Can a deployable ILS operate in CAT II or CAT III? As far as I know a deployable ILS can operate only in CAT I.


1 Answer 1


This article only states Cat 1. Deployable ILS project has been ongoing for 7+ years, so -1 to you for not posting anything relevant about it in your question.

The D-ILS is to provide a system of equal performance to existing Category I fixed-based systems that provide aircraft guidance on final approach in low-visibility and low-ceiling weather conditions.


March 2010 article on expected May 2010 Request For Proposal release:

The final RFP is anticipated to be out in May with source selection in June, and an award by December. Initial operational capability is scheduled to occur in early 2013.


Here is another that says it is available in a transportable configuration and says it can do Cat II. Is it available? I don't know, the AF seems to be buying the Thales version currently.

Transportable and permanent configurations

Meets icao cat II ILS specifications

For Ground Controlled Approach (gca) operations, the ILS provides controllers with par-like displays for up to four aircraft. All ILS glide slope and localizer signal parameters comply with icao Annex 10 standards for Category II ils, including accuracy, integrity, displacement sensitivity, clearance, alignment, modulation and frequency. The fixed-based ILS has been approved by the faa for use in the National Airspace System.


  • $\begingroup$ Thanks, the ILS CAT definiton is linked non only to the electronic part but to the overall integrated system (including antennas, cabling,) as is linked to the probability of a critical failure during the landing final phase. In case of a deployable ILS system( antennas not fixed to a concrete basement and stabilized and bracing, RF cables not located in cableducts, the probability of a failure is higher than for a fixed installation and that's why a deployable ILS is only for CAT I. What i can't find is any doc, advisory, rules issued by a regulatory body (ICAO, FAA,..) about. $\endgroup$ Nov 20, 2018 at 11:20
  • $\begingroup$ @massimosanvito: I believe what you're looking for is § and next of Annex 10 to the Convention (here for LLZ). $\endgroup$
    – mins
    Nov 21, 2018 at 21:01

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