Is the ILS CAT III the most technologically sophisticated navigation / landing system available for helping commercial pilots land a commercial passenger aircraft in severe and extremely low visibility weather conditions. Does the airport require special compatible equipment for this system to work properly?

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    $\begingroup$ Please clarify what you mean by "auto landing". No aircraft can land fully automatically since, brakes, spoilers, flaps and gear cannot be operated by the auto pilot. $\endgroup$
    – Simon
    Sep 28, 2015 at 20:51
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    $\begingroup$ @Simon, I beg to differ, the autopilot I helped design and has been tested in flight 3 weeks ago, can :P $\endgroup$
    – Federico
    Sep 28, 2015 at 21:09
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    $\begingroup$ Your question is a little unclear (what does "sophisticated" mean?) but there are many questions on this site about autoland, ILS and so on. I suggest you review them first and then edit your question to be more precise. This one might be a good start, then this one. $\endgroup$
    – Pondlife
    Sep 28, 2015 at 21:41
  • $\begingroup$ @FLIGHTWARS the spoilers and auto brakes must be manually armed. They are not armed by the autopilot (although Federico has built one that does). $\endgroup$
    – Simon
    Sep 29, 2015 at 10:20
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    $\begingroup$ @simon Well, the autopilot has to be setup for the approach and landing too, so arming those systems isn't really much different, especially since the question asks about the auto land system, and not the auto pilot... $\endgroup$
    – Lnafziger
    Sep 29, 2015 at 13:10

2 Answers 2


Yes ILS equipment for CATIII is the most sophisticated across ILS systems. As people mentioned in comments there are another types of landing systems, which could be more complex. No it is not auto landing system.

It self CATIII is a category of a landing conditions.

Also take a look here What is different between a Cat IIIA, Cat IIIB, and Cat IIIC ILS approach?

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    $\begingroup$ ILS creates a straight path for landing. Autoland is a mechanism that follows this path, including managing the flare. Cat III ILS are certified for a better precision and accuracy (as well as protection from interference). However MLS and GPS (GNSS) are far more complex. $\endgroup$
    – mins
    Sep 29, 2015 at 8:17
  • $\begingroup$ Thx for links! Edit my answer. $\endgroup$
    – Jeka
    Sep 29, 2015 at 8:31
  • $\begingroup$ The question asks if it is the most sophisticated landing system available, not if it is the most sophisticated ILS. :) $\endgroup$
    – Lnafziger
    Sep 29, 2015 at 13:12

ILS Category 3C is true 'autoland' with no limitation regarding Decision Height for landing or Runway Visual Range. It's not especially complex (the equipment is not technically challenging)but has specific requirements regarding the equipment fitment for Cat 3C.

MWLS/MLS (microwave landing system) was researched which had some advantages including lifting the need to approach in a straight line. Although truly more complex than ILS, ther advantages it offered were not considered sufficiently worthwhile to proceed. https://en.wikipedia.org/wiki/Microwave_landing_system

Today, the most complex 'landing system' is probably those based on GPS(GNSS). Several (smaller) countries have announced their intention to replace ILS provision with precision GPS or LPV approaches. This requires greater accuracy than unaugmented GPS can provide and this is achieved using Differential GPS and Wide Area Augmentation System. https://en.wikipedia.org/wiki/Differential_GPS https://en.wikipedia.org/wiki/Wide_Area_Augmentation_System

The result is the LPV approach. https://en.wikipedia.org/wiki/Localizer_performance_with_vertical_guidance

This is currently the most complex 'autoland' from a technical standpoint but still has DH/DA and RVR limitations, thus making it less 'complete' than ILS Cat 3C. It does not meet the ICAO Annex 10 precision approach standard.



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