Acronym Guide

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AAAE – American Association of Airport Executives (

ACAS – Airborne Collision Avoidance System

ACARS – Aircraft communications addressing and reporting system

AD – Airworthiness Directive (FAA). A notification to an aircraft owner and operator of a known safety deficiency with a particular model of aircraft, engine, avionics or other system. An AD requires mandatory compliance with the described corrective action.

ADF – Automatic Direction Finding. Ground based aircraft navigation equipment. Older technology.

ADS-B – Automatic Dependent Surveillance – Broadcast. A system by which an aircraft broadcasts its position, altitude, speed and direction of flight. The FAA has proposed that all aircraft have ADS-B (out) capability by 2020; ADS-B (in) capability will come later, at which time all aircraft in the system will know the position and flight path of every other aircraft in their vicinity.

ADIZ – Air Defense Identification Zone. A controlled airspace that serves as a national defense boundary for aerial incursions. Any aircraft flying in these zones without authorization may be identified as a threat and treated as an enemy aircraft, potentially leading to interception by a military authority.\

AED – Automated External Defibrillator

AFM – Aircraft Flight Manual. An aircraft operating manual. The FAA requires a current copy of the AFM to be carried aboard the aircraft when in flight.

AGL – Above Ground Level. An aeronautical term referring to the height of an aircraft above the terrain.

AI (interchangeably IA) – Authorized Inspector/Inspection Authorization. An FAA certificated professional maintenance technician authorized to inspect other technician’s work.

AIM – Aeronautical Information Manual.

AIN – Aviation International News (a trade publication) Available in print and on line.

AIP – Aeronautical Information Publication

AMO – Approved Maintenance Organization

AMP – Alertness Management Program, a.k.a. Fatigue Management Program. An integrated alertness management program addresses fatigue education, alertness strategies, scheduling, and healthy sleep. For more information: 

ANS – Air Navigation System

AOC – Aircraft Operating Certificate. The ICAO equivalent to a Part 135 Certificate in the U.S. Within the European Union holders of an air operator’s certificate are allowed to carry passengers, mail and/or cargo for payment. A license cannot be granted unless the carrier is registered in the related member state and controlled by community nationals.

AOC – Airline Operations Center. The location from which airline operational control is exercised.

A & P – Airframe & Powerplant maintenance technician. An individual certified by the FAA to perform aircraft maintenance.

APU – Auxiliary Power Unit. A small (typically turbine powered) on-board engine that supports an aircraft’s support equipment (hydraulics, electronics, heating and air conditioning) when the main engines are not operating (usually on the ground).

ARAC – Aviation Rulemaking Advisory Committee. Assigned by a Federal agency (like the FAA) to assist in the development of new rules.

ARFF – Airport Rescue Fire Fighters.

ARSA – Aeronautical Repair Station Association. International trade group for certificated stations. Includes news, legislation, publications and links.

ARTCC – Air Route Traffic Control Center. Provides air traffic separation and flight follwoing services for aircraft outside the terminal areas. (Generally, en route traffic)

ASAP – Aviation Safety Action Program. (FAA) The objective of the ASAP is to encourage air carrier and repair station employees to voluntarily report safety information that may be critical to identifying potential precursors to accidents. A non-punitive self-reporting system, equivalent to a company-specific ASRS program.

ASAS – Aviation Safety Analysis System. A component of a Safety Management System (SMS)

asBAA – Asian Buiness Aviation Association.

ASRS – Aviation Safety Reporting System. A non-punitive means for pilots, flight attendants, mechanics, air traffic controllers and others in the aviation community to report observed safety concerns.

ASHP – Aviation Safety and Health Program (FAA/OSHA). The joint FAA/OSHA Aviation Safety and Health Team was formed to identify the factors to be considered in determining whether OSHA requirements can be applied to the working conditions of employees on aircraft in operation (other than flight deck crew) without compromising aviation safety.

ATA – Air Transportation Association of America.

ATC – Air Traffic Control.

ATIS – Automated Terminal Information Service. A taped broadcast of airport conditions, weather, runway(s) in use, and notes to flight crews. Generally updated hourly.

ATOS – Air Transportation Oversight Program (FAA). The Federal Aviation Administration’s primary tool for overseeing the airlines.

ATPL – Airline Transport Pilot License

ATS – Air Traffic Service. The international equivalent of ATC.

AvWeb – An on line business aviation news site.

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BASA – Bilateral Aviation Safety Agreement. Under BASA, the FAA oversees the 1,237 EASA-certified repair facilities in the U.S. and EASA does the same for the 425 FAA-certified repair stations in Europe.

BBGA – British Business and General Aviation Association

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C of A – Certificate of Airworthiness

C of C – Certificate of Conformance

C of R – Certificate of Registration

CBAA – Canadian Business Aviation Association.

