aviation terms

帅哥

ONC Operational Navigation Chart 6 V) R5 p+ C y7 O) p. GOPERATE to use or authorize to use aircraft, for the purpose (except as provided in Sec. 91.13 of this chapter) of air navigation including the piloting of ai... OPERATIONAL CONTROL with respect to a flight, means the exercise of authority over initiating, conducting or terminating a flight. OPERATIONAL DEVIATION (OD) An occurrence where applicable separation minima, as referenced in the operational error definition below were maintained, but: (1) less than the appl... OPERATIONAL ERROR (OE) An occurrence attributable to an element of the air traffic control system which results in less than the applicable separation minima between two or ... OPERATIONS How well is equipment operating; Values: operational (all function and data is available), degraded (equipment has partially failed with some function... 5 g# s" G; I6 i+ X" |/ k3 \OPS Operations (or Operating hours) ; ~1 Z' D { a% o$ l8 R' z/ S7 }8 cOPTICAL DIGITIZER Any device using a photo sensor that can convert analog information to digital code ORD Operational Requirements Document 7 K9 _8 D! [' t2 z2 i3 TORIENTATION Direction in reference to a coordinate frame 0 m* J P' Y+ LOUT Operational Training Unit OUTER MARKER Marker beacon located 5-7mi from the end of the runway; See Also: marker beacon OUTSIDE AIR TEMPERATURE (OAT) The temperature just outside the aircraft; Symbols: T; Typical Units: deg; Dimensions: Temperature OVER-THE-TOP above the layer of clouds or other obscuring phenomena forming the ceiling OVERIDE To alter selection made automatically by software : _' \, o$ {* f" L5 x _OVERSEAS AIR COMMERCE the carriage by aircraft of persons or property for compensation or hire, or the carriage of mail by aircraft, or the operation or navigation of aircr... + R) X9 f" H9 Z1 T: L8 r$ LOVERSEAS AIR TRANSPORTATION the carriage by aircraft of persons or property as a common carrier for compensation or hire, or the carriage of mail by aircraft, in commerce: (1) Be... OXY Oxygen system for passengers and crew P/P per person, per passenger PAN-PAN The international radio-telephony urgency signal. When repeated three times, indicates uncertainty or alert followed by the nature of the urgency. ! g5 ~; e9 L7 ~& o& x1 S% l. g! o$ [PANS Procedures for Air Navigation Services (ICAO) ( b. n9 W, j; o# R* wPAPI Precision Approach Path Indicator PAR Precision Approach Radar - a ground-radar based instrument approach which provides both horizontal and vertical guidance 9 l7 H) D% A Q9 `- Y6 N* Z7 ?4 APARACHUTE a device used or intended to be used to retard the fall of a body or object through the air PART Precision Approach Radar . E9 K$ e% ?3 V9 tPAST STATUS WORDS Status words that are logically combined over time (such as "and "ing or "or "ing) to provide history of what has been set in the past PATH INTEGRAL GAIN (KINT) A guidance control law parameter, generated by the lateral guidance modes;

