NATS hopes to continue improving fuel efficiency improvements, but its 3Di scheme does not take noise into account

According to UK air traffic services provider NATS, the environmental and operational efficiency of UK airspace improved during the first half of this year. However, it faces a challenge to meet a new tighter year-end target set by the CAA. In 2012, NATS was set an incentivised efficiency performance target (called 3Di -meaning 3 dimensional inefficiency) by the CAA. Its aim is to get the most direct and most fuel efficient routes, saving aircraft having to stack, and cutting fuel use and CO2 emissions. Each flight is given a score of its efficiency, with zero being best. Most flights typically score between 15 and 35. This year the CAA set NATS an overall target of 23. Their score was 23.7 in 2013 and a score of 23.9 in 2012. NATS says it it achieves its target scores over 3 years, planes will have saved around 600,000 tonnes of CO2 will have been saved. As well as CDA (continuous descent approach) landings, smoother take-offs, and flying at the optimum level. NATS is straightening flight paths. Their 3Di scores to not take account of the noise nuisance, and there are fears that some new flight path changes, helping NATS meet their target, are creating more noise from over-flying new areas.


NATS says of 3Di:

“The flight efficiency metric, known as 3Di, forms the cornerstone of a new incentive regime which is designed to deliver 600,000 tonnes of CO2 savings over the next three years, worth up to £120m in today’s fuel prices.

The introduction of the metric follows several years of developmental work by NATS in consultation with airline customers and the UK’s specialist aviation regulator, the CAA. The 3Di metric will help air traffic control route flight paths as close to the environmental optimum as possible by accurately measuring the efficiency of each flight in UK airspace.”

UK airspace environmental and operational efficiency continues to improve but NATS faces challenge

15 Aug 2014 (Greenair Online)

According to UK air traffic services provider NATS, the environmental and operational efficiency of UK airspace improved during the first half of this year. However, it faces a challenge to meet a new tighter year-end target set by the UK Civil Aviation Authority (CAA).

In 2012, NATS became the first ANSP [Air Navigation Service Provider] to be set an incentivised efficiency performance target by its regulatory authority [the CAA].

NATS measures the route and trajectory of every aircraft flight within UK airspace using its three-dimensional inefficiency (3Di) metric, with each flight compared to a scale where zero represents total environmental efficiency. Most flights typically score between 15 and 35. During the January to June 2014 period, NATS achieved a rolling average score of 23.3, lower than the score of 23.7 for 2013 but higher than the 2014 target of 23 set by the CAA.

In the first year of the performance index, 2012, NATS achieved a 3Di score of 23.9 against a target of 24. If NATS achieves its target scores over the three-year period, around 600,000 tonnes of CO2 will have been saved.

“We’ve seen a gradual reduction in 3Di scores so far this year, demonstrating that UK airspace efficiency is improving, but we still have more to do to achieve the CAA’s target value by the end of the year,” commented Ian Jopson, NATS’ Head of Environmental Affairs.

“We’re currently focusing on a number of small scale airspace changes, as well as extending the flexible use of airspace with military users and further improvements in continuous descent approaches.”

According to NATS, its air traffic controllers can help earn a lower 3Di score by providing direct routes, smooth continuous climbs and descents, and optimum flight levels. Factors that can negatively affect the score include the weather, the volume of flights within the network and limited runway capacity leading to aircraft holding.


NATS – Environmental Performance

NATS reports 800,000 tonnes of carbon savings over five years since launching its environmental programme




This NATS webpage states:

The commentary includes :

Last year NATS made significant steps towards reducing arrival holding through the implementation of a descent speed trial.  Reducing holding by slowing aircraft down en route reduces the need for aircraft to ‘hold’ close to an airport, circling, burning extra fuel and generating more emissions.  As a result of this activity, and over 75 other airspace efficiency initiatives, flight profiles improved during 2013, resulting in a reduction in 3Di Scores.

NATS is focusing its efforts on delivering improved airspace efficiency in order to achieve its tougher 3Di targets for the end of 2014.  We are now embarking on:
  • A number of small scale airspace changes
  • Extending the flexible use of airspace with military airspace users
  • Further improvements in continuous descent approaches
  • Additional procedures and tactical changes to deliver optimised trajectories
  • Environmentally focused network management improvements

Despite these measures, meeting our new tighter 3Di target by the end of this year will take significant effort and innovative thinking drawing on all the knowledge and expertise of our front-line operational staff.”

 [There is no mention of noise, at all, on this page].


An AirportWatch member comments: 

I wonder if the “small scale airspace changes” include things like cutting the corner to overfly Warnham ?

A quick skim through the NATS report shows it is evident that they are heavily incentivised to score well in the 3Di metric for environmental performance.  But the metric includes nothing about noise impacts – it is all about fuel saving.  So the airspace changes they are forcing through will boost the NATS bonus at the expense of noise hell for people below.

NATS needs to address the noise issue too. They may only be persuaded to do this from pressure by the Government and CAA.




XMAN trial aims to cut LHR holding times

A new operational procedure to cut the amount of time aircraft circle in ‘holding stacks’ at London Heathrow Airport is set to begin today.

Traditionally NATS, the UK’s air traffic service provider, has only been able to influence an arriving aircraft’s approach to Heathrow once it enters UK airspace – sometimes only 80 miles from the airport. This limits the opportunity to manage the flow of traffic and can result in additional time spent in the holding stacks.

