Aeronautical Terms beginning with R
RA
Resolution Advisory,Radio Altitude
Rabbit, the
High-intensity flasher system installed at many large airports. The flashers consist of a series of brilliant blue-white bursts of light flashing in sequence along the approach lights, giving the effect of a ball of light traveling towards the runway.
Radar
Radio Detection And Ranging.
Radar altitude
The altitude of an aircraft determined by radar-type radio altimeter; thus the actual distance from the nearest terrain or water feature encompassed by the downward directed radar beam. For all practical purposes, it is the“actual” distance above a ground or inland water surface or the true altitude above an ocean surface.
Radar approach
The controller provides vectors while monitoring the progress of the flight with radar, guiding the pilot through the descent to the airport/heliport or to a specific runway.
Radar Required
A term displayed on charts and approach plates and included in FDC NOTAMs to alert pilots that segments of either an instrument approach procedure or a route are not navigable because of either the absence or unusability of a NAVAID. The pilot can expect to be provided radar navigational guidance while transiting segments labeled with this term.
Radar Route
A flight path or route over which an aircraft is vectored. Navigational guidance and altitude assignments are provided by ATC.
Radar Separation
Radar spacing of aircraft in accordance with established minima.
Radials
The courses oriented from a station.
Radio Beacon
Nondirectional Beacon.
Radio frequency (RF)
A term that refers to alternating current (AC) having characteristics such that, if the current is input to antenna, an electromagnetic (EM) field is generated suitable for wireless broadcasting and/or communications.
Radio magnetic indicator (RMI)
An electronic navigation instrument that combines a magnetic compass with an ADF or VOR. The card of the RMI acts as a gyro-stabilized magnetic compass, and shows the magnetic heading the aircraft is flying.
Radio or radar altimeter
An electronic altimeter that determines the height of an aircraft above the terrain by measuring the time needed for a pulse of radio-frequency energy to travel from the aircraft to the ground and return.
Radio wave
An electromagnetic wave (EM wave) with frequency characteristics useful for radio transmission.
RAIL
Runway Alignment Indicator Lights Sequenced Flashing Lights Which Are Installed Only In Combination With Other Light Systems
RAIM
Receiver Autonomous Integrity Monitoring.
Random RNAV routes
Direct routes, based on area navigation capability, between waypoints defined in terms of latitude/longitude coordinates, degree-distance fixes, or offsets from established routes/airways at a specified distance and direction.
Ranging signals
Transmitted from the GPS satellite, these allow the aircrafts receiver to determine range (distance) from each satellite.
RB
Relative Bearing.
RBI
Relative Bearing Indicator.
RCLS
Runway Centerline Light System.
RCO
Remote Communications Outlet.
RDOF
Radio Failure
Receiver autonomous integrity monitoring (RAIM).
A system used to verify the usability of the received GPS signals and warns the pilot of any malfunction in the navigation system. This system is required for IFR-certified GPS units.
Receiver-transmitter (RT)
A system that receives and transmits a signal and an indicator.
Recommended altitude
An altitude depicted on an instrument approach chart with the altitude value neither underscored nor overscored. The depicted value is an advisory value.
Reduced Vertical Separation Minimums (RVSM)
RVSM airspace is where air traffic control separates aircraft by a minimum of 1,000 feet vertically between flight level (FL) 290 and FL 410 inclusive. RVSM airspace is special qualification airspace; the operator and the aircraft used by the operator must be approved by the Administrator. Air traffic control notifies operators of RVSM by providing route planing information.
Reference circle (also, distance circle)
The circle depicted in the plan view of an IAP chart that typically has a 10 NM radius, within which chart the elements are drawn to scale.
Reference Landing Speed (Vref)
The speed of the airplane, in a specified landing configuration, at the point where it descends through the 50-foot height in the determination of the landing distance.
Regions of command
The regions of normal and reversed command refers to the relationship between speed and the power required to maintain or change that speed in flight.
REIL
Runway End Identifier Lights.
Relative bearing (RB)
The angular difference between the aircraft heading and the direction to the station, measured clockwise from the nose of the aircraft.
Relative bearing indicator (RBI)
Also known as the fixed- card ADF, zero is always indicated at the top of the instrument and the needle indicates the relative bearing to the station.
