Aviation Acronyms

We use a lot of acronyms in aviation. It almost sounds like a completely different language. If you’re new to aviation acronyms (or just want to know the meaning of that acronym you use all the time!), you’ve come to the right place.

We’ve categorized hundreds of aviation acronyms below. To find the acronym you need to know, either use the search function or review the entire list, grouped by category.   

Aircraft Part Conditions /Types of Aircraft Parts

AcronymFull TitleDefinition
ARAs RemovedThe part is in the same condition as when it was removed from the aircraft
BERBeyond Economical RepairThe cost to repair or overhaul the part exceeds the part’s value
EXPExpiredThe aircraft part has exceeded its limit or shelf life
FNFactory NewThe aircraft part is brand new from the manufacturer
FTFunction TestedThe aircraft part has gone through a required inspection/evaluation process to prove it is functional
INInspectedThe aircraft part has been visually inspected after removal from the aircraft to determine serviceability
LLPLife Limited PartThe aircraft part has a mandatory replacement limit
MDModifiedThe aircraft part has been modified from its original configuration
NENewThe aircraft part has never been used and has no operating time or cycles
NSNew SurplusThe aircraft part has gone through one or more sellers but has never been used and has no operating time or cycles
OHOverhauledThe aircraft part has been refurbished to applicable standards
RBRebuiltThe aircraft part has been disassembled, inspected, repaired as necessary, reassembled, tested, and approved to the same tolerances and limits as a new part
RJRejectedThe aircraft part is rejected because it is unrepairable or the repair cost is not economical
RP/REPRepairedThe aircraft part was restored to airworthy condition
SVServiceableThe aircraft part is deemed airworthy and ready to return to service

At the Airport

AcronymFull TitleDefinition
AFLAirfield LightingA lighting system that supports pilots during take-off, landing, and taxi
ALSApproach Lighting SystemLights that extend from the end of the runway
ATCAir Traffic ControlPersonnel who authorize and control commercial aircraft on the ground and in flight
FOD Foreign Object Debris Objects that interfere with or get too close to an aircraft or personnel, resulting in damage or injury


