ASSIGNMENT

Assignment

Assignment

Introduction and Rationale

The role of the runway controller in the simulation is performed by a search which was designed to form the basis of an online decision support system. Both the simulation and the decision support system are fully described in the paper. We use the results to evaluate what effect upon delay we would expect from various changes that could be made to the departure system. We end the paper by drawing conclusions about the predicted effectiveness of different changes that could be made to the departure system and focus upon a further opportunity for a decision support system. In this paper we focus upon the departure system for London Heathrow airport, one of the busiest airports in the world. Decreasing the delay for aircraft awaiting take-off with their engines running would decrease fuel usage and have consequent cost and pollution benefits. In this paper we explain how the departure system at Heathrow currently works and the various constraints that apply to take-off schedules. We present a model for the take-off order problem from the point of view of the runway controller, the person who currently performs the take-off scheduling. We investigate the effects of each constraint and combination of constraints, using a simulation of the Heathrow departure system.

The amount of reordering that is possible is limited and depends upon the structure of the holding points in use at the time. The take-off order can greatly affect both the throughput of the runway and the consequent delay upon departing aircraft as there are restrictions upon the minimum gap that is necessary between departing aircraft. At London Heathrow there are two runways available. However, for reasons of noise control, only one may be used for arrivals at any time, meaning the other is available for departures. Departing aircraft taxi from the stand, by the terminal, around the taxiways to holding point structures near the end of the current departure runway. There they are reordered for take-off by a runway controller. These holding points are different for each runway end and comprise one or more entrances from the taxiways, some manoeuvring space and one or more exits onto the runway.

Aircraft that take off have to maintain a given safe separation distance in flight. To ensure that the in-flight separation distance will be attained, a second type of minimum separation time is also required between aircraft at take-off. Aircraft depart along specific, pre-defined departure routes called Standard Instrument Departure routes, or SIDs. This second separation depends upon the departure routes of the aircraft; a larger separation being needed if routes are similar than if they diverge very quickly. It can be worked out from the SIDs of the two aircraft and is then modified by the speed groups of the aircraft to allow for divergence or convergence in flight due to the following aircraft being slower or faster than the preceding one; the modification rules also depend upon the SIDs that are being ...