Definition
An instrument approach conducted to one of two closely spaced parallel runways where a dedicated final monitor controller, using high-update precision radar and specific PRM procedures, watches the aircraft's track to ensure it does not stray toward the parallel approach course. Pilots must be PRM-qualified, monitor a second tower frequency, and be prepared to fly an immediate breakout if instructed.
Plain English
A parallel runway approach where a separate controller watches your radar track closely the whole way down, in case you drift toward the airplane landing on the runway right next to you. You listen on two radios and must be ready to break off the approach instantly if told.
Context Anchor
Seen on instrument approach charts and in air traffic control clearances at airports that use simultaneous approaches to parallel runways.
Derivation
PRM stands for Precision Runway Monitor. 'Precision' refers to the high-resolution, fast-updating radar used; 'monitor' reflects the controller's role of watching rather than directing the approach.
Why Pilots Care
Allows safe use of closely spaced parallel runways that would otherwise require greater separation, increasing airport capacity while maintaining collision avoidance through real-time monitoring and breakout instructions.
Intuition Check
Monitoring does not mean only that the pilot is watching the instruments. In this term, air traffic control is actively watching aircraft paths and may issue urgent instructions to keep aircraft safely separated.
Example Sentence 1
Approach assigned us the ILS PRM 28L and reminded us to keep the tower monitor frequency selected on COM2.
Example Sentence 2
During the monitoring PRM approach the controller directed an immediate left turn due to a deviation on the parallel runway.