PROX PROXIMITY
PRSOV PRESSURE RAISING AND SHUTOFF VALVE
PRTR PRINTER
PRV PRESSURE REGULATOR VALVE
PS POWER SECTION
PS PUMP SUPPLY PRESSURE
PSB BEARING PRESSURE
PSC PRE SET COURSE
PSCU PROXIMITY SWITCH CONTROL UNIT
PSH PRE SET HEADING
PSI POUNDS PER SQUARE INCH (14.5 PSI = 1 BAR)
PSIA POUNDS PER SQUARE INCH ABSOLUTE
PSID POUNDS PER SQUARE INCH DIFFERENTIAL
PSIG POUNDS PER SQUARE INCH GAUGE
PSIU PASSENGER SERVICE AND INFORMATION UNIT
PSNSRF PRESSURE SENSOR FAILURE
PSR PRIMARY SURVEILLANCE RADAR
PSRM POWER PLANT STRUCTURAL REPAIR MANUAL
PSS PASSENGER SERVICE SYSTEM
PSS PRESSURE SUB SYSTEM (ECU)
PSU PASSENGER SERVICE UNIT
PSW PRESSURE SWITCH
PT POINT
PT TOTAL AIR PRESSURE
PTC POSITIVE TEMPERATURE COEFFICIENT
PTCH PITCH ANGLE
PTCR BODY AXIS PITCH RATE
PTFE TEFLON
PTP PROGRAMMING AND TEST PANEL
PTR PRINTER
PTT PUSH TO TALK
PTU POWER TRANSFER UNIT (HYDRAULIC)
PU POWER UNIT
PUT POWER UP TEST
PW PRATT AND WHITNEY
PWA PRINTED WIRING ASSEMBLY
PWM PULSE WIDTH MODULATOR
PWR SPLY POWER SUPPLY
PWR POWER (ENGINE, ELECTRIC, HYDRAULIC, PNEUMATIC)
Q D QUICK DONNING
Q QUEBEC
QAD RING QUICK ATTACH DETACH RING
QAD QUICK ATTACH DETACH
QAR QUICK ACCESS RECORDER
QDM MAGNETIC DIRECTION TO STATION
QDR TRUE DIRECTION FROM STATION
QEC QUICK ENGINE CHANGE
QFE FIELD ELEVATION ATMOSPHERE PRESSURE
QFF RUNWAY HEADING
QFU RUNWAY HEADING
QNE SEA LEVEL STANDARD ATMOSPHERE PRESSURE (1013.25 HPA)
QNH SEA LEVEL ATMOSPHERE PRESSURE
QTE TRUE DIRECTION TO STATION
QTY QUANTITY
QUJ MAGNETIC DIRECTION FROM STATION
R ROMEO
R / A RADIO ALTIMETER, RADIO ALTITUDE, RADIO HEIGHT
Aircraft Systems - Abbreviations and Acronyms 41

R / D REFUEL / DEFUEL
R / H RIGHT HAND
R / I RADIO / INERTIAL
R / I REMOVAL / INSTALLATION
R / L READING LIGHT
R RED
R REVISED (PAGES)
R RIGHT
RA RADIO ALTIMETER, RADIO ALTITUDE, RADIO HEIGHT
RA RESOLUTION ADVISORY (TCAS)
RAC / SB ROTOR ACTIVE CLEARANCE / START BLEED
RAC ROTOR ACTIVE CLEARANCE
RACC ROTOR ACTIVE CLEARANCE CONTROL
RACCS ROTOR ACTIVE CLEARANCE CONTROL SYSTEM