R/C Radio control
R&D Research and development
R&M Reliability and maintainability
R/Nav re: RNAV
RAAWS Radar altimeter & altitude warning system
radar Radio detection and ranging
radius of action Maximum distance a (combat) aircraft can fly with a normal load and return to base without (inflight) refuelling
RAeS Royal Aeronautical Society (UK)
RAF Royal Air Force (UK)
RAFVR Royal Air Force Volunteer Reserve (UK)
RAI Registro Aeronautico Italiano; Italian civil aviation authority
RAM Radar absorbent material
also:   Random access memory
ramp weight MTOGW plus fuel allowances for taxi & run-up
RAP Rocket assisted projectile
RAS Rectified airspeed; IAS corrected for position error
RAT Ram air turbine
RATO Rocket assisted take-off
RATOG Rocket assisted take-off gear
RAuxAF Royal Auxiliary Air Force
RAWS Radar altitude warning system
also:   Radar attack and warning system
RCC Rescue co-ordination centre
RCS Radar cross section
RDT&E Research, development, test and evaluation
reaction-control jet Nozzles on extremities of aircraft which, using engine bleed air, control the aircraft
redundancy Capability to continue function after failure of primary system
RESA Runway end safety area
revenue passengers Passengers who pay 25% or more of normal applicable fare
RF Radio frequency
RFID Radio frequency identification
RfP Request for proposal
RG Reconnaissance Group (USAF)
RHAW Radar homing and warning
RHWR Radar homing and warning receiver
RHWS Radar homing and warning system
RIC Reconnaissance interpretation centre
RIO Radar intercept officer
RMI Radio magnetic indicator
also:   Remote magnetic indicator
RNAV Navigation system which uses 'ghost' beacons in combination with airways beacons to calculate position with reference to any point on the surface
ROC or roc Rate of climb
root Innermost part of a wing where it attaches to the fuselage
RPA Remotely piloted airship
also:   Remotely piloted aircraft
rpg Rounds per gun
rpm Revolutions per minute
RPV Remotely piloted vehicle
RQF Rescue Flight (USAF)
RQS Rescue Squadron (USAF)
RQW Rescue Wing (USAF)
RRC Rapid Reaction Corps (NATO)
RRF Rapid Reaction Force (NATO)
RS Reconnaissance Squadron (USAF)
RSA Réseau du Sport de l'Air; French EAA
RSS Relaxed static stability
RTB Return to base
RTF Radiotelephone
ruddervator Moving flight control surface of V-tail; combines functions of rudder and elevator
RV Re-entry vehicle
RVR Runway visual range
RW Reconnaissance Wing (USAF)
RWR Radar warning receiver
RWS Radar warning system
RX Receiver
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