AcronymFull TitleDefinition
ACARSAircraft Communication, Addressing, and Reporting SystemA digital datalink system for transmitting routine reports and messages between the aircraft and ground stations
ACASAirborne Collision Avoidance SystemAn airborne system for alerting pilots of the presence of other aircraft nearby and the possibility of a mid-air collision. Also known as Traffic Alert and Collision Avoidance System (TCAS)
ACLSAutomatic Carrier Landing SystemA system that assists aircraft when landing on an aircraft carrier by providing automatic control of flight path and approach velocity
ADAHRSAir Data Attitude Heading Reference SystemProvides air data information as well as attitude and heading to the flight deck instruments
ADSAutomatic Dependent SurveillanceA surveillance technique used by aircraft that automatically provides data from onboard navigation and position-fixing systems
ADS-AAutomatic Dependent Surveillance AddressAutomated transmission of location information for aircraft using an airline-specified communication system
ADS-BAutomatic Dependent Surveillance-BroadcastA surveillance technique that determines the aircraft’s position via satellite navigation or other sensors
ADS-CAutomatic Dependent Surveillance ContractA surveillance technique where data is transmitted between the ground system and the aircraft via a datalink contract with a provider network
AFCSAutomatic Flight Control SystemA system that integrates autopilot, related flight director systems, and attitude heading reference system (AHRS)
For Aircraft Flight Control System (AFCS), see Cockpit/Flight Deck section
AHRSAttitude Heading Reference SystemAn inertial sensor comprised of an IMU and another sensor used for heading and attitude determination
ANSPAir Navigation Service ProviderAn organization providing Air Navigation Services by managing air traffic for a company, region, or country.
ATNAeronautical Telecommunications NetworkAn internetwork architecture that provides ground/ground, air/ground, and avionic data subnetworks for using ISO OSI Reference Model interface services and protocols
B RNAVBasic Area NavigationA method of instrument flight rules navigation that allows an aircraft to choose a course within a network of navigation beacons
CMSCabin Management SystemAn interface that allows crew and passengers to control various cabin functions, such as lighting, climate, and entertainment systems
CNS/ATMCommunication, Navigation, and Surveillance / Air Traffic ManagementThe main functions forming the air traffic management infrastructure to ensure safe and efficient air travel
CPDLCController-Pilot Data Link CommunicationsAn aircraft traffic control (ATC) communication system between controller and pilot using datalink (same as ADS-C)
CVRCockpit Voice RecorderA recording device for recording radio transmissions and sounds in the cockpit
DFDRDigital Flight Data RecorderA system used for recording and storing data from sensors mounted throughout the aircraft avionics and flight control systems
DLRDatalink RecorderDLR system records CPDLC messages for each data link type (typically a digital type CVR)
EAFAP Engineering Assisted Field Approval Process A document put out by Universal Avionics authorizing approved dealers to install their FMS/LPV systems on aircraft approved within specific guidelines
EFISElectronic Flight Instrument SystemA flight deck instrument display system in which the display technology used is electronic rather than electromechanical. EFIS systems portray information using cathode ray (CRT) or liquid-crystal display (LCD) technology. EFIS consists of PFD, MFD, and EICAS (see Cockpit/Flight Deck section)
EGNOSEuropean Geostationary Navigation Overlay ServiceA satellite-based augmentation system used to improve GPS performance in European Airspace
EGPWSEnhanced Ground Proximity Warning SystemA system that alerts pilots if they are flying at an excessive rate for the aircraft’s location (i.e., approaching the ground, obstacle, or water’s surface)
ELTEmergency Locator TransmitterAn independent transmitter that broadcasts signals to determine the location of aircraft activated by excessive G-forces
EVSEnhanced Vision SystemA system that provides information from aircraft sensors during limited visibility environments. Also known as cockpit heads up display (HUD)
FANS-1/AFuture Air Navigation System 1/A (developed by Airbus)A system providing direct data link communication between pilot and air traffic controller for clearances, pilot requests, and reporting aircraft position primarily over water
FDAUFlight Data Acquisition UnitA unit for receiving various forms of data from sensors and avionics systems and routing them to the flight data recorder (FDR) or quick access recorder (QAR)
FDRFlight Data RecorderA device used to record aircraft performance parameters to be reviewed in case of an accident
FIDSFlight Information Display SystemA computer system that displays flight information (arrivals/departures) to passengers at an airport
FMSFlight Management SystemA computer on board the aircraft provides virtual data for navigation, performance, and aircraft operations. The FMS is a specialized computer system that automates a wide variety of in-flight tasks, reducing the workload on the flight crew
GAGANGPS-Aided Geo-Augmentation NavigationAn augmentation system implemented in India that uses GPS constellation and adds accuracy and integrity
IFEIn-Flight EntertainmentAn onboard entertainment system that provides passengers with access to Wi-Fi, movies, TV, and/or music
ILSInstrument Landing SystemA precision radio navigation system for providing vertical and lateral runway approach
For Inventory Locator System (ILS), see Selling and Returning Aircraft and Parts section
INSInertial Navigation SystemA navigation system used to track an object’s position and orientation relative to a known starting point
IRSInertial Reference SystemA system providing safety critical position and precise attitude and heading, and is a key component of the aircraft’s inertial navigation system (INS)
LNAV Lateral Navigation A non-precision instrument approach included in RNAV and is often combined with VNAV
LP Localizer Performance A non-precision landing approach for WAAS lateral guidance
LPVLocalizer Performance with Vertical GuidanceA precise landing approach using an SBAS/WAAS-enabled system that is more accurate than the instrument landing system (ILS)
MSASMulti-functional Satellite with Vertical GuidanceA Japanese satellite-based augmentation system (SBAS) using GPS augmentation to improve accuracy, integrity, and availability
PBNPerformance- Based NavigationOne of several enablers for implementing global standardization of RNAV and RNP, changing an aircraft’s required navigation capability from sensor-based to performance-based
REURemote Electronics UnitsElectronics located on or near the actuator to control the actuator
RNAVArea NavigationA navigation method that allows operators to choose any flight course within a network of navigation beacons
QARQuick Access RecorderAn airborne flight recorder for providing access to flight data through cellular networks and/or memory cards
SBASSatellite-Based Augmentation SystemAn augmentation system using geostationary satellites to provide integrity assurance and increased accuracy
TAWSTerrain Awareness and Warning SystemA warning system that alerts pilots that they are flying in potentially hazardous proximity to terrain
TCASTraffic Alert and Collision Avoidance SystemSee ACAS
VNAVVertical Navigation VNAV provides glidepath information during an instrument approach
WAASWide Area Augmentation SystemAn accurate air navigation system developed by the FAA for improved accuracy, integrity, reliability, and availability, using global positioning and geostationary satellites