帅哥

PATH INTEGRAL LIMIT (INTLIM) A guidance control law parameter, generated by the lateral guidance modes; Typical Units: rad; 9 d2 v6 R# C3 ] }! a7 W- fPATH INTEGRAL VALUE (INTVAL) A guidance control law parameter, generated by the lateral guidance modes; Typical Units: ft; Dimensions: Length PAX Passenger (s) 2 }$ s+ r; N( @. Y& P8 oPAYLOAD WITH FULL FUEL Useful Load - (minus) Usable Fuel ; C0 c7 X/ k/ l$ B8 c gPBH Power by the Hour. (Rolls Royce engines) 6 p7 ^' G% ?- T0 M+ J1 SPBIT Periodic built-in-test * h/ Q& ~& P8 _. ?, RPC Positive Control. (Trade name for Mooney Aircraft wing leveler) PCL Pilot Controlled Lighting (RWY Lights operated by Microphone) 1 P% X' m! R6 P! h6 }% CPCM Pulse Code Modulation. A modified FM signal used in high end radios. The signal is coded by the transmitter, resulting in a cleaner signal. PEAK This is the point at which a battery will no longer accept a charge, and converts the energy to heat. This is damaging to the battery pack, and potent... 2 e2 l4 F- l O% v. A0 cPEAK CHARGER This type of charger will eliminate the guesswork. When the battery has reached peak, the charger reverts to a maintenance charge rate, which will not... PEAK POWER OUTPUT The maximum transmitter power output measured over a short time; usually used to rate pulse transmissions. 5 U y3 y# I: x+ X+ T# d: ^PED Personal Electronic Devices (e.g. Walkman, Handy etc.) PEDAL A flight control operated by pushing with feet, primarily to control yaw via the rudder in fixed-wing aircraft or thrust to tail rotor in rotary-wing ... 6 x/ b8 \9 Y4 @ w A% ?PEP Peak envelope power. A standard electronic rating of any AC source, including a radio transmitter PERFECTOS RAF airborne radar used to home on the IFF equipment carried by the German night fighters. PERIOD Time of a periodic process; 1/f where f is the sampling frequency; Symbols: T; Typical Units: s; Dimensions: Time. PERIODIC A process that executes at a fixed rate; Compare: a periodic; PERIODIC BUILT-IN-TEST (PBIT) Self tests running internal to a device as part of normal operation; Compare: initiated built-in-test; + ~/ e t3 _3 c' {4 ~- ?& i# Y8 EPERSON an individual, firm, partnership, corporation, company, association, joint-stock association, or governmental entity. It includes a trustee, receiver,... 7 K: h6 n1 |# B" x8 Q2 vPERSONNEL LOCATING SYSTEM (PLS) A basic guidance mode, providing lateral guidance to a PLS transmitter from range and bearing inputs. Equipment that determines range and bearing to a... + H4 L { \$ h% y" ]7 w+ dPETAL Preliminary Euro control Trial Air/ground Data Link PFCS Primary flight control system 2 S( e4 v& N. H$ x. L3 C) v# `PFF PATHFINDER FORCE. Small group of aircraft which, after finding the target, put down flares to guide the following bombers. PGL Parlamentarische Gruppe fìr Luftfahrt

帅哥

PHYSICAL DEVICE A piece of equipment, a subsystem; Synonyms: device PIC Pilot in Command PILOT DEVIATION (PD) The actions of a pilot which result in the violation of a Federal Aviation Regulation (FAR) or a North American Aerospace Defense Command (NORAD) Air ... ; }4 S8 j% W6 Q9 W3 s# ~) BPILOT IN COMMAND (PIC) The pilot responsible for the operation and safety of an aircraft during flight time. PILOTAGE Navigation by visual reference to landmarks. PILOTED LIMULATION Real-time engineering simulation 7 B: o# H' d' @0 ^PIPERACK British airborne jamming device PIREP Pilot (weather) Report & H) g3 l7 G0 W2 H) L* b/ G4 BPITCH Describes the fore and aft attitude of the aircraft. (Nose high or low in comparison to the ground.) Controlled by the elevator (s). - @4 i$ G% ~9 M$ _PITCH AXIS The airplane axis controlled by the elevator. Pitch is illustrated by holding the airplane at each wingtip. Raising or lowering the nose is the pitch ... PITCH CUE Flight director cue to control pitch; in fixed-wing aircraft, a yoke cue; in rotary-wing aircraft, a longitudinal cyclic cue 3 p+ Y( E% F& GPITCH RATE Rate of change of pitch; time derivative of pitch; Symbols: p; Symbols: theta dot; Typical Units: rad/s, deg/s; Dimensions: 1/Time; PITCH SETTING the propeller blade setting as determined by the blade angle measured in a manner, and at a radius, specified by the instruction manual for the propel... ! j, v! }' s" xPITOT PRESSURE Total pressure PLS Personnel Locating System A: I/ |: T0 n" n, d; b& g5 WPLY Plywood ) ^9 H5 y# S; o) j! x. LPNR Prior Notice Required PNT Paint 1 J* R8 B7 A- M: Z! L& j, [" tPOB Persons on Board PONTOONS See Floats. PORT Nautical usage adopted in aviation. The left side, as determined by an observer in the vehicle, when vehicle and observer are right side up, and obser... POSITION Location, usually in fixed earth coordinates such latitude and longitude; location, either scalar or vector, often with subscripts such as ENU or XYZ ... POSITION UPDATE To cause navigation sensors, devices, or algorithms to reset position to value known to be more accurate due to inaccuracies and drift in the devices ... POSITIVE CONTROL The separation of all air traffic within designated airspace by air traffic control. POST KLYSTRON German jamming device to counter H2S POWER PANEL 12-volt distribution panel that provides correct voltage for accessories like glow-plug clips, fuel pumps and electric starters. Usually mounted on a ... 9 h0 N0 m$ U$ }* \8 h: B: D7 xPP(L) Private Pilots License (general) PPL A Private Pilots License Airplane

