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Old 13th Oct 2014, 15:38
  #18 (permalink)  
Elephant and Castle
Join Date: Apr 2008
Location: Up high
Posts: 555
The ILS RWY 08 approach into CYBR I think is a good example of the approach that you are asking about.
you may use another nav source to navigate... which seems quite obvious in this case since the ILS only works when lined up on the final approach course!
I cannot say that I agree. At least where I am we are not allowed to fly below the MSA unless under radar control or visual with the ground or flying an approved instrument procedure. The OP said there was no radar so the only way to fly the approach , starting at the dme arc, is either if you are visual or you just keep above the msa (4300 in your plate) and then intercept the localiser at that altitude and descend with the GS. A RNAV approach would specify the required navigation (GNSS, IRS...) and might also specify a minimum temperature. An RNAV approach also has specific procedures in case of a nav accuracy downgrade. You cannot invent a RNAV appoach out of a normal approach just because one of the aids is not working.

All an overlay apprach does is allow the FMS to guide the airplane while you check it complies with the raw data. You cannot fly an overlay approach if the raw data is missing. In that case what you need is a RNAV approach and that is a slightly different animal for the reasons mentioned.

The only reason your plate does not say ILS DME is because arriving from the west you dont need the DME. That does not mean that you can fly a DME arc below the MSA without the DME.
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