Definition
A ground-based radar approach in which a controller, watching a high-resolution radar display, gives the pilot continuous verbal guidance for both course (left/right of centerline) and glidepath (above/below the correct descent profile) all the way down to the runway. PAR provides precision vertical and lateral guidance and is treated as a precision approach for IFR alternate planning purposes.
Plain English
A type of instrument approach where a radar controller on the ground watches your aircraft on a special radar and talks you down to the runway, telling you how to stay on the correct path left/right and how to stay on the correct descent angle.
Context Anchor
Seen in instrument approach and IFR alternate planning discussions, especially when deciding what kinds of approaches are available at an airport.
Derivation
From 'precision' (exact, fine-grained) and 'approach radar' (radar used to guide aircraft on approach to landing). The 'precision' part signals that the radar gives both lateral and vertical guidance, unlike a surveillance approach which gives lateral only.
Why Pilots Care
When checking IFR alternate requirements, PAR counts as a precision approach. That affects which weather minimums apply when you list an airport as your alternate. Operationally, PAR is also a useful backup when an aircraft's onboard navigation equipment is degraded, since the guidance comes from the controller, not the airplane.
Intuition Check
PAR does not mean “par” as in average or normal performance. In instrument flying, PAR means Precision Approach Radar: a controller-guided radar approach to a runway.
Example Sentence 1
Because the destination forecast was marginal, the crew chose an alternate that had a published PAR approach to satisfy the precision approach requirement.
Example Sentence 2
IFR alternate planning sometimes accounts for airports equipped with PAR when standard instrument approaches are unavailable.