Info to our Operators
In response to a request from 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 May 13th and will 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 Due to delays in publication, the AIC for this trial will not be published until the 19th June 2008.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, we were keen to start the trial before this date to avoid delaying the benefits - Hence the procedure has been implemented tactically as from May 13th.
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.
During normal operations for inbound flights into the LTMA, ATC may instruct pilots to fly a designated indicated airspeed from the top of descent. 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.
NATS welcomes your feedback regarding this trial.
For more info:
NATS Corporate and Technical Centre (CTC)
4000 Parkway
Whiteley
Hampshire
PO15 7FL