background image

12/2/21 

Pilot/Controller Glossary 

PRECIPITATION

 Any or all forms of water 

particles (rain, sleet, hail, or snow) that fall from the 
atmosphere and reach the surface. 

PRECIPITATION RADAR WEATHER DESCRIP-
TIONS

 Existing radar systems cannot detect 

turbulence. However, there is a direct correlation 
between the degree of turbulence and other weather 
features associated with thunderstorms and the 
weather radar precipitation intensity. Controllers will 
issue (where capable) precipitation intensity as 
observed by radar when using weather and radar 
processor (WARP) or NAS ground

based digital 

radars with weather capabilities. When precipitation 
intensity information is not available, the intensity 
will be described as UNKNOWN. When intensity 
levels can be determined, they shall be described as: 

a. 

LIGHT (< 26 dBZ) 

b. 

MODERATE (26 to 40 dBZ) 

c. 

HEAVY (> 40 to 50 dBZ) 

d. 

EXTREME (> 50 dBZ) 

(Refer to AC 00

45, Aviation Weather Services.) 

PRECISION APPROACH

 

(See PRECISION APPROACH PROCEDURE.) 

PRECISION APPROACH PROCEDURE

 A 

standard instrument approach procedure in which an 
electronic glideslope or other type of glidepath is 
provided; e.g., ILS, PAR, and GLS. 

(See INSTRUMENT LANDING SYSTEM.) 

(See PRECISION APPROACH RADAR.) 

PRECISION APPROACH RADAR

 Radar equip-

ment in some ATC facilities operated by the FAA 
and/or the military services at joint-use civil/military 
locations and separate military installations to detect 
and display azimuth, elevation, and range of aircraft 
on the final approach course to a runway. This 
equipment may be used to monitor certain non

radar 

approaches, but is primarily used to conduct a 
precision instrument approach (PAR) wherein the 
controller issues guidance instructions to the pilot 
based on the aircraft’s position in relation to the final 
approach course (azimuth), the glidepath (elevation), 

and the distance (range) from the touchdown point on 
the runway as displayed on the radar scope. 

Note: The abbreviation “PAR” is also used to 

denote preferential arrival routes in ARTCC 
computers. 

(See GLIDEPATH.) 
(See PAR.) 
(See PREFERENTIAL ROUTES.) 
(See ICAO term PRECISION APPROACH 

RADAR.) 

(Refer to AIM.) 

PRECISION APPROACH RADAR [ICAO]

 Pri-

mary radar equipment used to determine the position 
of an aircraft during final approach, in terms of lateral 
and vertical deviations relative to a nominal approach 
path, and in range relative to touchdown. 

Note: Precision approach radars are designed to 

enable pilots of aircraft to be given guidance by 
radio communication during the final stages of the 
approach to land. 

PRECISION OBSTACLE FREE ZONE (POFZ)

 

An 800 foot wide by 200 foot long area centered on 
the runway centerline adjacent to the threshold 
designed to protect aircraft flying precision 
approaches from ground vehicles and other aircraft 
when ceiling is less than 250 feet or visibility is less 
than 3/4 statute mile (or runway visual range below 
4,000 feet.) 

PRECISION RUNWAY MONITOR (PRM) 
SYSTEM

 Provides air traffic controllers 

monitoring the NTZ during simultaneous close 
parallel PRM approaches with precision, high update 
rate secondary surveillance data. The high update rate 
surveillance sensor component of the PRM system is 
only required for specific runway or approach course 
separation. The high resolution color monitoring 
display, Final Monitor Aid (FMA) of the PRM 
system, or other FMA with the same capability, 
presents NTZ surveillance track data to controllers 
along with detailed maps depicting approaches and 
no transgression zone and is required for all 
simultaneous close parallel PRM NTZ monitoring 
operations. 

(Refer to AIM) 

PREDICTIVE WIND SHEAR ALERT SYSTEM 
(PWS)

 A self

contained system used on board some 

aircraft to alert the flight crew to the presence of a 
potential wind shear. PWS systems typically monitor 
3 miles ahead and 25 degrees left and right of the 

PCG P