帅哥

PPL H Private Pilots License Helicopter PPL/IR Association of PPL holders with Instrument Rating 1 ~* C/ b& s E* `' z: w* dPPM Pulse Position Modulation. Another term for FM. PPO Parts Per Million PPP Public Private Partnership 9 ]7 H- H3 ?# W K, i# ZPPR Prior Permission Required PRC Performance Review Commission (Euro control) . P' o' e& \0 n& PPRECISION Measure of exactness, possibly expressed in number of digits, for example, computed to the nearest millimeter; Compare: accuracy PRECISION APPROACH PROCEDURE means a standard instrument approach procedure in which an electronic glide slope is provided, such as ILS and PAR. PRESENT STATUS WORDS Most recently reported status words PRESSURE Barometric pressure PRESSURE ALTITUDE Barometric altitude PREVENTIVE MAINTENANCE means simple or minor preservation operations and the replacement of small standard parts not involving complex assembly operations. Prohibited area. ... PRIMARY FLIGHT CONTROL SYSTEM(PFCS) The most basic part of the flight controls operated by a pilot, including wheel (fixed wing), yoke (fixed wing), cyclic (rotary wing), pedals (fixed w... PRIMARY UNITS A standard set of four units to which all units can be resolved; primary units are Mass (M), Length (L), Time (theta), and Temperature (T); for exampl... / U: n* J5 n/ i7 \- I7 n/ X( W# @. APRIME RADIUS OF CURVATURE Radius of the earth in the east/west direction at a given position; Synonyms: earth radius east/west; Symbols: rho sub P; Typical Units: ft; Dimension... PRK Photo Refractory Keratomy (eye surgery) - Q9 d9 Y Z/ SPRNAV Precision RNAV (RNP-1 or less compliant) PROP BALANCER Device designed to aid in the balancing of aircraft airplane propellers. PROPELLER means a device for propelling an aircraft that has blades on an engine-driven shaft and that, when rotated, produces by its action on the air, a thrus... PRR Performance Review Report E7 `/ {; O' @& j9 a- w0 G9 zPSG Program Steering Group PSI Pounds per square inch. + n2 m6 Y* U+ N3 EPSIA Pounds per square inch PT Procedure Turn

帅哥

PTT Push-to-talk (switch) PULL-PULL A linkage set up using two rods or wires. One is pulled for one direction, the other is pulled for the other. 8 F! A9 V: |5 S. y* H: `PULSE A transmission of very brief duration used to carry information by using time measurement or as a series of pulses representing code. ( u$ Z, T* j, C* @" WPUSH-PULL A linkage set up using two rods. One rod pushes, while the other pulls. ) Z1 h/ g! G6 fPVT Private (pilot certificate) PW Pratt " l. k( [" p6 a* kQDM (Q-Code) for Homing Track to a Station % T9 i" l' z! |" n. K+ ~QDR private : D w7 {" @# o$ \5 ]- ~) _QFE (Q-Code) for Air Pressure in hPa on Ground (airport elevation) . R/ I5 |( x% J+ M) jQGO (Q-Code) for Airport Closed $ N1 P' d# y; p2 YQNH (Q-Code) for Air Pressure in hPa calculated to MSL QUAMGO Quasi-Monopoly Government Organization % u" r; A; M+ y7 V6 [QUATERNION A system of representing attitude by measuring angle of aircraft center line with respect to three orthogonal axes plus rotation about centerline; qua... ' A P6 A' A/ i5 L6 i" t, GR Rating R Research and Development 7 P# x& x0 u4 z' g3 NRA (1) Radio altitude; (2) Resolution advisory (TCAS) RADAL Radio Altimeter RADALT Radar Altimeter. RADAR On-board weather radar. RADAR ALTIMETER Device that senses aircraft`s height above the terrain. Different from normal (barometric) altimeter. RADAR ALTIMETER (RADALT) Measures height above terrain. The altitude is monitored to provide a low altitude warning during TF operations and landing operations. It can also be... RADAR ALTITUDE Height with respect to the terrain below (distance above closest dirt); Synonyms: above ground level; Symbols: h sub r; Typical Units: ft; Dimensions:... RADAR ALTITUDE SELECT (RALTSEL) A basic guidance mode, providing vertical guidance to an operator selected radar altitude; 2 y: J+ ~. O: H! ~- d3 ]* QRADAR APPROACH CONTROL FACILITY(RAPCON) A terminal ATC facility that uses radar and non radar capabilities to provide approach control services to aircraft arriving, departing, or transiting... + b9 V+ E6 _# q' a! y" HRADIAL ERROR PROBABILITY (REP) A probability that a percentage of one-dimension measurements will lie on a radial (line) of given length, with the origin centered at truth or mean o...

