A recently completed live trial at Paris Orly has evaluated a new technique to optimise continue descent operations (CDO) in high traffic density and to reduce the noise of aircraft as they approach the airport for landing. Run by DSNA in collaboration with Eurocontrol and airlines, the trial involved around 500 commercial flights, which were sequenced until common point after which they followed a single air navigation (RNAV) trajectory to intercept the instrument landing system (ILS). To measure potential gains in terms of noise abatement, DSNA positioned 12 noise stations along the flight route.

Today, procedures based on vectoring onto the airport’s Instrument Landing System (ILS) leads to traffic dispersion at low altitude and stepped descent (level-offs), resulting in fuel inefficiencies and noise pollution for local communities. The new SESAR operational technique relies on connecting a single air navigation (RNAV) trajectory to ILS and providing a clearance to intercept ILS from FL100 until 4000’, allowing the flight crew to freely optimise the vertical profile according to the aircraft characteristics. This technique allows aircraft to perform a CDO to the airport, resulting in fuel efficiencies, CO2 reduction but above all noise abatement.

To validate the technique, a live trial was carried out between 2 and 13 November 2015 involving over 500 flights inbound to Paris Orly for RWY 26 approach. Overall, the trial culminated in 33 hours of validations which provided realistic operational conditions in terms of the variation of traffic and weather.

To prepare for the trial, extensive preparations were carried out by Orly Airport and environmental experts from DSNA. Simulations were also carried out in advance of the live trial at Eurocontrol’s experimental platform in Brétigny to allow a dedicated team of controllers to test the procedure before launching the validation activity. Finally, airlines were involved through operational information processes, such as SUP AIP, NOTAM.

Globally, the benefits expected of this technique can be summarised as:

Safety

• Reduction of non-stabilised approaches (RNAV trajectory connecting to ILS)
• Reduction in the need for radio communications and frequency load (no ATC vectoring instructions for ILS interception)

Noise abatement

Avoidance of traffic dispersion and reduction in overflown inhabitants (positioning of RNAV trajectory avoiding populated areas)

Flight efficiency

Reduction of level-offs and optimised profiles (distance to go known once cleared to ORTOL)

An innovative aspect of this exercise has been its focus not only on flight profile optimisation, but also on designing a technique in such a way as to reduce noise impact by enabling the aircraft to avoid the most populated areas of cities. To put the technique to the test, 12 noise stations were positioned along the flight route. The project then tested the noise impact of the traffic flying using the SESAR technique procedure compared to the noise caused by traffic applying today’s procedures.

The final results of this exercise will be released in 2016 as part of SESAR JU’s Release 5.