P-RNAV NND-1/Precision.Area.Navigation Protocol A.set.of.rules.for.the.format.and.content.of.
messages.between.communicating.processes.
PROV Provisional
PROX Proximity
PRSOV Pressure.Regulating.and.Shutoff.Valve
P/RST Press.To.Reset
PRTR Printer
PS Power.Supply
PSA (.1.).Power.Supply.Assembly..
(.2.).Preselect.Altitude
PSAA Product.Support.&.Assurance.Agreement
PSAS Primary.Stability.Augmentation.System
PSCP Project Specific Certification Plans
PSCU Programmable.System.Control.Unit
PSD Port.Sharing.Device
PSDN Packet.Switched.Data.Network
PSE Power Supply Equipment
PSEU Proximity.Sensor.Electronic.Unit
PSID Pounds per square inch Differential
PSIG Pounds per square inch Gage
PSL/PSA Problem.Statement.Language/Problem.Statement.
Analyzer PSM (.1.).Power.Supply.Modules..
(.2.).Product.Support.Managers
PSN Packet.Switching.Network
PSP Partnership.for.Safety.Plan
PSPL Preferred.Standard.Parts.List
PSR Primary.Surveillance.Radar..The.part.of.the.ATC.
system.that.determines.the.range.and.azimuth.of. an.aircraft.in.a.controlled.air.space.
PSS Proximity.Sensor.System
PSSA Preliminary.System.Safety.Assessment

PSU  Passenger.Service.Unit 
PT  Total.Pressure 
PTR  Production Test Requirements 
PTCH  Pitch:.Movement.about.the.lateral.(left.to.right). 
axis.of.the.aircraft. 
PTD  Performance.Test.Domain 
PSE  Packet.Switching.Exchange 
PSTN  Public.Switched.Telephone.Network 
PTH  Path 
PTI  Packet Type Identifier 
PTM  Peripheral Transition Module (I/O interface for 
SBC) 
PTR  Production Test Requirements 
PTS  Problem.Tracking.System 
PTSD  Production Test Specification Document 
PTT  (.1.).Post,.Telephone.and.Telegraph.. 
(.2.).Push.To.Talk..Also.refers.to.the.switching. 
signal.that.enables.the.transmitter... 
(.3.).Push.To.Test 
PTU  Power.Transfer.Unit 
PVD  Plan.View.Display 
PV  Parameter.Value 
PVC  Permanent.Virtual.Circuit 
PVT  Position,.Velocity,.Time 
PWB  Printed.Wire.Boards 
PWM  Pulse-Width.Modulation