帅哥

RADIO MAGNETIC INDICATOR (RMI) An ADF-like display with a pair of pointers which might be attached to either VOR or ADF receivers $ i0 h6 o2 t c0 sRADIO NAVIGATION Navigation relative to radio station, providing, for example, of relative bearing, range, lateral deviation, and glide slope; Examples include VOR, TA... ; O6 }) O& P$ Z" KRADOME A detachable nose cone made of plastic-type material, used to cover and protect an airplane`s radar antenna. 5 h' S$ M$ g- K3 ?RAF Resolution Advisory (TCAS) ; W. J8 z( q9 x' hRAIL runway alignment indicator light system. RAIM Receiver autonomous integrity monitoring (GPS) % ~& ]* z0 i# [" g5 ORALT SEL Radar altitude select RAM Random Access Memory RAMJET A type of jet engine with very few moving parts which consists of a specially shaped tube open at both ends. 8 d& P* X0 Y+ D, ]RAMP An airfield parking lot for aircraft. 9 w, J6 |! l' i( @# tRAMROD A tactical bombing mission with fighter escort RANGE (RNG) Standard aviation term Synonyms: distance; Symbols: r; Typical Units: ft, nmi - method of measurement dependent on use; Dimensions: Length; RANGER Similar to Circus but usually a deep penetration operation RANGING Act of determining a range / P* p( B4 P; s. D- r5 K t7 a! rRATE LIMITER A filter that passes the input as the output, except that rate of change of the output is limited to a maximum absolute value; Compare: limiter; " r1 Y) o" z+ f/ ~RATE OF CLIMB (ROC) The speed at which an aircraft is gaining (or losing) altitude, usually measured in hundreds or thousands of FPM. RATE OF ROLL A measure of the speed with which an airplane can turn around its long axis, or roll. 2 U" R$ \6 W. X& k0 NRATED 2 1/2 -MINUTE OEI POWER with respect to rotorcraft turbine engines, means the approved brake horsepower developed under static conditions at specified altitudes and temperatu...

帅哥

RATED 30-MINUTE OEI POWER with respect to rotorcraft turbine engines, means the approved brake horsepower developed under static conditions at specified altitudes and temperatu... RATED CONTINUOUS OEI POWER with respect to rotorcraft turbine engines, means the approved brake horsepower developed under static conditions at specified altitudes and temperatu... $ Z8 d F. T( Z! M: {RATED MAXIMUM CONTINUOUS AUGMENTEDTHRUST with respect to turbojet engine type certification, means the approved jet thrust that is developed statically or in flight, in standard atmosphere at... ' X8 {2 ^( s$ fRATED MAXIMUM CONTINUOUS POWER with respect to reciprocating, turbo propeller, and turbo shaft engines, means the approved brake horsepower that is developed statically or in flight... ) K/ x' ?6 k; Y+ ~3 c5 w9 T7 @RATED MAXIMUM CONTINUOUS THRUST with respect to turbojet engine type certification, means the approved jet thrust that is developed statically or in flight, in standard atmosphere at... + {2 F6 @) z2 \( y2 p5 {RATED TAKEOFF AUGMENTED THRUST with respect to turbojet engine type certification, means the approved jet thrust that is developed statically under standard sea level conditions, wi... RATED TAKEOFF POWER with respect to reciprocating, turbo propeller, and turbo shaft engine type certification, means the approved brake horsepower that is developed stati... 3 ?: g3 Q6 @* @; ERATED TAKEOFF THRUST with respect to turbojet engine type certification, means the approved jet thrust that is developed statically under standard sea level conditions, wi... ; g8 q. \- N2 J' \; Z0 eRATING means a statement that, as a part of a certificate, sets forth special conditions, privileges, or limitations 6 x3 s( g' v0 C( d6 B. N0 FRAW Data taken directly from the sensor; Compare: derived, estimated, filtered, measured, selected, smoothed RAYON ; Ground-based interference of KNICKEBEIN in night fighter control ! v( f8 y8 U: R- bRAZZLE Phosphorous coated wooden strips transported in water Razzles were designed to fire crops and forests but with negligible effect. ) x o0 J; ] h8 H9 t$ k! {RB Relative Bearing (NAV) 8 @& S, W0 h5 K- wRBAS Receiver Based Augmentation System (DGNSS/DGPS) / O+ r! U! C. B$ s- kRBN radio beacon. ' J! r( q6 D3 g( z. ARCA Avionics mfr.