AcronymFull TitleDefinition
Ni-Cd / NiCadNickel CadmiumBatteries made of nickel-cadmium cells that contain interleaved electrodes and a separator system with a gas barrier
SLASealed Lead AcidBatteries that are best known as being maintenance-free and spill-proof


AcronymFull TitleDefinition
COC /CofCCertificate of ConformanceA certificate stating that an aeronautical product meets required standards or specifications
CRSCertificate of Release to ServiceA certificate demonstrating that a task has been verified and signed by authorized personnel (this certificate is not a statement of airworthiness)
ISOInternational Organization for StandardizationAn international organization that sets and standardizes measurements for industrial, commercial, and scientific purposes
STCSupplemental Type CertificateA type certificate (TC) denoting civil aviation authority approval for modification or major repair of an aeronautical product on an existing type certified aircraft, engine, or propeller
TCType CertificateA certificate for a particular type of aircraft signifying airworthiness
For Total Cycles (TC), see Cycles and Times section
For Transport Canada (TC), see Regulation Authorities section

Cockpit / Flight Deck

AcronymFull TitleDefinition
ADCAir Data ComputerA computer that determines various aircraft information such as calibrated airspeed, Mach number, and altitude/altitude trend
ADFAutomatic Direction FinderAvionics used for en-route navigation and approach procedures
ADIAttitude Direction IndicatorA computer that receives and processes information from the aircraft’s navigation system (a.k.a. FDI)
AFCSAircraft Flight Control SystemA conventional fixed-wing system that consists of flight control surfaces, cockpit controls, connecting linkages, and other operating mechanisms that control flight direction
For Automatic Flight Control System (AFCS), see Avionics section
Aircraft Flight Manual
A physical or electronic book containing the information required to operate a specific aircraft. Every aircraft has its own AFM
Aircraft Flight Manual Supplement A chapter within the Aircraft Flight Manual (AFM)
CDICourse Deviation IndicatorAn instrument used to determine an aircraft’s lateral position as it relates to a radio navigation beacon
CDSCockpit Display SystemA system that provides the human machine interface (HMI) that allows the crew to manage the cockpit and interact with the avionic systems
CDUControl Display UnitA computer interface for accessing flight management computers (FMC) and other aircraft computers
EFDElectronic Flight DisplaysA cockpit display consisting of electronic instruments; commonly known as a “glass cockpit”
EICASEngine Indicating and Crew Alerting SystemsA system that provides flight crews with instrumentation regarding the engines, such as speed of rotation, temperature, etc., and alerting the crew in case of system failure
FCUFlight Control UnitA display unit used for automatic flight controls, such as the flight management guidance system (FMGS)
For Fuel Control Unit (FCU), see Fuel section
FDIFlight Director IndicatorSee ADI
FMCFlight Management ComputersThe computer component of the flight management system (FMS; see Avionics)
FMGSFlight Management Guidance SystemA system that provides flight time, mileage, speed, and altitude predictions
HMIHuman Machine InterfaceHardware or software that allows the operator to contact a controller
HSIHorizontal Situation IndicatorA flight instrument is used in place of a conventional heading indicator and is generally mounted under the artificial horizon
For Hot Section Inspection (HSI) see Cycles and Time section
ISISIntegrated Standby Instrument SystemAn electronic instrument to serve as a backup in case of standard glass cockpit instrumentation failure
MCPMode Control PanelAn instrument panel that controls advanced autopilot (usually in commercial jets)
MEAMinimum En route AltitudeThe lowest published altitude for navigation signal coverage and obstacle clearance requirements between radio fixes
MFDMulti-Function DisplayA screen that displays the aircraft’s navigational route, information about the aircraft (e.g., engine, hull, etc.), and other systems, such as a moving map, weather radar, and warning systems (e.g., TCAS)
NDNavigation DisplayA cockpit instrument that provides pilots with navigational and weather information and situational awareness
PFDPrimary Flight DisplayA flight deck instrument where the pilot’s primary flight information is displayed
POHPilot’s Operating Handbook An official rule book containing operating information that has been issued for that specific serial number aircraft
RMIRadio-Magnetic IndicatorAn electronic navigation instrument used to show the magnetic heading the aircraft is flying (acts as a compass) that works in conjunction with the automatic direction finder (ADF) or very high omnidirectional range (VOR)
RMURadio Management UnitThe primary interface for controlling radio system functions
RTURadio Tuning UnitA panel-mounted unit for centralized control of radio frequencies and operating modes
VORVery High Omnidirectional RangeA ground-based system providing navigational aid

