Aviation Maintenance Terms beginning with P

P-S

Parallel to Series

PA

Passenger Address; Power Amplifier

PARA/SER

Parallel to Serial

PCB

Plenum chamber burning. A method of thrust augmentation used on engines with vectored nozzles. Fuel injected into the fan-discharge air is burned to increase thrust.

PCU

Passenger Control Unit; Power Control Unit

PFD

Permanentmagnet Generator

PMA

Parts manufacturer approval.

PNP transistor

A bipolar transistor made of a thin base of N-type silicon or germanium sandwiched between a collector and an emitter, both of which are made of P-type material.

POA

Position Offset Applied

POC

Portable oxygen concentrator.

POH

Pilot’s Operating Handbook. A document published by the airframe manufacturer and approved by the FAA that lists the operating conditions for a particular model of aircraft. Engine operating parameters are included in the POH.

POS

Positive

POT

Potentiometer; Plan Of Test

PR

Power Relay

PRL

Parallel

PROM

Programmable Read-Only Memory

PROX

Proximity

PRT

Power recovery turbine. A turbine driven by exhaust gases from several cylinders of a reciprocating engine. Energy extracted from exhaust gases by the turbine is coupled, through a fluid clutch, to the engine crankshaft.

PSEU

Proximity Switch Electronic Unit

PSI

Pounds Per Square Inch

PTFE Tape (Insulation)

Polytetrafluoroethylene tape. (commonly known by the trade name, Teflon™), wrapped around a conductor and then centered with heat, fusing the layers into a virtually homogeneous mass. It is used both as a primary insulation against the conductor, and as an outer layer or jacket over a shield. Maximum temperature rating is 260 °C.

PV diagram

A diagram showing the relationship between the volume of a cylinder and the pressure during a cycle of engine operation.

PVC (Polyvinylchloride)

A thermoplastic resin used to make transparent tubing for insulating electrical wires.

PVF2

Polyvinylidine Fluoride. A fluorocarbon plastic, that when used in aircraft wire, is invariably radiation cross-linked and employed as the outer layer.

PWR

Power

PWR SPLY

Power Supply