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Is MM necessary equipment for ILS CAT I operation?

Asked by: 605 views ,
Aircraft Systems, General Aviation

Hello  instructors,

I have a question about the ILS CAT I operation. A pilot told me the MM was not a necessary equipment for ILS CAT I including the replace fix, which usually is a DME distance from GP. But I can not find any regulation about it. Could you provide some informations about it?  

1)If the MM and its replaced DME fix were all inoperative, can we dispatch the flight with ILS CAT I minimums?

2)If the OM and its DME fix were all inop, can we dispatch the flight with ILS CAT I minimums?

Thanks a lot for your help.

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1 Answers

  1. Best Answer


    John D Collins on Dec 31, 2016

    The FAF fix is not a required part of the full ILS procedure because the interception of the GS does not require or use a FAF. The FAF is for the localizer option. There may be other requirements for DME on the approach, for example as part of the route that joins the approach, or the IAF, step downs in the intermediated segment, or the missed approach procedure. If one is equipped with a suitable RNAV system, they may substitute for the DME and to identify the location of these fixes. So if DME is required for the approach, it will be stated on the procedure and one will need a DME or suitable substitution. But since the FAF does not need to be identified on an ILS, it is not needed for that purpose.

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