Cycles and Time

AcronymFull TitleDefinition
CRCycles RemainingNumber of cycles remaining on an aircraft part before replacement or overhauled
CSLSVCycles Since Last Shop VisitNumber of cycles tracked from the last shop visit for an aircraft part
CSNCycles Since NewNumber of cycles since the aircraft part was manufactured
CSOCycles Since OverhaulNumber of cycles since the aircraft part was overhauled
CZICore Zone InspectionThis is an inspection conducted on a turbofan engine
HSIHot Section InspectionThis is an inspection of several key engine components. The inspection is conducted at the recommended interval for the particular engine
For Horizontal Situation Indicator (HSI), see Cockpit/Flight Deck section
LSVLast Shop VisitLSV refers to a date, indicating when an aircraft part was last serviced
TCTotal CyclesTC is the number of cycles an aircraft part has accrued
For Type Certificate (TC), see Certificates section
For Transport Canada (TC), see Regulation Authorities section
TRTime RemainingTR may refer to either the amount of time remaining on an aircraft part before its next inspection or the amount of time remaining on an aircraft part’s serviceable life (time may be calculated in flight hours or calendar time)
For Thrust Reverser (TR), see Wings and Leading Edges section
TSLSVTime Since Last Shop VisitThe amount of time on an aircraft part since the last shop visit
TSNTime Since NewThe amount of time since the aircraft part was manufactured
TSO / TTSOTime Since Overhaul / Total Time Since OverhaulThe amount of time since the aircraft part was overhauled
For Technical Standard Order (TSO), see Maintenance section
TSRTime Since RepairThe amount of time since the aircraft part was repaired
For Technical Service Representative (TSR), see Maintenance
TTTotal TimeTT is the total amount of time (typically in flight hours) that an aircraft part has operated

Engines and Generators

AcronymFull TitleDefinition
ADGAir Driven GeneratorA small wind turbine attached to an aircraft to be used as a power source (a.k.a. Ram Air Turbine; see RAT)
APUAuxiliary Power UnitAPUs support the aircraft’s main engine and provide emergency power
ECUEngine Control UnitA device that controls multiple systems within the aircraft engine (a.k.a., EEC)
EECElectronic Engine ControllerSee ECU
DEECDigital Electronic Engine ControlA component that combines numerous engines to improve engine life and performance
FADECFull Authority Digital Engine ControlA system that consists of an electronic control unit (ECU) for controlling all aspects of the aircraft engine
IDGIntegrated Drive GeneratorA power system that controls the engine’s hydraulic systems
GCUGenerator Control UnitA device that controls and monitors generator operations and voltage regulations; it is commonly found on turboprop aircraft
ITTInterstage Turbine TemperatureA way of measuring combustion gas temperatures during compressor and turbine stages in turbofan engines
PDUPower Distribution UnitA unit that connects, transfers, and distributes electrical power to the aircraft loads and protects the aircraft’s power systems and electronic devices
For Power Drive Unit (PDU), see below
PDUPower Drive UnitA unit used to create mechanical motion from electrical or hydraulic power. It is used to drive the mechanical actuation system
For Power Distribution Unit (PDU), see above
PRSOVPressure Regulating and Shut-Off ValveA system that regulates bleed air pressure and shuts off the air supply from the engine if a failure in the bleed system is detected
RATRam Air TurbineSee ADG

Flight / Flying

AcronymFull TitleDefinition
AGLAbove Ground LevelThe aircraft’s altitude above ground level in feet
FIKIFlight Into Known IcingFIKI is when an aircraft flies into atmospheric conditions where ice may be present
MSLMean Sea LevelThe aircraft’s altitude above standardized sea level


AcronymFull TitleDefinition
FCUFuel Control UnitA hydro-mechanic device to control the flow of fuel; a.k.a. a fuel management unit (FMU)
For Flight Control Unit (FCU), see Cockpit/Flight Deck section
FMUFuel Management UnitSee FCU (Fuel section)
SAFSustainable Aviation FuelA more environmentally friendly fuel option


