Subpart B - Abbreviations

1.51 Purpose

(a) This Subpart specifies the abbreviations applicable to and within the OTARs and any associated OT Aviation Circulars.

(b) Unless the context otherwise requires or the term is defined otherwise in relation to a particular Part of these OTARs the meaning of abbreviations is as given in 1.53.

1.53 Abbreviations

AC Alternating current

ACAS Airborne collision avoidance system

ACN Aircraft classification number

AD Airworthiness directive

ADF Automatic direction-finder

ADREP Accident/incident reporting

ADRS Aircraft data recording system

ADS Automatic dependent surveillance

ADS-B Automatic dependent surveillance – broadcast

ADS-C Automatic dependent surveillance – contract

AFCS Automatic flight control system

AFS Aeronautical fixed service

AFTN Aeronautical fixed telecommunication network

AGA Aerodromes, air routes and ground aids

AGL Aerodrome ground lighting OR Above ground level

AIC Aeronautical Information Circular

AIG Accident investigation and prevention

AIP Aeronautical Information Publication

AIR Airborne image recorder

AIRS Airborne image recording system

AIS Aeronautical information service

AME Aircraft maintenance engineer OR Approved medical examiner

AMEL Aircraft maintenance engineer’s licence

AMSL Above mean sea level

AOC Air operator’s certificate

AN(OT)O Air Navigation (Overseas Territories) Order

AN(OT)(ES)O Air Navigation (Overseas Territories) (Environmental Standards Order

APU Auxiliary power unit

ARFL Aeroplane reference field length

ASDA Accelerate-Stop distance available

ASSI Air Safety Support International Ltd

ATC Air traffic control

ATIS Automatic terminal information service

ATM Air traffic management

ATPL Airline Transport Pilot Licence

ATS Air traffic services

ATZ Aerodrome traffic zone

AWS Automatic weather station


BRNAV Basic area navigation


CARS Cockpit audio recording system

CAS Calibrated airspeed

CAT I Category I

CAT II Category II

CAT III Category III




Cd Candela

Cm Centimetre

CDL Configuration deviation list

CDFA Continuous descent final approach

CFIT Controlled flight into terrain

CMV Converted meteorological visibility

CPDLC Controller-pilot data link communications

CPL Commercial Pilot Licence

CRM Crew resource management

CVR Cockpit voice recorder


DA Decision altitude

D-ATIS ATIS provided via data link

DA/H Decision altitude/height

DC Device control

DCA Director of Civil Aviation

DF Direction finding

DFLD Database Field Loadable Data

D-FIS Data link-flight information services

DH Decision height

DLR Data link recorder

DLRS Data link recording system

DME Distance measuring equipment

DPATO Defined point after take-off

DPBL Defined point before landing

DSTRK Desired track


EASA European Aviation Safety Agency

EAT Expected approach time

ECAM Electronic centralised aircraft monitor

EDTO Extended diversion time operations

EET Estimated elapsed time

EFIS Electronic flight instrument system

EGPWS Enhanced Ground Proximity Warning System

EGT Exhaust gas temperature

EICAS Engine indication and crew alerting system

ELT Emergency locator transmitter

ELT(AD) Automatically deployable ELT

ELT(AF) Automatic fixed ELT

ELT(AP) Automatic portable ELT

ELT(S) Emergency locator transmitter (survival)

EPIRB Emergency position indicating radio beacon

EPR Engine pressure ratio

ETA Estimated time of arrival

EUROCAE European Organization for Civil Aviation Equipment

EVS Enhanced vision system


FAR Federal Aviation Regulations issued by the Federal Aviation Administration of the United States of America

