Definition
A high-resolution color radar display used by the final monitor controller during simultaneous parallel ILS approaches. It shows aircraft position relative to the final approach courses and the No Transgression Zone (NTZ) between them, and provides automated alerts when an aircraft is predicted to or has deviated toward the adjacent approach course.
Plain English
A specialized radar screen that air traffic controllers use to watch aircraft flying side-by-side approaches into parallel runways, making sure none of them stray toward the other aircraft's path.
Context Anchor
Seen in discussions of Precision Runway Monitor approaches, especially at airports using closely spaced parallel runways.
Derivation
Monitor' comes from the Latin monere, meaning 'to warn.' The display's purpose is exactly that — to warn the controller (and through them, the pilot) when an aircraft is drifting into unsafe territory.
Why Pilots Care
It allows controllers to detect and correct course or altitude deviations quickly, reducing the chance of an unstabilized approach or runway incursion.
Intuition Check
Do not read Final Monitor Aid as a general helpful procedure or a person watching final approach. In FAA use, it means a specific controller display and alerting tool used for monitoring parallel approaches.
Example Sentence 1
During simultaneous ILS approaches to runways 28L and 28R, the final monitor controller watched the Final Monitor Aid for any deviation toward the No Transgression Zone.
Example Sentence 2
During the ILS approach in low visibility, the final monitor aid confirmed the aircraft was staying on the glide slope.