# 1.2 Abbreviations and symbols.
In this chapter:
*AFM* means airplane flight manual.
*AGL* means above ground level.
*ALS* means approach light system.
*APU* means auxiliary power unit.
*ASR* means airport surveillance radar.
*ATC* means air traffic control.
*ATS* means Air Traffic Service.
*CAMP* means continuous airworthiness maintenance program.
*CAS* means calibrated airspeed.
*CAT II* means Category II.
*CMP* means configuration, maintenance, and procedures.
*DH* means decision height.
*DME* means distance measuring equipment compatible with TACAN.
*EAS* means equivalent airspeed.
*EFVS* means enhanced flight vision system.
*Equi-Time Point* means a point on the route of flight where the flight time, considering wind, to each of two selected airports is equal.
*ETOPS* means extended operations.
*EWIS*, as defined by § 25.1701 of this chapter, means electrical wiring interconnection system.
*FAA* means Federal Aviation Administration.
*FFS* means full flight simulator.
*FM* means fan marker.
*FSTD* means flight simulation training device.
*FTD* means flight training device.
*GS* means glide slope.
*HIRL* means high-intensity runway light system.
*IAS* means indicated airspeed.
*ICAO* means International Civil Aviation Organization.
*IFR* means instrument flight rules.
*IFSD* means in-flight shutdown.
*ILS* means instrument landing system.
*IM* means ILS inner marker.
*INT* means intersection.
*LDA* means localizer-type directional aid.
*LFR* means low-frequency radio range.
*LMM* means compass locator at middle marker.
*LOC* means ILS localizer.
*LOM* means compass locator at outer marker.
*M* means mach number.
*MAA* means maximum authorized IFR altitude.
*MALS* means medium intensity approach light system.
*MALSR* means medium intensity approach light system with runway alignment indicator lights.
*MCA* means minimum crossing altitude.
*MDA* means minimum descent altitude.
*MEA* means minimum en route IFR altitude.
*MEL* means minimum equipment list.
*MM* means ILS middle marker.
*MOCA* means minimum obstruction clearance altitude.
*MRA* means minimum reception altitude.
*MSL* means mean sea level.
*NDB (ADF)* means nondirectional beacon (automatic direction finder).
*NM* means nautical mile.
*NOPAC* means North Pacific area of operation.
*NOPT* means no procedure turn required.
*OEI* means one engine inoperative.
*OM* means ILS outer marker.
*OPSPECS* means operations specifications.
*PACOTS* means Pacific Organized Track System.
*PAR* means precision approach radar.
*PMA* means parts manufacturer approval.
*POC* means portable oxygen concentrator.
*PTRS* means Performance Tracking and Reporting System.
*RAIL* means runway alignment indicator light system.
*RBN* means radio beacon.
*RCLM* means runway centerline marking.
*RCLS* means runway centerline light system.
*REIL* means runway end identification lights.
*RFFS* means rescue and firefighting services.
*RNAV* means area navigation.
*RR* means low or medium frequency radio range station.
*RVR* means runway visual range as measured in the touchdown zone area.
*SALS* means short approach light system.
*SATCOM* means satellite communications.
*SSALS* means simplified short approach light system.
*SSALSR* means simplified short approach light system with runway alignment indicator lights.
*TACAN* means ultra-high frequency tactical air navigational aid.
*TAS* means true airspeed.
*TCAS* means a traffic alert and collision avoidance system.
*TDZL* means touchdown zone lights.
*TSO* means technical standard order.
*TVOR* means very high frequency terminal omnirange station.
*V*<sub>A</sub> means design maneuvering speed.
*V*<sub>B</sub> means design speed for maximum gust intensity.
*V*<sub>C</sub> means design cruising speed.
*V*<sub>D</sub> means design diving speed.
*V*<sub>DF</sub>/*M*<sub>DF</sub> means demonstrated flight diving speed.
*V*<sub>EF</sub> means the speed at which the critical engine is assumed to fail during takeoff.
*V*<sub>F</sub> means design flap speed.
*V*<sub>FC</sub>/*M*<sub>FC</sub> means maximum speed for stability characteristics.
*V*<sub>FE</sub> means maximum flap extended speed.
*V*<sub>FTO</sub> means final takeoff speed.
*V*<sub>H</sub> means maximum speed in level flight with maximum continuous power.
*V*<sub>LE</sub> means maximum landing gear extended speed.
*V*<sub>LO</sub> means maximum landing gear operating speed.
*V*<sub>LOF</sub> means lift-off speed.
*V*<sub>MC</sub> means minimum control speed with the critical engine inoperative.
*V*<sub>MO</sub>/*M*<sub>MO</sub> means maximum operating limit speed.
*V*<sub>MU</sub> means minimum unstick speed.
*V*<sub>NE</sub> means never-exceed speed.
*V*<sub>NO</sub> means maximum structural cruising speed.
*V*<sub>R</sub> means rotation speed.
*V*<sub>REF</sub> means reference landing speed.
*V*<sub>S</sub> means the stalling speed or the minimum steady flight speed at which the airplane is controllable.
*V*<sub>S</sub><sub>0</sub> means the stalling speed or the minimum steady flight speed in the landing configuration.
*V*<sub>S</sub><sub>1</sub> means the stalling speed or the minimum steady flight speed obtained in a specific configuration.
*V*<sub>SR</sub> means reference stall speed.
*V*<sub>SR</sub><sub>O</sub> means reference stall speed in the landing configuration.
*V*<sub>SR</sub><sub>1</sub> means reference stall speed in a specific configuration.
*V*<sub>SW</sub> means speed at which onset of natural or artificial stall warning occurs.
V<sub>TOSS</sub> means takeoff safety speed for Category A rotorcraft.
*V*<sub>X</sub> means speed for best angle of climb.
*V*<sub>Y</sub> means speed for best rate of climb.
*V*<sub>1</sub> means the maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. V<sub>1</sub> also means the minimum speed in the takeoff, following a failure of the critical engine at V<sub>EF</sub>, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.
*V*<sub>2</sub> means takeoff safety speed.
*V*<sub>2min</sub> means minimum takeoff safety speed.
*VFR* means visual flight rules.
*VGSI* means visual glide slope indicator.
*VHF* means very high frequency.
*VOR* means very high frequency omnirange station.
*VORTAC* means collocated VOR and TACAN.
[Doc. No. 1150, 27 FR 4590, May 15, 1962]
For citations affecting § 1.2, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at