Final answer:
When the elevation portion of PAR equipment fails during a precision approach, a pilot must initiate a missed approach procedure, as continuing the approach without complete guidance is unsafe.
Step-by-step explanation:
If the elevation portion of PAR equipment fails during a precision approach, the correct action to take is to initiate a missed approach procedure. Precision Approach Radar (PAR) is established to provide both lateral and vertical guidance to an aircraft on approach for landing. Loss of the vertical guidance would compromise the safety and precision required for such an approach. Therefore, it is essential to discontinue the approach when this critical element can no longer be provided. Continuing without vertical guidance or switching to another navigation system might not offer the required precision, and descending without proper reference could be dangerous.
The pilot in command should always follow the established missed approach or go-around procedures, immediately climbing to a specified altitude and following the missed approach instructions as dictated by the air traffic control (ATC) or the published procedure for the airport.