While researching where Heathrow's MLS approachs had gone, the only thing I could find is a topic on Heathrow's new eILS (enhanced ILS). As of the topic's date (Aug 2015) it seems eILS is only available in Heathrow and Zurich (at least for Europe).

While researching what eILS is (was not easy), I found this IATA presentation from 2017 that discusses it. It mentions the following:

Ability to handle multiple A380s in Wide Area of the DLSA (currently only 1) and retain ILS usage, as no DLSA.

And it shows a diagram that I don't really understand:

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I tried to search for ILS DLSA (Dynamic Localiser Sensitive Area), but I couldn't find anything. So, how does eILS do its thing?

  • $\begingroup$ What do you mean with: "How does eILS does its thing" ? I can acces the technical documentation of the systems used at Heathrow and Zurich. Is the question more towards, how does this eILS reduce the separation between aircraft and thus increase capacity during CAT III landings? Or more in the techinical field, as how does the transmitted wave look like? Angles, size etc.? $\endgroup$ – Brilsmurfffje Apr 14 '19 at 21:17
  • $\begingroup$ @Brilsmurfffje: The title question, which would ideally explain the difference (the how). $\endgroup$ – ymb1 Apr 14 '19 at 22:53

The bigger the aircraft, the more disturbance it creates to the ILS signal while moving on the runway (or TWY). Therefore airports have static and dynamic ILS sensitive areas to assure the validity of ILS signal. The eILS has smaller dynamic localizer sensitive areas, and aircraft (A380 in this case) will vacate this area in less time, enabling reduced separation and increasing throughput.

A little something about ILS critical and sensitive areas: Determination of ILS Critical and Sensitive Areas - icasc (.pps)

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