the reliability of the outcomes of the simulation models.
It is recommended to do more experiments in order to improve the pull concept (the push model can be used in order to improve the push concept). The pull model can be improved by also pulling batches of bags out of the Early Baggage Storage as opposed to only pulling these batches out of the Direct Access Buffer. Furthermore assigning laterals should happen based on the locations of these laterals.
Finally, the following recommendations for further research are made: • The introduction of the pull concept in the process of screening. • The cost structure of baggage handling systems.
• The pull concept in combination with mechanized loading.
• ARBO-rules concerning the capacity of employees and the possibility to hire employees for only a part of the day.
