Delay Propagation and Multiplier

In the National Airspace System (NAS), many flights are delayed daily as reported in the Air Travel Consumer Report (monthly) by the Bureau of Transportation Statistics, the U.S. Department of Transportation. An initial delay often causes another delay in a subsequent flight, or a propagated delay. This paper examines the delays observed in a sequence of the flights operated with the same aircraft, or the same tail number among the busiest airports and produces a delay multiplier to assess the repercussion of the initial delay on the entire sequence of the flights during the day. The propagation multiplier is frequently used in the context of the cost-benefit analysis to demonstrate how the reduction of the initial delay leads to a greater reduction in the propagated delays and, thus, greater benefits. Furthermore, based on the delay propagation sequences constructed by a tail number tracking methodology for the flight data for the calendar year 2007, we tested the hypothesis that the propagated delays are exponentially distributed by fitting the Weibull or Gamma probability density function and, then, examining to see how close the estimates of the shape parameter are 1. We found that these two distributions over the propagated delays closely follow the exponential distribution.