CADIZ – Canadian Air Defense Identification Zone.

CAM – Certified Aviation Manager (NBAA certification program).

CAME – Continuing Airworthiness management Exposition

CAMTS – Commission on Accreditation of Medical Transport Services. An industry organization for setting and auditing standards in the EMS community, both airplane and helicopter.

CAMO – Continuing Airworthiness management Organization

CAT – Clear Air Turbulence.

CAT-II – Category Two approach. A precision instrument approach with a Decision Height lower than 200 feet above the Touchdown Zone but not lower than 100 feet. Requires special aircraft and air crew certification.

CBAA – Canadian Business Aviation Association

CDI – Course Deviation Indicator

CFI – Certificated Flight Instructor.

CFII – Certificated Flight Instructor – Instrument (a “CF double – I”).

CFIT – Controlled Flight Into Terrain. A type of aviation accident in which the aircraft, seemingly stable and in complete control of the crew, impacts terrain, water, or an obstacle.

CHDO – Certificate Holding District Office. (FAA) The Flight Standards District Office (FSDO) or Certificate Management Office (CMO) having overall responsibility for all FAA reporting requirements, technical administration requirements, and regulatory oversight of a certificate holder.

CRM – Cockpit Resource Management or Crew Resource Management. A training concept and standard practice by which the flight crew functions and communicates as part of a team, as opposed to individual pilots, flight attendants, maintenance technicians, etc.

CASS – Corporate Aviation Safety Seminar (produced annually by the Flight Safety Foundation).

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DA – Density Altitude. Altitude above sea level, adjusted to account for the effects of variations in atmospheric pressure and temperature. Useful in the prediction of aircraft performance.

DME – Distance Measuring Equipment. The time for a signal transmitted from an aircraft to a ground station and return is a measure of the aircraft’s distance from that station.

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EAA – Experimental Aircraft Association.

EASA – European Aviation Safety Agency. The equivalent of the FAA for the European Union.

EBACE – European Business Aviation Convention & Exhibition. An annual event sponsored by the NBAA.

EFB – Electronic Flight Bag. A device, either portable or mounted in the aircraft, used to provide navigation planning information to the flight crew. meant to replace paper charts.

EGPWS – Enhanced Ground Proximity Warning System. Next generation ground proximity warning, based on a world-wide database of known terrain features and obstructions.

ELT – Emergency Locator Transmitter. Activated by g-forces in an aircraft accident, the ELT emits a signal useful in tracking the location of the accident.

ENG – Electronic News Gathering. A commercial use of aircraft.

EAPIS – Electronic Advance Passenger Information System. Administered by the U.S. Bureau of Customs and Border Protection, this system is used to send passenger manifest to CBP prior to departure on an international flight (either outgoing or incoming.)

EPAis – Environmental Protection Agency international standards (refers to ICAO CO2 limits from aircraft engines)

ERAM – EnRoute Automation Modernization. The FAA’s plan for replacing computers and other electronic devices in the nation’s Air Route Traffic Control Centers.

ERC – Event Reivew Committee (FAA). The group reviews and analyzes reports submitted under an ASAP. The ERC may share and exchange information and identify actual or potential safety problems from the information contained in the reports. The ERC is usually comprised of a management representative from the certificate holder, a representative from the employee labor association (if applicable), and a specifically qualified FAA inspector.

ERP – Emergency Response Plan

ERS – Emergency Response Services

EVS – Enhanced Vision System. Uses infrared or microwave radar for a pilot to “see” ahead of the aircraft in reduced visibility conditions.

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FAA – Federal Aviation Administration of the USA

FAR – Federal Aviation Regulation.

FATO – Final Approach and Take-off Area

FBO – Fixed Base Operator. An aircraft service provider. Typically fuel and hangaring but may also provide maintenance and parts support.

FDAP – Flight Data Analysis Program (an ICAO requirement)

FIR – Flight Information Region

FL – Flight Level. An assigned altitude at which all aircraft use a standard altimeter setting of 29.92 inches.

FMS – Flight Management System. The central nervous system of a modern aircraft. It contains navigation systems, aircraft monitoring systems, flight control systems, and information systems used to operate the aircraft.

FOD – Foreign Object Damage. Damage to a turbine engine caused by ingestion of an object that is not part of the engine. Example: Ingestion of a rock or a bird.

FOM – Flight Operations Manual.

FOQA – Flight Operations Quality Assurance. (FAA) A voluntary safety program designed to improve aviation safety through the proactive use of flight-recorded data.

FSDO – Flight Standards District Office (FAA).

FSF – Flight Safety Foundation. A non-profit international organization dedicated to aviation safety.

