5.1 Co-Ordination of Flight Activity

Traditionally airline schedules were designed, either for the convenience of local point-to-point passengers, or to meet operational objectives such as maximizing air craft/crew utilization, minimizing airport and station costs, etc. But the emphasis has now clearly changed. As markets become more competitive, more and more importance is attached to co-ordinating arrival and departure times to attract connecting traffic. An important part of this is to concentrate flight activity at the hub into a limited number of peaks, or waves, during the day. Services on the spokes are timed so that they connect at the hub, arrivals preceding departures in sufficient time to permit the transfer of baggage from inbound to outbound flights. Ideally a lot of inbound flights should arrive within a short a space of time and then depart again as soon as some minimum connecting time (MCT) has elapsed. To maximize the potential benefits the amplitude of each wave should be as great as possible. The fewer the number of waves across the operating day, the greater the number of possible connections. The theoretical maximum is achieved only if all flights are scheduled into just one large wave; and in theory, if all flights to or from a particular airport are timed so that a passenger could connect between any two, the maximum number of possible connections would equal the square of the number of flights. The objective here is to maximize the number of useful connections. Not all connections are useful...