Pre-departure flight uncertainty of U.S. Oceanic boundary crossing time

Abstract

Trajectory Based Operations (TBO) will rely on “negotiated flight paths” to satisfy objectives of both individual users (exemplified in their user preferred trajectories) and the whole system to the fullest extent possible in an equitable and efficient manner (optimally). If the strategic negotiation of the flight profiles occurs in the pre-departure phase of flight and the negotiated flight plans are executed strictly, maximum system efficiency and user equity may be expected. However, inherent differences exist when accounting for uncertainty in strategic, pre-departure trajectory prediction and tactical, in-flight trajectory prediction. Namely, differences in time horizons and uncertainty sources: Pre-departure planning has a longer look-ahead time and more uncertainty sources compared to the relatively short look-ahead time (typically less than 30 minutes) and less uncertainty sources for in-flight planning. Short time horizon and tactical uncertainty has been thoroughly studied in the literature. A longer look-ahead time and additiona l sources of uncertainty in pre-departure planning contribute a larger uncertainty associated with the planned trajectory. In this paper, we focus on the trajectory crossing time uncertainty at U.S. Oceanic Flight Information Region (FIR) boundary (entry or exit), which are metering points for tracks and congestion points for flights off the track system. We analyze real data from six months of operations and present the flight crossing uncertainty analysis by comparing the actual crossing times with the flight planned estimates. We also use linear regression models to explain the uncertainty with related factors. It is found that, compared to the in-flight (shorter horizon) uncertainty, which is typically assumed to be a normal distribution; the uncertainty for pre-departure planning is less like a normal distribution and is less well explained with linear regression models.