Definition
An instrument approach procedure flown to one of two or more closely spaced parallel runways where simultaneous independent approaches are conducted. PRM approaches require high-update-rate surveillance, special controller monitoring on a dedicated frequency, and specific pilot training and procedures to ensure safe separation between aircraft on adjacent final approach courses.
Plain English
An approach to a runway that has another runway right next to it, where two planes can land at the same time on parallel paths. Because the runways are close together, controllers watch each aircraft very carefully on a special radar and a separate radio frequency, ready to direct one aircraft to break off if the other drifts toward it.
Context Anchor
Seen on approach charts, in ATC clearances, and during arrivals to larger airports with closely spaced parallel runways.
Derivation
PRM stands for Precision Runway Monitor. 'Precision' here refers to the high accuracy of the radar used to track aircraft positions, and 'monitor' reflects the dedicated controller watching each approach to catch any deviation quickly.
Why Pilots Care
Allows higher arrival rates at airports with closely spaced parallel runways while preserving required safety margins.
Intuition Check
Do not read “PRM Approach” as simply a more accurate approach. The key idea is that the approach is specially monitored because aircraft may be flying close, parallel arrival paths at the same time.
Example Sentence 1
Before accepting the ILS PRM approach into runway 28R, the crew reviewed the breakout procedure and tuned the monitor frequency on the second radio.
Example Sentence 2
PRM Approach procedures require the pilot to monitor the frequency for breakout instructions if separation is lost.