Strategic Modelling and Business Dynamics: A Feedback Systems Approach

6.6. Appendix: More About the Fliers Model

A complete equation-by-equation description of the Fliers Model is available within the Fliers Mini-Sim in the CD folder for Chapter 6. Select 'browse model' from the list of buttons on the left of the opening page. A diagram similar to Figure 6.11 will appear. Then click on any model icon to view the accompanying equation and documentation.

The formulations in the market sector of the Fliers model need more explanation than is available on the CD. The equations for available passenger miles are shown in Figure 6.17. Essentially, the more planes owned by easyJet, the more passenger miles the airline can fly each year. Planes are represented as a stock accumulation with an initial value of 12. There is no inflow or outflow to this stock because, in the Fliers model, we are specifically interested in easyJet's $500 million start-up gamble to purchase and fill 12 new planes. Available passenger miles are defined as the product of planes, passenger miles per plane and service days per year. Passenger miles per plane is a measure of the daily travel capacity of a short-haul plane flying between European destinations. For example, a typical 737 aircraft carries 150 passengers and makes three flights of 1000 miles per day for a total travel capacity of 450 000 passenger miles per day. Service days per year is assumed to be 360, meaning that the typical new plane flies almost every day of the year. Hence, the total available passenger miles from ...