Release Time
A departure time restriction issued to a pilot by ATC (either directly or through an authorized relay) when necessary to separate a departing aircraft from other traffic.
Remote Communications Outlet (RCO)
An unmanned communications facility remotely controlled by air traffic personnel. RCOs serve FSSs and may be UHF or VHF. RCOs extend the communication range of the air traffic facility. RCOs were established to provide ground-to-ground communications between air traffic control specialists and pilots located at a satellite airport for delivering en route clearances, issuing departure authorizations, and acknowledging IFR cancellations or departure/landing times.
Reporting Point
A geographical location in relation to which the position of an aircraft is reported. (See Compulsory Reporting Points)
Required navigation performance (RNP)
A specified level of accuracy defined by a lateral area of confined airspace in which an RNP-certified aircraft operates.
Restricted Area
Airspace designated under 14 CFR Part 73, within which the flight of aircraft, while not wholly prohibited, is subject to restriction. Most restricted areas are designated joint use and IFR/VFR operations in the area may be authorized by the controlling ATC facility when it is not being utilized by the using agency. Restricted areas are depicted on en route charts. Where joint use is authorized, the name of the ATC controlling facility is also shown.
Reverse sensing
The VOR needle appearing to indicate the reverse of normal operation.
RF
Radio Frequency.
Right Base Area
A type of Terminal Arrival Area. A 30NM arc centered on the left corner IAF (Initial Approach Fix). The area shares a boundary with the straight-in area except that it extends out for 30NM from the IAF and is bounded on the other side by a line extending from the IF through the FAF to the arc.
Rigidity
The characteristic of a gyroscope that prevents its axis of rotation tilting as the Earth rotates.
Rime ice
Rough, milky, opaque ice formed by the instantaneous freezing of small supercooled water droplets.
RLSD
Released
RMI
Radio Magnetic Indicator.
RNAV
Area Navigation.
RNAV Approach
An instrument approach procedure which relies on aircraft area navigation equipment for navigational guidance.
RNAV DP
A DP developed for RNAV-equipped aircraft whose ground track is based on satellite or DME/DME navigation systems.
RNP
Required Navigation Performance.
ROC
Required Obstacle Clearance
Roll-out RVR
The RVR readout values obtained from sensors located nearest the rollout end of the runway.
RPAT
RNP Parallel Approach Runway Transitions
Runway end identifier lights (REIL)
A pair of synchronized flashing lights, located laterally on each side of the runway threshold, providing rapid and positive identification of the approach end of a runway.
Runway Incursion
An occurrence at an airport involving an aircraft, vehicle, person, or object on the ground that creates a collision hazard or results in a loss of separation with an aircraft that is taking off, intending to take off, landing, or intending to land.
Runway Profile Descent
An instrument flight rules (IFR) air traffic control arrival procedure to a runway published for pilot use in graphic and/or textual form and may be associated with a STAR. Runway Profile Descents provide routing and may depict crossing altitudes, speed restrictions, and headings to be flown from the en route structure to the point where the pilot will receive clearance for and execute an instrument approach procedure. A Runway Profile Descent may apply to more than one runway if so stated on the chart.
Runway Transition
A. Conventional STARs/SIDs. The portion of a STAR/SID that serves a particular runway or runways at an airport.
B. RNAV STARs/SIDs. Defines a path(s) from the common route to the final point(s) on a STAR. For a SID, the common route that serves a particular runway or runways at an airport.
Runway Visibility Value (RVV)
The visibility determined for a particular runway by a transmissometer. A meter provides a continuous indication of the visibility (reported in miles or fractions of miles) for the runway. RVV is used in lieu of prevailing visibility in determining minimums for a particular runway.
Runway Visual Range (RVR)
An estimate of the maximum distance at which the runway, or the specified lights or markers delineating it, can be seen from a position above a specific point on the runway centerline. RVR is normally determined by visibility sensors or transmissometers located alongside and higher than the centerline of the runway. RVR is reported in hundreds of feet.
RVR
Runway Visual Range.
RVSM
Reduced Vertical Separation Minimums
RVV
Runway Visibility Value.
RWY
Runway
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