R-C&W Rack.Connectors.and.Wiring RCAG Remote.Center.Air/Ground.Station RCC Remote.Charge.Converter RCE Radio Control Equipment RCFD Rockwell.Collins.Flight.Dynamics RCL (.1.).Radio.Communications.Link..
(.2.).Recall
RCO Remote Communications Outlet RC-MAP Rockwell.Collins.Management.Authorization. Process RCP (.1.).Radio.Control.Panel.
( 2 ) Required Communications Performance
RCR Routing.and.Circuit.Restoral RC-TCP Rockwell.Collins.Technical.Consistent.Process RCU Remote.Control.Unit RCVR Receiver R&D Research.and.Development Rd R-Channel.used.for.data RDARA Regional.Domestic.Air.Route.Area RDC (.1.).Routing.Domain.Confederation..
(.2.).Remote.Data.Concentrator RDF Routing.Domain.Format RDI Routing Domain Identifier RDMI Radio.Distance.Magnetic.Indicator RDP Radar.Data.Processing.(system) RDR Radar RDSS Radio.Determination.Satellite.Service RDU (.1.).Receiver/Decoder.Unit..
(.2.).Remote.Display.Unit
RDV Requirements Development and Validation RDVS Rapid.Deployment.Voice.Switch RECAP Reliability.Evaluation.and.Corrective.Action.
Program

REF  Reference 
REFL  Reflection 
Reflectivity Factor (Z)  This.is.a.measurement.of.the.ability.of.a.target.to. reflect the energy from a radar beam. 
Relative Bearing  The.bearing.of.a.ground.station.relative.to.the. direct.ion.the.aircraft.nose.points,.or.the.direction. of.an.aircraft.to.or.from.an.NDB. 
REL  Relative 
Remote  A.probability.of.occurrence.greater.than.1.x.10^-7 but less than or equal to 1 x 10^-5 per hour of flight, or per event (e.g. takeoff, landing) 
REP  Reliability.Enhancement.Program 
REQ  ( 1 ) Request . ( 2 ) Required/Requirement 
RER  Residual.Error.Rate 
Resolution Advisory  A.display.indication.given.to.the.pilot. recommending.a.maneuver.to.increase.vertical. separation.relative.to.an.intruding.aircraft..A. resolution advisory is also classified as corrective or.preventive. 
RESTR  Restriction 
RESYNCING  Resynchronizing 
RET  (.1.).Rapid.Exit.Taxiway.. (.2.).Reliability.Evaluation.Test 
REU  Remote.Electronics.Unit