Arena Simulation Modelling Report

Airplane Arrival and Takeoff Simulation

Objectives and Criteria

This report is intended to address a specific Arena simulation modelling process. The modelling approach and process focuses on the development of runway use. The results of the simulation with regard to key performance factors will be illustrated. Finally, suggestions of how to improve performance indicators with runway and terminal utilisation, WIP, noise pollution and waiting times and queues both in the air and on the ground with access to terminals will be made.
The following objectives will also be addressed:

1. A simulation model with appropriate animations of the airport operating system will be developed.
2. Maintaining the simulation model for 548 hours in order to present the percentage of busy and idle time.
3. The utilisation of the Runway and Terminals on a daily basis during the simulation run will be discussed.
4. The WIP for arriving planes, departing planes and total WIP on one plot over a simulated time of 60 hours will be displayed.
5. On one plot over a simulated time of 60 hours, the number of aircraft in process that have a sound level above 80 decibels will be displayed.

The Approaches and Process of Modelling the Airport Running System

According to the airport system scenario, there are two working types– arrival airplanes and departure airplanes, which are operated in two distinct working processes. Two Create modules are dragged into the model as work process start points-Arrival Point (Kelton, W. D., Sadowski, R.P., Sturrock, D. T., 2003)and Departure Point while setting Time Between Arrivals Type to Random (expo) and Value to 40 in Figure-1. We will discuss the Arrival process modelling first. The fact that when airplanes arrive, they queue in the air waiting for signals from the control tower, is conveyed by dragging a Signal module in advanced process and placing it next to Arrival point. The value and limit of the Signal is set to 1, which defines the number of airplanes released each time.
Once an airplane gets a signal, it can continue to land at runway, so the landing process is added and this process requires a resource which is Arrival Runway (see Figure-2). The Arrival Runway resource is not available for a specific period due to the cleaning and detection activity every 5.5 hours. This information is modelled in the modelling by creating a runway schedule and its Schedule Rule is set to wait which means when the resource is unavailable, the airplanes wait in the loading queue. Schedule Rule dictates when the actual capacity change is to occur, when a decrease in capacity is required for a busy resource unit and this applies only when resource type is Schedule. Furthermore, a schedule named Runway Schedule is built, its Format Type is referred to as Duration, and Durations are specified with two rows, one of which is 5.5 with capacity 1, another one is Normal (15, 3) with capacity 0 (see Figure-3). This will satisfy the requirements of runway close in detection every 5.5 hours.
Taxiing process is set by the following, parameters: Action-delay, expression-expo (10). A Decide process is needed to separate Arrival planes into four groups: terminal1 takes 20%, terminal2 takes 30%, terminal3 and terminal4 each takes 25% (see Figure-4). Every terminal has 5 gates and Arrival and departure planes share these five terminals (see Figure-5). The Decide process named 4terminals has such settings: N-way by chance as its Type and 20, 30, 25 as its Percentages.
Unloading the passengers and luggage at terminals is modeled by a process called unloading. There are four unloading processes which are followed by the ultimate process Dispose.
Departure processes are quite similar to the Arrival ones; therefore, a simple description will be given here: Departure Point, Departure Terminal Options which is a Decide process, four loading process at terminals, a departure taxiing and a Dispose process are created. The Departure Runway resource uses the same Runway Schedule as Arrival Runway does. The two work processes also share these four terminals. Arrival and departure planes sharing terminal resources can be modelled by deploying four Process Modules each of which seize a terminal resource. The processes next to terminals are Decide Modules whose type is 2-way by condition; if Entity’s type equals entity1-Arrival planes; it is routed to dispose, otherwise routed to Departure Taxiing (shown in Figure-6).
Regarding Sound Level of airplanes, we use Assign module to assign sound levels to Entities-Arrival Airplane and Departure Airplanes by adding a new assignment, setting its Type to Attribute, setting its Attribute Name to Entity.SoundExposure, and setting its New Value to Triangular (50, 60,100). By checking WIP and clicking on airplanes, an Entity Summary window will appear; by clicking on plus on the right of User-Defined, one can view Entity.SoundExposure (see the left figure of Figure-7).

The Analysis of Performance of Model and Suggestions

1. Simulate the model for 5, 48 hour replications. Go to Run-Setup-Run Parameters, we set the Replication parameters as the following: Warm up Period-12 hours, Replication Length-48 hour, Number of Replications: 5.
According to the simulation report, the percentage of the time runways is busy and idle states are the following: the percentage of busy time of runways is 100%, idle is 0%.
2. Utilisation of Runways and Terminals on daily basis is shown in Table-1:
3. Run the simulation model on one plot over a simulated time of 60 hours, WIP of arriving planes and taking off planes are shown in Table-2:
4. Assume sound level to the airplanes by assigning Attribute named Entity1.SoundExposure to the airplanes. On one plot, over 60 hours’ simulation run, the total number of planes in process with sound level over 80 decibels is 3(see the right figure of Figure-7).
5. The following results of Simulation we are discussing are based on 5 replications run and Replication Length equaling 72 hours.
From Table-3, we can conclude that two runways are in full use, and terminals are in full use except terminal 3. In order to operate more arriving and departing planes, runways available time should be increased by using alternative runways during the inspection.
WIPs of airplanes in Table-4 show that in average, the number of arriving planes is a bit more than departing planes whereas departure planes has greater Maximum Value than arrival ones.
Queues waiting for Resources are shown in Table-5. Queues waiting for terminal2, 4 are longer than Queues for terminal1, 3. The fact is that terminal 1 takes 20% of both arriving and departing planes, terminal 2 takes 30%, and terminal 3, 4 each takes 25%. Terminal 1 can take another 5% of arriving planes from terminal 2 to make unloading process more efficient. Queues waiting for Runways are considerable in length, which again proves the recommendation of using alternative runways.

Simulation Results from Improved Model

Due to the above discussion, to improve the performance of the airport operation system, there are two methods: one is increasing runways work time using alternative runways during inspecting; another is changing the percentages of terminals’ workload. An improved model is proposed according to these changes. By running the new model, we can conclude that no waiting time for terminals again which is the same as the existing system; Regarding Number Waiting in Queues, the number in Queue waiting for terminal 2 has decreased (in Table-6). WIPs and Utilisation of resource do not improve significantly.

Doubling the Number of Operated Planes

With respect to maintaining or minimising emission levels and doubling the number of the arrival and departure planes, one suggestion is reducing the time of each process. Suppose the arrival and departure of planes conforming to the same exponential distribution times, and try to shorten all process time to half of its original time in the new model. By running the new model, results show that Number in for both types of planes has increased to 3.84 and 2.93 times.

Conclusion

An airport operation simulation model was created in accordance with the requirements. By running the model, runway and terminal utilisation, WIP, noise pollution and waiting times and queues both in the air and on the ground with access to terminals are illustrated and discussed. An improved model is also proposed by analysing the performance of the existing model, and its performance regarding the above categories is also included. Finally, how to double the number of processed airplanes in the airport is given.