4

The approach plate specifies that "DME" is required for this approach (see the upper left of the approach plate). The FAA Instrument Flying Handbook (page 9-27) specifies that the GPS database must be "current" if the GPS is to be substituted for DME. GPS Substitution for ADF or DME Using GPS as a substitute for ADF or DME is subject to ...


3

The simplest answer is that non-precision approaches (e.g. LOC or VOR) nearly always have higher minima than precision approaches (e.g. ILS). Precision approaches provide strict vertical guidance: the pilot flies a constant descent angle down a precise glide slope/path, and if they don’t see the runway by the time they reach the DA, they immediately climb ...


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