帅哥

RCLM runway centerline marking. ! b2 A$ X9 w; w: m |RCLS runway centerline light system. # G k$ Y5 d/ W; {RCU Radio control unit. " F6 }7 ]* [3 d& [RDF Radio Direction Finding. A name first used for what became Radar RDX Powerful explosive first used in the Barnes Wallis bouncing bomb REA Recommended Crossing Altitude REAL TIME Time in a computational process which runs at the same rate as a physical process; for example, algorithms designed to run a fixed period t (filter ti... REAL-TIME ENGINEERING SIMULATION(RTES) A simulator designed to test avionics algorithms with a pilot in the loop, consisting of a simulated cockpit, an aircraft model, sensor models, and al... REASONABLENESS A test to determine if data is reasonable, for example, radar altitude must be positive, and two devices should return similar data within known limit... + \- | l7 q4 x; e& M) |" \REBECCA The airborne interrogator end of a two-part system using a ground beacon called EUREKA. Designed as a homing system for the identification of ground f... RECEIVE To absorb rf energy 7 O0 S. P, r+ H" F9 |: `( vRECEIVER (RX) The radio unit in the airplane which receives the transmitter signal and relays the control to the servos. This is somewhat similar to the radio you m... REDLINE For a given airplane, the airspeed above which it is unsafe to fly. Redlining the plane may over stress or even damage structural elements in the plan... $ s+ ] x+ i" k5 ]4 u# u0 r. qREFACC Reference acceleration REFERENCE What must be achieved in order to match a plan; Synonyms: desired; 6 \( e, d! ~' }* {! X: {+ }REFERENCE ACCELERATION (REFACC) A guidance control law parameter, generated by the longitudinal guidance modes; Typical Units: ft/s-squared, g; Dimensions: Length / Time-squared : y! F5 A# L5 P& O( F6 C& cREFERENCE ACCELERATION GAIN(KLA) A guidance control law parameter, generated by the longitudinal guidance modes; Typical Units: s; Dimensions: Time. " S# u" }! A9 _2 G2 PREFLEX If a wing has an airfoil that curves down from the high point, and then curves back up, it`s said to be "reflexed". Reflex is the size of that reverse... ( `5 F' K0 C! l+ {REIL Runway End Identifier Lights

