"The 4DCo-GC project aims at exploring the concept of ""4D Contract guidance and control of the aircraft"" as a step change in air transport operations by providing a more radical and environmentally efficient solution for the management of the airspace. Scientific objectives of 4DCo-GC are to:- model 4D contract concepts (strategic, tactical and emergency levels)- develop algorithms (strategic, tactical planning), process and functions (failure management, emergency separation, …) needed to use 4D contacts- define and develop a global tool architecture to demonstrate and analyse the key operating advantages of the 4D contract concept, including the man's role- elaborate an assessment methodology and metrics to qualify and quantify 4D contract characteristics and performances for the control and guidance of aircraft- perform a real time assessment of 4D contract concepts of operations- organize dissemination and demonstration workshops in from of an external audience- derive from a qualification and quantification work, recommendations for future 4DT system development.4DCo-GC brings together the expertise of 13 European and associated partners coming from 7 countries, for a total budget of 5.7 M€ and a total requested funding of 4.1 M€. This 36 months duration programme of work is built on the results of several past EU programmes and projects. Main results expected out of 4DCo-GC project are technological components (software/hardware/architectures) and recommendations for future 4D trajectories guidance and control systems, addressing several priorities of ACARE. Regarding the short/middle-term expected evolutions of the European air transport system, 4DCo-GC is fully aligned with the orientation of SESAR, and particularly the so-called ""ATM Target Concept""."