FATO Final approach and take off area

FDAU Flight data acquisition unit

FDPS Flight data processing system

FDR Flight data recorder

FIR Flight information region

FL Flight level

FLS Field Loadable Software

FM Frequency modulation

FOI Flight Operations Inspector

FOD Foreign object damage

ft Foot/feet

ft/min Feet per minute


g Normal acceleration

GA General aviation

GBAS Ground based augmentation system

GCAS Ground collision avoidance system

GLS GNSS landing system

GNSS Global navigation satellite system

GPS Global positioning system

GPWS Ground proximity warning system


HF High frequency

hPa Hectopascal

HUMS Health and usage monitoring system

HUD Head-up display

HUDLS Head-up guidance landing system


” Inches

ICAO International Civil Aviation Organisation

IFR Instrument flight rules

IFSD In-flight shut down

ILS Instrument landing system

IMC Instrument meteorological conditions

INS Inertial navigation system

IRVR Instrumented Runway Visual Range

ISA International standard atmosphere


JAR Joint aviation requirement


kg Kilogram

kg/m2 Kilogram per square metre

km Kilometre

km/h Kilometre per hour

KT Knots


lb Pound

LDA Landing distance available

LIFUS Line flying under supervision

LLZ Localiser

LRNS Long range navigation system

LRU Line Replaceable Unit

LVP Low visibility procedures

LVTO Low visibility take-off


m Metre

MDA Minimum descent altitude

MDA/H Minimum descent altitude/height

MDH Minimum descent height

MEL Minimum equipment list

MHz Megahertz

MLS Microwave landing system

MMEL Master minimum equipment list

MNPS Minimum navigation performance specifications

MOPS Minimum operational performance specification

MTOM Maximum certificated take-off mass

m/s Metres per second

m/s2 Metres per second squared


N Newton

N1 High pressure turbine speed

N2 Fan speed

N3 Compressor speed

NAA National aviation authority

NAV Navigation

NDB Non-directional radio beacon

NDT Non-destructive testing

NM Nautical mile


OCA Obstacle clearance altitude

OCA/H Obstacle clearance altitude/height

OCH Obstacle clearance height

OLS Obstacle Limitation Surfaces

OT Overseas Territory

OTAC Overseas Territories Aviation Circular

OTAR Overseas Territories Aviation Requirement


PANS Procedures for Air Navigation Services

PAPI Precision approach path indicator

PBN Performance Based Navigation

PCN Pavement classification number

PPL Private Pilot Licence


QFE Atmospheric pressure at aerodrome level or at runway threshold

QNH Altimeter sub-scale setting to obtain elevation when on the ground


R Rotor radius

RA ACAS Resolution advisory

RCC Rescue Coordination Centre

RCP Required communication performance

RDPS Radar data processing system

RESA Runway end safety area

RFR Radio frequency

RFDPS Radar and flight data processing system

RFFS Rescue and fire fighting services

RNAV Area navigation

RNP Required navigation performance

RPM Revolutions per minute

RVR Runway visual range

RVSM Reduced vertical separation minimum


SAp Stabilised approach

SAR Search and rescue

SEIFR Single-engine IFR

SELCAL Selective calling system

SOP Standard operating procedures

STOL Short take-off and landing

STD Synthetic Training Device


TA ACAS Traffic alert

TAS True airspeed

TAWS Terrain awareness and warning system

TCAS Traffic alert and collision avoidance system (see ACAS)

TLA Thrust lever angle

TODA Take-off distance available

TORA Take-off run available

TSO Technical standard order that is issued by the Federal Aviation Administration of the United States of America


UHF Ultra high frequency

UTC Co-ordinated universal time


V1 Take-off decision speed

V2 Initial climb out speed

VD Design diving speed

VEF Calibrated speed at which the critical engine is assumed to fail

VMC Minimum control speed with the critical engine inoperative

VREF Landing approach speed, all engines operating

VS Stalling speed

VSO Stalling speed or the minimum steady flight speed in the landing configuration

VS1 Stalling speed or the minimum steady flight speed in a specified configuration

VY Best rate of climb speed

VAAC Volcanic ash advisory centre

VCR Visual control room

VFR Visual flight rules

VHF Very high frequency

VMC Visual meteorological conditions

VOLMET Meteorological information for aircraft in flight

VOR VHF omnidirectional radio range

VSM Vertical separation minima

VTOL Vertical take-off and landing


ZFT Zero flight time

Change Information

  1. First Issue - published for information June 2004
  2. Second Issue - published for information April 2005
  3. Third Issue - released for gazetting July 2005
  4. Fourth Issue June 2006
  5. Fifth Issue August 2006
  6. Sixth Issue January 2008
  7. Seventh Issue November 2009
  8. Eighth Issue July 2010
  9. Ninth Issue January 2011
  10. Tenth Issue January 2012
  11. Eleventh Issue May 2016
  12. Twelfth Issue August 2017


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