Optimized Profile Descent Research Articles

How Air Traffic Control Intervention Effects Altitude Deviations on Optimized Profile Descent Arrivals

U.S. National Airspace System modernization began with the publication of the Next Generation Air Transportation System Integrated Plan (NextGen) in 2004 to accommodate forecast air travel demand increases in the United States. This framework proposed an integrated approach to safety, environmental sustainability, reduced fuel burn, and increased airspace and airport capacity by using automated capabilities. One of these capabilities, the Optimized Profile Descent (OPD) is an automated procedure created to link the en route phase of flight with the terminal area within the context of NextGen goals. This type of automated procedure was developed during the NextGen short phase (2004-2012) for both air traffic control and aircraft, but they continue to be used in a non-integrated manner. It is the confluence of incompatible automated and manual air traffic management techniques that produce a favorable location for an altitude deviation. The purpose of this study is to determine the effect of air traffic control intervention on altitude deviations reported during optimized profile descent arrival procedures in the U.S. National Airspace System from January 1, 2012 to January 1, 2018. Examination of aviation safety reports from this time period showed that air traffic control intervention did effect altitude deviations, specifically in the areas of aircrew error, communication error, and equipment malfunction or limitation. This analysis also demonstrated the failure of the altitude deviation rate to return to normal historic levels after the introduction of NextGen procedures, making altitude deviation a leading safety indicator for the U.S. National Airspace System.

Optimal Metering Point Configurations for Optimized Profile Descent Based Arrival Operations at Airports

Optimized profile descent (OPD) is an arrival procedure for the Next Generation Air Transportation System, which has been demonstrated to effectively decrease noise, emissions, and fuel costs. Implementation of OPD operations requires effective metering policies because of the increased role of uncertainty in aircraft trajectories during descent. While optimal sequencing and spacing of OPD flights have been studied in the literature, any potential savings resulting from possible changes in metering point configurations have not been addressed. In this paper, we develop models to further increase the value of OPD operations over conventional arrival procedures by optimizing metering point configurations, which include identification of the optimal number and locations of metering points to use during OPD. We derive an algorithmic framework based on implementations of a stochastic dynamic programming model and a nonlinear stochastic integer program to identify best metering point configurations where resulting computational difficulties are addressed through convex approximation and Lagrangian decomposition procedures. We also describe numerical results based on actual traffic information at major U.S. airports, which indicate that the total potential savings in the top 10 major airports could be up to $22 million a year if the proposed policies are implemented. The online appendix is available at https://doi.org/10.1287/trsc.2017.0788 .

Value of Extended Time-Based Metering for Optimized Profile Descent–Based Arrival Operations

As one of the key components of the implementation plan for the Next-Generation Air Transportation System, time-based metering delivers a more precise trajectory and has been shown to be more efficient than distance-based metering. In addition, by adding metering points upstream in en route space, extended time-based metering can help reduce flight trajectory deviations at metering points. With these advanced metering procedures, a well-designed metering configuration can improve the efficiency of arrival operations such as optimized profile descent (OPD). This paper aims to identify the optimal metering point configurations for OPD operations at airports on the basis of an extended time-based metering concept, as well as the value of such metering in OPD. To this end, the paper adapts a two-phase algorithmic framework to identify the number and locations of metering points under the extended time-based metering setup. Extensive numerical simulations based on OPD implementations at Atlanta (Georgia) International Airport are performed for different extended metering ranges and average arrival rates. Optimal time-based metering configurations are obtained for different extended metering ranges, and corresponding savings are provided. Marginal savings from additional metering ranges are shown to be decreasing, and it may not be value-adding to increase the extended ranges above a certain level. The results are further generalized to the top 10 major airports in the United States, and estimated savings attributable to optimization of extended time-based metering points are calculated to be around $33.4 million, an additional 14% improvement on fuel efficiency over current OPD operations. In addition, the value from usage of extended time-based metering is shown to be around $4.2 million for the top 10 major airports compared with the use of distance-based metering methods.

Lower Cost Arrivals for Airlines: Optimal Policies for Managing Runway Operations under Optimized Profile Descent

Optimized profile descent (OPD) is an operating procedure being used by airlines to improve fuel and environmental efficiency during arrival operations at airports. In this study, we develop a stochastic dynamic programming framework to manage the sequencing and separation of flights during OPD operations. We find that simple calculation based measures can be used as optimal decision rules, and that the expected annual savings can be around $29 million if such implementations are adapted by major airports in the United States. Of these savings, $24 million are direct savings for airlines due to reduced fuel usage, corresponding to a potential savings of 10%–15% in fuel consumption over current practice. We also find that most of these savings will be due to the optimal spacing of OPD flights, as opposed to the optimal sequencing policies which contribute only 14% to the total savings. Hence, optimal spacing of OPD flights is much more important than optimal sequencing of these flights. We also conclude that there is not much difference between the environmental costs of fuel‐optimal and sustainably‐optimal spacing policies. Hence, an airline‐centric approach in improving OPD operations is likely to be not in conflict with objectives that might be prioritized by other stakeholders.

Optimized Profile Descent Arrivals at Los Angeles International Airport

The optimized profile descent is an example of one of the many NextGen technologies under development to modernize and increase the efficiency of the national airspace system. The first publicly charted optimized profile descent procedure was implemented at Los Angeles International Airport in December 2007. This new flight procedure was designed so that aircraft could conduct arrival and approach operations with the engines remaining at or near minimum idle power settings; thereby, saving an average of 25 gal of jet fuel per flight when compared to the various aircraft types conducting an arrival and approach along the same lateral path at Los Angeles International Airport. This optimized profile descent translates into annual reductions of approximately 2,000,000 gal of jet fuel and 41,000,000 lb of carbon dioxide emissions. Given the positive environmental benefits of an optimized profile descent, there are several projects underway to increase the use of environmentally friendly arrival procedures within the national airspace system. The aforementioned achievement at Los Angeles International Airport has motivated and enabled new optimized profile descent procedure designs for Atlanta, Miami, Charleston, and Phoenix.