New air traffic control tower at London Heathrow
Tue 17 Mar 2009 – Further to the pledge in January by NATS, the UK’s air navigation service provider, to reduce the total emissions by aircraft it controls by an average of 10 percent per flight by 2020, its researchers have now calculated that 26.3 million tonnes of CO2 were produced in UK airspace in 2006, so providing a benchmark to assess its performance. NATS says it is the first company in its sector to create this environmental aim. Chief Executive Paul Barron said that 70,000 tonnes of CO2 had already been saved over the past year through improved airspace management and design changes.
The researchers measured hundreds of thousands of flights over thousands of routes and the resulting analysis has provided the benchmark, which NATS says was the first important step in a long-term plan to reduce the impact of its operations on the environment.
“This is a testing target in challenging times but aviation is making strides to be more sustainable and air traffic control must play its part,” commented Barron. “What this research shows is that we can make a difference.
“Calculating this was an achievement in itself. But we have also identified where the savings can be made – where in the network and in which phases of flight. This is just the beginning but we can see the path to 2020.
“Safety will always be our first priority but environmental responsibility will become part of our day-to-day work. We are determined to take this big step to leave behind a smaller carbon footprint.”
Breaking down the total emissions, the researchers used real radar data and found that over 61% of the total CO2was released by aircraft operating in domestic airspace,around 33% was generated by aircraft within the NorthAtlantic area, and the final 6% came from aircraftoperating on the ground at UK airports where NATSprovides a control service.
How NATS intends to achieve the elimination of 2.6 million tonnes of CO2 per annum is spelt out in a new document it has released called ‘NATS and the Environment 2009’. NATS points to:
· Technological developments in progress for the future include Reduced Longitudinal Separation Minimum, improving opportunities for pilots to request and receive climbs, and aircraft navigation and surveillance improvements.
· Helping to reduce the amount of time aircraft spend queuing in stacks to final approach. Aircraft circling in the arrival holds before they land are estimated to account for 2% of all of the CO2in NATS’ controlled airspace. Three-quarters of these emissions are generated by aircraft arriving at Heathrow, probably a symptom of the airport’s runways operating at close to maximum capacity. 56% of aircraft arriving at Heathrow have to wait to land.
· Reducing aircraft emissions on the ground at airports. Of the 1.5 million tonnes of CO2emitted at the airports where NATS provides a control service 75% is due to taxiing, 14% take-off and 11% ground holding. NATS is working with airlines and airports on the installation of new equipment such as pre-conditioned air to reduce the use of aircraft engines while aircraft are on stand and innovative trials such as towing aircraft to an engine starting point closer to the runway to reduce fuel use. NATS air traffic controllers have also been co-ordinating with airlines and air traffic control at other airports to hold aircraft on stand when there are known delays at the destination airport. Holding on the ground rather than in the air can save around 250kg of CO2per minute.
· Defining the best flight profile for fuel conservation. NATS researchers have identified a fuel-efficient, optimal profile that would minimize fuel use and emissions. Essentially, part of the change will be in delivering more continuous climb and descent profiles, and in cruise, profiles that are closer to optimum.
· Identifying certain inefficient routes between cities and targeting improvements. NATS plans to assess further the routes in these areas to find out why they are less efficient and begin a programme to remedy those that offer the greatest scope for improvement.
The 10% target has been split out to indicate the proportion of improvement expected from each phase of flight. Reducing CO2during descent can contribute 4.75% of the total emissions saving across the UK ATM system, compared to 3.25% during climb, 1.50% during cruise and 0.50% at airports. NATS says greater improvement can be targeted where it is most realistic, for example, in the descent phase.
The baseline assessment identified how the level of CO2 emissions varies across the different types of operation. This is shown in these two charts above. The left-hand chart shows the breakdown of flights handled by NATS in 2006, the right-hand chart showing the breakdown in terms of CO2 emissions. The results are largely explained by the different aircraft types and the fuel efficiency of the different phases of flight in each element. However, says NATS, this information enables informed decisions to be made about how to target improvements to achieve the best reductions in CO2 emissions.
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