FSI – FlightSafety International. A provider of aviation simulator-based training.

FTD – Flight Training Device. Designated in six levels of increasing complexity and capability, levels 1-6. Also, an FTD is more generic than a flight simulator, which by definition must replicate a particular aircraft model.

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GM – Guidance Material

GOM – General Operating Manual.

GPS – Global Positioning System (U.S. nomenclature) Several similar satellite systems launched by different countries have distinct names. Generically called GNSS, Global Navigation Satellite System.

GPWS – Ground Proximity Warning System. Older technology version of EGPWS.

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HAI – Helicopter Association International

HAI – High Altitude Indoctrination

HEMS – Helicopter Emergency Medical Services.

HOTAS – Hands On Throttle And Stick. Numerous buttons and switches on the throttle and control stick used to control communication and navigation modes and cursors.

HUD – Heads Up Display. Also called HUG, Head Up Guidance.

HUMS – Health and Usage Monitoring System (Electronic aircraft maintenance assist tool, used primarily on helicopters.)

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IA (interchangeably AI) – Inspection Authorization/ Authorized Inspector (maintenance).

IASA – International Aviation Safety Assessments. (FAA) Foreign assessment program focused on a country’s ability, not the individual air carrier, to adhere to international standards and recommended practices for aircraft operations and maintenance established by the United Nation’s technical agency for aviation, the International Civil Aviation Organization (ICAO).

IASA – Insurance Accounting & Assistance Association.

IATA – International Air Transportation Association. An international trade body, created some 60 years ago by a group of airlines. Today, IATA represents some 230 airlines comprising 93% of scheduled international air traffic.

IBAC – International Business Aviation Council. The association of aviation associations. NBAA is a member, as is CBAA, EBAA, and 12 other associations. IBAC is the originator of the International Standard for Business Aircraft Operations, IS-BAO.

ICAO – (UN) International Civil Aviation Organization. The International Civil Aviation Organization, a UN Specialized Agency, is the global forum for civil aviation. ICAO works to achieve its vision of safe, secure and sustainable development of civil aviation through cooperation amongst its member states.

IFR – Instrument Flight Rules (refers to Federal Aviation Regulations).

IHST – International Helicopter Safety Team. Understanding that helicopter accident trends were not improving, that the market place is adversely affected by such trends and that new analysis methods were available to improve safety, the IHST was formed and the JHSAT was chartered to develop data-driven safety recommendations that would be used to pursue the goal of reducing helicopter accidents by 80% by 2015.

IIMC – Inadvertent Instrument Meteorological Conditions (unintentional flight into weather that requires instrument flight training and equipment)

IMC – Instrument Metrological conditions (refers to weather).

IS-BAO – International Standard for Business Aircraft Operations. A total system for managing a flight department/charter operation that includes Safety Management System.

ISO – International Standards Association

IOSA- IATA Operational Safety Audit.

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JAA – Joint Aviation Authority of the European Union

JAR OPS – Joint Aviation Regulations – Operations

JAR -FCL – Join Aviation Regulation – Flight Crew Licensing

JHSAT – Joint Helicopter Safety Applications Team. A part of the IHST that is charged with developing new safety applications.

JHSIT – Joint Helicopter Safety Implementation Team. A part of the IHST that is charged with developing methods to implement new safety applications.



LNAV – Lateral Navigation. A subset of RNAV. An LNAV instrument approach provides no descent guidance.

LZ – Landing Zone.

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MEL – Minimum Equipment List

MFD – Multi Function Display. It may stand alone in the cockpit or be part of the Flight Management System. So named because the MFD can present a selection of types of information to the flight crew – real time weather information, navigation charts, moving map display, aircraft performance data, airport information, etc.

MM – Make & Model (as a sub set of total flight time).

MMEL – Master Minimum Equipment List. A generic listing applicable to a particular model aircraft, advising the crew or maintenance technician what equipment may be inoperable under stated conditions and still consider the aircraft to be airworthy. Part 91 operators may use an MMEL for reference; Part 135 operators must have an aircraft-specific MEL for the same purpose.

MNPS – Minimum Navigation Performance Specification

MTOW – Maximum Takeoff Weight.

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NAS – National Airspace System (FAA). All inclusive term for U.S. controlled airspace, air traffic control, equipment and procedures.

NAT – North Atlantic

NATA – National Air Transportation Association.

NBAA – National Business Aviation Association.

NDB – Non-Directional Beacon (ground based navigation equipment).

NEMSPA – National EMS Pilots Association.

NPRM – Notice of Proposed Rulemaking (Federal requirement to provide notice prior to enacting a new regulation)

NORAD – North American Aerospace Defense Command.

NOTAM – Notice to Airmen

NVG – Night Vision Goggles.