帅哥

REJECT To disallow a position update, usually by an operator; Compare: accept 9 Z( L6 I# o6 ~RELATIVE Applies to measurements, in a non-standard, moving reference, as opposed to fixed reference; Compare: absolute; RELATIVE BEARING Angle from aircraft center line to bearing of the destination; Symbols: B sub R; Typical Units: rad, deg; 5 [9 c5 h2 J" x. V7 lREMOTE TERMINAL (RT) Term defining role of a device on a MIL-STD-1553 bus as being a slave; Compare: bus controller; 3 P, A9 ~% R* y% DREMOTE TERMINAL UNIT Signal Data Converter; & W4 C( ?7 ]2 o& y6 \) A1 Z: d2 MRENDEZVOUS To meet with another aircraft in the air, for refueling or other mission objectives / U3 N5 y, _3 D3 I, o$ ]: g- yRENDEZVOUS APPROACH To approach a planned rendezvous point 8 d! ^$ F- [3 k' R2 z, vREP Radial error probability REPORTED Data from a device & _, [' X; |' |7 |1 `REPORTING POINT means a geographical location in relation to which the position of an aircraft is reported. Restricted area. A restricted area is airspace designated ... RESONANCE This is the vibration frequency of a rotating or moving object. When the resonance of many parts of a machine are in synch, the whole machine will vib... # n ]0 R5 `# c8 |RETRACT SERVO Specifically used for mechanical retracts. It is a non-proportional servo which only moves 180 degrees. That is to say this servo is either "off" (gea... ! E- I& r. ^% F3 uRETRACTS Short for retractable landing gear. Wheels and struts that fold up into the airplane to get them out of the air stream and present less resistance to ... 8 P! o/ i* C% W# n2 ~1 MREVENUE Pertaining to activities for which remuneration is received by the carrier. ' O: O' s8 g" B0 l y9 G# tREVERSERS System for braking aircraft during landing roll. RF Radio Frequency ! m$ Q- Y! L6 D+ ^4 t0 kRFI Request For Improvement Message (slot) RFP Reglement ìber die Ausweise fìr das Flugpersonal $ k. r, C. f, m5 wRFU Radio frequency unit. RG Retractable landing gear. RH Right-hand ; i+ |. T* |7 g& rRHUBARB Low-level tactical operation from cloud cover.

帅哥

RIA Regulatory Impact Assessment : e: Q' D' g; K2 j0 w/ ~RIGHT THRUST Right yaw angle of the engine relative to the centerline of the airplane. Right thrust helps overcome the normal yaw tendency caused by the torque of ... 4 a6 g3 F" D3 i7 c$ NRIMS Remote Integrity Monitoring Station (?) - p# r) q2 t% [$ b! oRING-LASER GYRO (RLG) A gyroscope based on a laser beam instead of a rotating mass, providing to same data as a gyroscope; 2 O7 V0 X# d5 O1 b/ k5 L* y, L8 DRINGED An engine which uses a piston with a piston ring. Compare to ABC or ABN. Best used in dusty environments, a ringed engine is less susceptible to damag... & Y f4 c n2 L% B& w* m! h4 RRLG Ring-laser gyro # f9 f# ~' }" U4 C2 ZRM Regional Meeting 4 }: M' A/ o, {& r; {+ b9 HRMI Radio Magnetic Indicator RMK Remark (s) 4 H- y G" O! x3 ~RMS Root mean square; % k1 t! x' {2 nRNAV Area navigation device. 7 W7 \ Q* ]; \+ d1 \6 H4 sRNAV WAY POINT (W/P) a predetermined geographical position used for route or instrument approach definition or progress reporting purposes that is defined relative to a VO... RNG Range ! K) \0 T/ P3 ? p& ~) i$ F8 m* c/ pRNP Required navigation performance. 3 K# M) A6 Q0 q5 o; a* O3 V2 e7 jRNP-N Area Navigation Q0 E0 Z1 o% W' G3 {! _7 T/ S) HRNSS Radio Navigation Satellite Services k7 b7 c- Y- Y# I5 n- P! E( OROADSTEAD Anti-shipping strike by fighters. Codenamed ROVER in Coastal Command. * _: t9 @3 m: I$ p# Q, R$ EROC Rate of Climb ROCKET an aircraft propelled by ejected expanding gases generated in the engine from self-contained propellants and not dependent on the intake of outside su... 1 T8 s2 Q$ [$ ~6 i& O( T" ~RODEO A general fighter sweep over occupied territory. ) d; K6 c- N, N! V: d6 X' cRODERICH German jamming device to counter H2S ) A8 P/ _5 r/ A, y0 V1 S- H* PROLL AXIS The airplane axis controlled by the ailerons. Roll is illustrated by holding the airplane by the nose and tail. Dropping either wingtip is the roll mo... 8 M% ]5 A/ ? q( _8 c: @ROLL CUE Flight director cue to control roll; in fixed-wing aircraft, a wheel cue; in rotary-wing aircraft, a lateral cyclic cue / ^- Z1 s8 C" A; i! m4 bROLL RATE Rate of change of roll; time derivative of roll; Symbols: q; Symbols: phi dot; Typical Units: rad/s, deg/s; Dimensions: 1/Time; . o6 W0 ]' U( v, @4 sROM Read-only memory.