In response to a request from their airline customers, NATS is implementing an econ descent speed trial into the London TMA with the objective of reducing inner stack holding for the London airports.
This trial started on the 13th May and run for a period of 6 months. Due to delays in publication, the AIC for this trial will not be published until the 19th June 2008; however, they were keen to start the trial before this to avoid delaying the benefits. Hence the procedure has been implemented tactically from the 13th May 2008.
Modelling and simulations have indicated that approximately 1 minute of airborne holding can be avoided with an earlier and consistent application of econ descent speeds. By reducing the speed earlier, this procedure simply transfers part of the anticipated stack holding delay to the descent phase, thus reducing fuel burn and aviation related emissions. Total potential savings for LTMA arrivals are expected to exceed 12,000 tonnes of fuel per annum.
During normal operations for inbound flights into the LTMA, ATC may instruct pilots to fly a designated indicated airspeed in the descent of 270 knots within an 80-100nm radius. Level clearances as directed by ATC will not change and are mandatory. As is current standard operating practice, speed instructions to individual aircraft may be varied by ATC for the purposes of traffic separation and sequencing.
London TMA airfields are:
- Luton
- Biggin Hill
- Gatwick
- London City
- Heathrow
- Southend
- Cambridge
- Stansted
- Rochester
- Northolt
Feedback on the trial can be provided through the www.customer.nats.co.uk website.