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OCAS – Obstacle Collision Avoidance System. A radar is installed on the obstacle. When an aircraft is detected by the radar, a radio signal is sent to alert the approaching aircraft.

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PAMA – Professional Aviation Maintenance Association.

PAPI – Precision Approach Path Indicator.

PBN – Performance Based Navigation

PF – Pilot Flying

PIC – Pilot In Command. Holds the ultimate authority and responsibility for the operation and safety of a particular flight.

PIO – Pilot Induced Oscillation.

PFD – Primary Flight Display (aircraft avionics). Displays primary flight information to the crew, i.e. aircraft attitude, altitude and speed, navigation references, etc.

PM – Pilot Monitoring

PNF – Pilot Not Flying

PPC – Pilot Proficiency Check

PPE – Personal Protection Equipment. Safety glasses and earplugs are examples.

PRM – Precision runway monitor

PTS – Practical Test Standards. The standards to which a pilot is held during a flight check leading to a new certification or rating.

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QFE – Height above airport or runway, local station pressure

QNH – Altitude above mean sea level, local station pressure


RAIM – Receiver Autonomous Integrity Monitoring

RIMS – The Risk Management Society

RNAV – Area Navigation

RNP – Required Navigation Performance. Assigned to some air navigation routes and procedures, requiring the aircraft and crew to be certified able to operate within the stated standard, e.g. RNP 1 means the aircraft must be within 1 nm of the course centerline.

RPAS – Remotely Piloted Aircraft Systems

RVSM – Reduced Vertical Separation Minima. Requires certification of aircraft and crew for operation above FL 290 (in most jurisdictions).

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SAFO – Safety Alert For Operators. Issued by the FAA when necessary. Provides information and guidance for conditions that have been cause for concern among users of the NAS.

SAI – Safety Attribute Inspection (FAA).

SAR – Search and Rescue

SAS – Safety Assurance System (FAA).

SASO – System Approach for Safety Oversight (FAA).

SBT – Scenario Based Training. Puts the training pilot in realistic flight situations, as opposed to repeatedly practicing the same flight maneuvers.

SDR – Standard Drawing Rights (monetary measure). An international monetary leveling system used by the World Bank to coordinate currency equivalents.

SDR – Service Difficulty Report (maintenance). Submitted to an FAA central databank to advise operators and maintenance technicians of an observed condition that warrants attention.

SIC – Second In Command of an aircraft. Copilot.

SID – Standard Instrument Departure

SLOP – Strategic Lateral Offset Procedure. Used by air crews over international waters to avoid wake turbulence when closely following other aircraft.

SMS – Safety Management System.

SOP – Standard Operating Procedures.

SPOT – Safety Promotion Outreach Team. An international FAA group tasked with preparing the FAA workforce for system changes by sharing information with the field on SASO, SMS and SAS.

SRM – Single-pilot Resource Management.

STAR – Standard Arrival Route

SVS – Synthetic Vision System. A visual picture outside the cockpit, constructed electronically and presented to the flight crew to aid in situational awareness.

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TAA – Technologically Advanced Aircraft. Minimally contains a moving map display and an integrated autopilot. Generally refers to the new generation glass cockpit of single engine and multi-engine piston aircraft.

TAWS – Terrain Awareness and Warning Systems.

TCAS –Traffic Alert and Collision Avoidance System. Based on the receipt of another aircraft’s transponder signal, including altitude information. TCAS-I advises the crew of traffic in their vicinity, including relative altitude. TCAS-II provides the same information and adds a Resolution Advisory (RA) in terms of climb or descend to avoid that traffic.

TEM – Threat and Error Management. A training concept and standard practice that helps the flight crew recognize potential threats to safety of their flight or errors made by the flight crew of others, giving the crew the opportunity to manage those threats and errors.

TR – Type Rating

TT – Total Time. Used interchangeably with Total Logged Flight Hours, although not necessarily the same.

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UAS – Unmanned Aerial System.

UAV – Unmanned Aerial Vehicle. (a pilotless “drone”).

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VDRP – Voluntary Disclosure Reporting Program (part of a SMS).

VFR – Visual Flight Rules (refers to Federal Aviation Regulations).

VLJ – Very Light Jet

VMC – Visual Metrological Conditions (refers to weather).

VNAV – Vertical Navigation. A type of RNAV approach that includes advisory descent guidance. Requires specialized avionics installation.

VOR – VHF Omni Range, ground-based radio navigation signal.

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WAAS – Wide Area Augmentation System (upgrade to GPS). A signal sent to correct inherent errors in the transmission of GPS signals (due to atmospheric conditions, etc.) WAAS improves accuracy of the aircraft’s derived position, allowing greater precision in instrument approach procedures.

WX – Weather.

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