Which altitude minimum applies when conducting a procedure with DME for a step-down fix?

When conducting a procedure with Distance Measuring Equipment (DME) for a step-down fix, the minimum altitude decreases. This is because the use of DME allows pilots to accurately determine their distance from the fix, thus enabling a more precise approach and the ability to safely descend to lower altitudes before reaching that fix.

The step-down fix represents a point in the approach where a pilot is permitted to descend to a lower altitude, provided they maintain the required visibility and are aware of the terrain and obstacle clearance in the area. The DME aids in ensuring that the aircraft is at a safe distance from lower altitudes in relation to ground features, which is essential for safe navigation during an instrument approach.

In this context, altitude restrictions can be more precise, and thus, the presence of DME typically allows pilots to operate at lower altitudes safely as they approach the fix. This carefully controlled descent creates opportunities for improved efficiency during an approach, adhering to safety protocols regarding obstacle clearance.