From today, if delays in the Heathrow holding stacks begin to build, air traffic controllers in the Netherlands, France, Scotland and Ireland will be asked to slow down aircraft up to 350 miles away from London to help minimise delays on arrival.

The trial is being led by NATS in close cooperation with French air traffic control provider, DSNA, the Maastricht Upper Area Control Centre and Prestwick Control Centre, with the aim of cutting average holding times by at least a quarter from the current time of just under 8 minutes.

In a pre-trial test of the system, the first ever live data – flight BAW74 – was passed between NATS and French air traffic controllers at DSNA’s Reims control centre in the early hours of 21 March 2014.

Martin Rolfe, managing director, operations at NATS, commented: “This is the first cross border arrivals management – or XMAN – trial of its kind anywhere in the world and a great example of partnership working for the benefit of our customers and a potential future model for the industry. We expect the trial to be a significant benefit to our airline customers in terms of fuel savings.”

“Slowing aircraft down during the en-route phase of flight when they are much higher will save fuel and CO2emissions, while reducing the impact of noise for those living under the holding stacks in the south east of England.”

Maurice Georges, DSNA chief executive officer, added: “I am pleased with this collaboration between NATS and DSNA on this ambitious project in the FABEC development. Our operational teams are very enthusiastic.”

Gerald Regniaud, Project Leader for Reims Area Control Centre, explained: “A dedicated HMI has been specifically developed to display London-Heathrow Arrival Management Information directly at the Control Working Position. Thus, from 350Nm out of the runway, when aircraft are still at cruising level, they will have their speed controlled in order to absorb up to 3 minutes of delay”.

The trial, which is a partnership between members of FABEC and the UK/Ireland FAB, will run until the end of 2014.
An AirportWatch member commented:
It appears that the  XMAN trial is having benefits in reducing holding which will have its effect on 3Di.  People in some parts of west London are not noticing anything like the number of de-alternated planes using the wrong, mixed-mode runway.  This means that people have the impression that respite is working better, and people are not being annoyed by planes landing on the “wrong” runway, disturbing their quiet period.
Another bit of good news was hidden in

“…a decision has been taken at the Heathrow Noise and Air Quality Steering Group to remove the Phase 2 of the Departure Enhancement Project Heathrow Easterly Package (HEP). This means that there will be no trial of a Detling RNAV SID, which intended to replicate a track similar to Operational Freedom.”

Bits of south-west London may breathe more happily. The grounds for the change in plan are not given. Was it thought that there were no great benefits ? Or was Heathrow worried that another Warnham-type furore in Wimbledon and Wandsworth would occur at the wrong time for the next phase of the Airports Commission work ? Still a new concentrated straight-line Dover/Detling RNAV route will be tried for westerly departures – but it will be higher and routed a bit further away from Central London and may have less impact.



Ian Jopson, of NATS, explains their new technology to reduce aircraft emissions at landing and take off

4.4.2013NATS, the body that deals with UK air traffic control, has been attempting to reduce aircraft fuel consumption and carbon emissions by getting planes to take more direct routes, and land and take off at a continuous rate. They have devised a programme they call Flight Profile Monitor, which helps them achieve this. It uses radar data to monitor the 3 dimensional flight profiles of individual aircraft and to then record which of those were achieving smooth, continuous climbs and descents. Ian Jopson from NATS claims that from a 12 month trial last year between NATS, BMi, BMi Regional, Loganair, easyJet, Ryanair and Edinburgh Airport they achieved a saving of “at least 800 tonnes of CO2 and 250 tonnes of fuel” (tiny in comparison with the UK total). This was done by analysing each flight to see where savings could be made. They got a 20% increase in continuous descent landings, to around 55%. They also got around 95% with a continuous climb rate.  NATS hopes to get more savings in future.





NATS meets its target in 2012 to organise UK airspace to save planes wasting fuel

Edit this entry.NATS – which provides air traffic navigation services for the UK – says it has met its target for 2012, in terms of organising airspace to minimise the amount of fuel burnt by aircraft, and hence their CO2 emissions.  Its scheme, called 3Di, aims to keep planes flying optimally in terms of both their height, the amount of level flight, and the distance they have to travel.  The ideal is for planes to land directly, on a straight line, coming down by continuous descent approach.  With the airspace over much of the  UK being some of the most crowded in the world, such an ideal is not always possible. Each flight gets a 3Di score, and then NATS gets a total score for the year.   If NATS meets a 3Di score each year of 24, it meets its requirements. If the score is over 27, it gets penalised.  If below 21, NATS gets bonuses. In 2012 its score was 23.9.

NATS has data on its first 6 months of new flight efficiency metric, 3Di

3.8.2012NATS has released data from the first 6 months of operation of its new metric to reduce aircraft emissions of planes in UK airspace, through improved efficiency of airspace management and flight path directness.  The metric is called 3Di.  Flights are given a score depending on how fuel efficient their course has been, by continuous climb departures, cruise levels as requested by airspace users and continuous descents, as well as most direct point-to-point routeings – ie. horizontal and vertical line.  NATS claims the 3Di tool will give huge fuel savings, it ” is designed to deliver 600,000 tonnes of CO2 savings over the next 3 years – the equivalent to 10,000 flights from London to New York.” The challenge for NATS is sorting out direct flight paths with a high volume of flights and limited runway capacity (at some times of day) at Heathrow, as well as bad weather.