## P TIME- 

(See PROPOSED DEPARTURE TIME.) 

## P-ACP- 

(See PREARRANGED COORDINATION PROCEDURES.) 

PAN-PAN- The international radio-telephony urgen- cy signal. When repeated three times, indicates uncertainty or alert followed by the nature of the urgency. 

(See MAYDAY.) 

(Refer to AIM.) 

## PAR- 

(See PRECISION APPROACH RADAR.) 

## PAR [ICAO]- 

(See ICAO Term PRECISION APPROACH RADAR.) 

PARALLEL ILS APPROACHES- Approaches to parallel runways by IFR aircraft which, when established inbound toward the airport on the adjacent final approach courses, are radar-separated by at least 2 miles. 

(See FINAL APPROACH COURSE.) 

(See SIMULTANEOUS ILS APPROACHES.) 

PARALLEL OFFSET ROUTE- A parallel track to the left or right of the designated or established airway/route. Normally associated with Area Navi- gation (RNAV) operations. 

(See AREA NAVIGATION.) 

PARALLEL RUNWAYS- Two or more runways at the same airport whose centerlines are parallel. In addition to runway number, parallel runways are designated as L (left) and R (right) or, if three parallel runways exist, L (left), C (center), and R (right). 

## PBCT- 

(See PROPOSED BOUNDARY CROSSING TIME.) 

## PBN- 

(See ICAO Term PERFORMANCE-BASED NAVIGATION.) 

## PDC- 

(See PRE-DEPARTURE CLEARANCE .) 

## P 

PERFORMANCE-BASED NAVIGATION (PBN) [ICAO]- Area navigation based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure or in a designated airspace. 

PERMANENT ECHO- Radar signals reflected from fixed objects on the earth's surface; e.g., buildings, towers, terrain. Permanent echoes are distinguished from “ground clutter” by being definable locations rather than large areas. Under certain conditions they may be used to check radar alignment. 

PHOTO RECONNAISSANCE- Military activity that requires locating individual photo targets and navigating to the targets at a preplanned angle and altitude. The activity normally requires a lateral route width of 16 NM and altitude range of 1,500 feet to 10,000 feet AGL. 

PILOT BRIEFING- A service provided by the FSS to assist pilots in flight planning. Briefing items may include weather information, NOTAMS, military activities, flow control information, and other items as requested. 

PILOT IN COMMAND- The pilot responsible for the operation and safety of an aircraft during flight time. 

PILOT WEATHER REPORT- A report of meteoro- logical phenomena encountered by aircraft in flight. (Refer to AIM.) 

PILOT'S DISCRETION- When used in conjunc- tion with altitude assignments, means that ATC has offered the pilot the option of starting climb or descent whenever he/she wishes and conducting the climb or descent at any rate he/she wishes. He/she may temporarily level off at any intermediate altitude. However, once he/she has vacated an altitude, he/she may not return to that altitude. 

Note: Performance requirements are expressed in navigation specifications (RNAV specification, RNP specification) in terms of accuracy, integrity, continuity, availability, and functionality needed for the proposed operation in the context of a particular airspace concept. 

(Refer to AIM.) 

(Refer to 14 CFR Part 91.) 

