Operational initiatives

The 2035 ambition level (section 4.2) is to be reached by implementing various operational initiatives.

Free Route Airspace

Free Route Airspace is defined as that airspace within which users may freely plan a route between any defined entry and exit point, subject to airspace availability. Figure 4.6 provides an overview of Free Route Airspace (FRA) and direct routing implementation in Europe as of the end of 2018. It fosters the implementation of shorter routes and more efficient use of the European airspace. The proportion of flight time flown in Free Route Airspace during 2017 was 20% compared to 8.5% in 2014. Since 2016, it should also be noted that cross‑border free route activities have been implemented in Estonia, Latvia, Italy, Malta, Slovenia and Croatia. The Network Manager estimates 2.6 million tonnes CO2 savings from the implementation of FRA since 2014.

Continuous Climb Operations / Continuous Descent Operations

In 2015, harmonised definitions, metrics and parameters to measure Continuous Climb Operations (CCO) and Continuous Descent Operations (CDO) in Europe were agreed by a Task Force of European ATM Stakeholders. These included the definition of a ‘noise CCO/CDO’ and of a ‘fuel CCO/CDO’. The fuel CCO/CDO measures the vertical flight efficiency, in terms of fuel and CO2, for the entire climb and descent profile respectively. The noise CCO/CDO measures the vertical flight profile efficiency to 10,500 ft for CCO and from 7,500 ft for CDO, which are the phases of flight where the primary impact is considered to be noise.

A European-wide study [62] of current CCO/CDO implementation, based upon the agreed definitions, was subsequently performed in 2017 where flights with level segments (a proxy for inefficiencies in the climb and descent phases of flight) were measured and their fuel burn, CO2 and financial impact estimated.

Figure 4.7 and Figure 4.8 use a sliding scale to indicate the average amount of time flown in level flight for both the noise and the fuel CCO/CDO at selected European airports in 2017. The scales for the noise and fuel CCO/CDOs are different, based on minimum, average and maximum values, illustrating the relative performance between the airports. Note that the average amount of level flight flown on departure (noise CCO) is relatively low at 5 seconds compared to 67 seconds for arrivals (CDO).

Within the scope of the fuel CCO and CDO definition, the average amount of level flight flown by all European flights is 44 seconds for departures (CCO) and 165 seconds for arrivals (CDO). Figure 4.8 shows that there is there is a relatively high amount of level flight within the European core area, indicating a link between CCO/CDO and airspace complexity.

The results indicate a greater potential to reduce noise and fuel use during descent (CDO) compared to climb-out (CCO), and overall the room for improvement is less in the noise CCO/CDO compared to the fuel CCO/CDO. The ability to perform CCO/CDO profiles also appears to be linked to airspace complexity rather than airport capacity. The results also indicate that a typical flight with level segments could benefit on average from CO2 savings of up to 48 kg for a CCO and 145 kg for a CDO, reflecting the higher CO2 penalties caused by inefficiencies in the descent phase. The potential CO2 benefits from optimising European wide CDOs were estimated to be ten times more than those of optimising CCOs. Furthermore, there is a much smaller potential to optimise the noise CCO/CDO compared to the fuel CCO/CDO. Acknowledging that the optimisation of environmental benefits depends upon local conditions, it was concluded that CCO/ CDO implementation should, where possible, focus on the optimisation of the flight profile from top of descent.

The total potential savings in Europe is up to 350,000 tonnes of fuel, which is equivalent to 1.1 million tonnes of CO2 emissions per year. However, it should be noted that the ability to fly 100% CCO or CDO may not be possible for a number of reasons such as safety (i.e. time or distance separation), weather or capacity.

Implementation of Airport Collaborative Decision Making

Airport Collaborative Decision Making (A-CDM) aims at improving the overall efficiency of airport operations, especially on aircraft turn-round and pre-departure sequencing processes.

Increased predictability can be of significant benefit for all major airport and network operations by improving flow management and sector planning. This is achieved by the Network Manager receiving more accurate target take-off times from the airport. On average, the implementation of A-CDM enables a reduced taxi time of 1 to 3 minutes per departure [63].

A further 16 airports (Figure 4.9) have implemented A-CDM since 2016, resulting in 40.9% of European departures operating from a A-CDM airport. The 2016 A-CDM impact assessment report [64] identified savings generated from 13 of the 17 A-CDM airports that have demonstrated tangible taxi-time performance improvements of 108,072 tonnes of CO2 emissions.

Additional operational initiatives

Further solutions which are expected to provide substantial environmental savings are highlighted in Table 4.1.