What is I-4D? – despite the name, it is not the latest craze for cinema goers, but is in fact the culmination of a smart new air traffic management technology delivered by SESAR (Single European Sky Air Traffic Management Research) with the help of Airbus, Eurocontrol, Honeywell, Indra, Noracon1, and Thales.

February 10, 2012, was the first initial four dimensional (I-4D) trajectory flight starting in Toulouse. The Airbus A320 skipped over most of France, Germany, Belgium, and The Netherlands, and landed in Copenhagen, Denmark, and Stockholm, Sweden, in what was a successful test of the I-4D’s capabilities and adaptability to European skies.

Simple in theory, I-4D is a 4-dimensional trajectory concept working on three dimensions, lateral, longitudinal and vertical, with time as the fourth dimension. The system allows aircraft to hold a constant trajectory through correspondence with ground air traffic controllers via data link, ensuring a smooth and efficient flight path to a merging point. In the case of this trial run, the aircraft was set a merging point near Copenhagen Airport where the A320 performed an optimised descent into Danish airspace. From this merging point, another was set close to Stockholm Arlanda Airport, Sweden, where the aircraft performed an optimised descent landing.

Furthering the implementation of SESAR research developments into European airspace has been of paramount importance since the creation of modern, highly efficient Air Traffic Management Systems. This trial has been the ‘first step’ to reinforcing progress in the implementation of one of the essential pillars of the SESAR programme – “conciliating increasing traffic density with optimum flight efficiency”. Reduction of fuel burn and CO₂ emissions, decreasing delays, and optimising flight paths are at the top of SESAR’s list of priorities. I-4D meets these aims, with predicted results of pan-European implementation leading to a 10% decrease in environmental impact per flight. If this is just the ‘first step’, the second should be superlatively impressive.