What determines whether DME is provided by the ILS?

The provision of Distance Measuring Equipment (DME) in relation to an Instrument Landing System (ILS) approach is primarily determined by the specific instrument approach procedure published on the approach chart, which can be described as plate dependent. This means that when reviewing a particular ILS approach plate, it will indicate whether DME is part of that approach.

Different ILS approaches may have specific requirements regarding the use of DME, and these requirements will be explicitly stated on the approach chart. This differentiation allows pilots and air traffic control to know whether DME guidance is available or required for a particular approach, making it essential for adherence to the published procedure.

Other options, such as aircraft capabilities, pilot requests, and air traffic control instructions, may have roles in the overall context of flight operations and navigation, but they do not dictate the presence or absence of DME for a specific ILS approach. The approach plate outlines these requirements, ensuring that pilots have reliable and consistent information regarding the navigation aids available during the approach.