New metrics for terminal operations: Latest research presented at two international conferences

In four new research papers, we assess vertical efficiency, sequencing and separation, with the aim of recommending new metrics to help ANSPs analyse current arrival operations in TMA and prepare for the deployment of new route structures and operating methods.

The latest developments have been presented at the FAA-EUROCONTROL ATM R&D Seminar in Vienna and at the AIAA Aviation Forum in Dallas, with four papers in total.

The objective is to portray current operations, identify best practices, potential inefficiencies and improvement areas, and assess the impact of potential changes on future operations.

For vertical efficiency, to assess the potential for improvement, the papers consider the vertical deviations to best descent profiles of each airport, in relation with the additional time (level of congestion). For the top four European airports in a 50NM radius area and for more than 200,000 flights, the key results are:

• profiles are generally 2,300ft below the best corresponding profile (median vertical deviation);
• some profiles may be 4,300ft below the best corresponding profile for a same additional time (95th percentile).

One of the papers presented in Vienna reveals a significant variability of vertical efficiency among airports. For instance, below FL70 and at high congestion levels, London-Heathrow shows constant performances while Amsterdam Schiphol shows significant variability.

A paper presented in Dallas includes a detailed analysis per runway and per flows, allowing the identification of potential issues and improvement areas.

For sequencing, to characterise the convergence of arrival flights, we consider the spacing deviation (inter aircraft spacing compared to required spacing) and the sequence pressure (density of aircraft in the sequence compared to a runway slot) at different time horizons. For four busy European airports that are representative of different sequencing techniques, focusing on peak periods, up to 15 minutes to final approach, for 14,000 aircraft pairs, the key results are:

• spacing deviation is ±3 minutes at 10 minutes to final approach (90% containment);
• sequence pressure varies from 1 to 3 aircraft at 10 minutes to final (90 seconds slot, 95th percentile).

There are significant differences among airports (e.g. high pressure close to final for Dublin Airport vs low pressure for Paris-Charles de Gaulle), reflecting the impact of the traffic presentation and traffic mix, sequence ordering and sequencing technique. To learn more download the paper “Spacing and Pressure to Characterise Arrival Sequencing”.

For separation, to characterise the aircraft proximity and dynamicity (time pressure), we consider the exposure to small 3D distance and low closure time (respectively below 2x separation and 2 minutes) in relation to the additional time (level of congestion) and at different time horizons. For five busy European airports, in a 50NM radius area, with 300 000 flights, the key results are:

• exposure of 4.0 minutes for small distance (95th percentile);
• exposure of 3.8 minutes for low closure time (95th percentile).

There are differences among airports (e.g. higher distance exposure for London-Heathrow vs higher closure time exposure for Frankfurt Airport) reflecting the nature of operations (single vs parallel landing runways, holding vs tromboning).

For more information, download the paper entitled “Proximity Versus Dynamicity - An Analysis of Traffic Patterns at Major European Airports”.

This R&D activity started back in mid-2016, building upon and extending existing metrics and challenging the new metrics on varied environments and large sets of data. We also started developing a computing capability at the EUROCONTROL Experimental Centre using our 150 real-time simulation workstations and disseminating results, resulting in eight papers published at international conferences.

The next step for EUROCONTROL is to support a service provider in analysing current operations or in preparing for the deployment of a new route structure or a new operating method, while reinforcing research activities towards new applications and using advanced data science.