AcronymFull TitleDefinition
AMMAircraft Maintenance ManualA formal document that describes how to conduct maintenance on a particular aircraft
AOGAircraft on GroundAn aircraft with an issue that prevents it from flying
ATAAir Transport AssociationATA codes (a.k.a ATA Chapters or ATA 100 System Codes) categorize aircraft parts and systems in the Component Maintenance Manual (CMM), Aircraft Maintenance Manual (AMM), and Illustrated Part Catalog (IPC)
A&PAirframe and Powerplant (mechanic)A licensed aircraft mechanic
A/C HRSAircraft HoursThis refers to the total number of aircraft hours (since birth) or the number of hours between scheduled maintenance
BCBench CheckA series of inspections and tests are performed on an aircraft part to determine its serviceability
CAMO Continuing Airworthiness Management OrganizationA civil aviation organization authorized to schedule and control activities to ensure continued airworthiness on aircraft and aircraft parts
CMMComponent Maintenance ManualA formal document that describes how to conduct off-aircraft maintenance
CPCPCorrosion Prevention and Control ProgramA program that maintains aircraft from corrosion based on the aircraft’s systematic interaction with chemicals and the environment
C/WComplied WithShorthand for “complied with”
DERDesignated Engineering Representative A person with an engineering degree or equivalent who is appointed under 14 CFR section 183.29 to ensure that engineering data complies with appropriate airworthiness standards
DOMDirector of MaintenanceA person who directs aircraft maintenance, including overseeing maintenance, identifying requirements, and forecasting resources in a timely manner
DVIDetailed Visual InspectionAn inspection used in cases of attempted defect rectifications and proactive maintenance requirements
EPSUEmergency Power Supply UnitAn emergency system in case one of the main power supplies fails; a.k.a. emergency power unit (EPU)
EPUEmergency Power UnitSee EPSU
EWISElectrical Wire Interconnection SystemA system of wires, wiring devices, termination devices, or any combination of all three that is installed in any area of the aircraft
FBOFixed-Base OperatorA commercial enterprise that has been authorized to provide aviation services at an airport
H/STABHorizontal StabilizerThe stationary, horizontal part of an aircraft’s airfoils
ICAInstructions for Continued AirworthinessA document specifying the maintenance data for the continued airworthiness of a part produced by the design approval holder
IPCInstrument Proficiency CheckAn instrument rating review to demonstrate competency in the instrument approaches
For Illustrated Parts Catalog (IPC), see Selling and Returning Aircraft and Parts section
LLRULower Line Replacement UnitA modular aircraft component (sealed unit with identifiable part number and tracking information) that can be replaced quickly at an operating location (a.k.a. LRC, LRI, LRU)
LRCLine Replacement ComponentSee LLRU
LRILine Replacement ItemSee LLRU
LRULine Replacement UnitSee LLRU
MRO Maintenance, Repair, OverhaulA facility where aircraft maintenance, repair, and overhaul are performed
NDTNon-Destructive TestingA process for testing aircraft parts to locate potential damage without dismantling or damaging the parts
RTSReturn to ServiceWhen an aircraft is allowed to resume operation after maintenance
SRMStructural Repair ManualA manual that specifies procedures for minor structural damage to aircraft
TATTurnaround TimeThis refers to the amount of time between landing and the next flight or the length of time for scheduled maintenance or repair of parts or components
TSRTechnical Service RepresentativeThis person is the main point of contact during aircraft maintenance
For Time Since Repair (TSR), see Times and Cycles section
TSOTechnical Standard OrderAn order specifying the minimum performance standard to which a specific aircraft part must comply
For Time Since Overhaul (TSO), see Cycles and Times section


AcronymFull TitleDefinition
ACAdvisory CircularIssued by regulatory authorities (e.g., FAA), ACs specify how to comply with airworthiness regulations, pilot certifications, and any other airworthiness standards
ADAirworthiness DirectiveIssued by regulatory authorities (e.g., FAA), ADs are legally enforceable under 14 CFR Part 39 and may be accompanied by SBs. Changes or upgrades are critical for aircraft safety
CMRCertificate of Maintenance ReviewCMRs are issued at intervals in accordance with the approved Maintenance Programme for an aircraft
SBService BulletinSBs are issued by the OEM and describe possible (or required) changes to their aeronautical products

Parts of Aircraft

AcronymFull TitleDefinition
ACMAir Cycle MachineA refrigeration unit for the environmental control system (ECS)
A/CAircraftAbbreviation for “Aircraft”
ECSEnvironmental Control SystemA system that provides aircraft occupants with air supply, thermal control, and cabin pressurization
IPSIce Protection SystemThis system either prevents ice from forming on aircraft or removing ice that has formed
LCVLoad Control ValveA valve that is commonly installed on the aircraft’s auxiliary power unit (APU)
MEDMain Entrance DoorThe primary door for entrance to the aircraft
MLGMain Landing GearThe landing gear located under the main fuselage of the aircraft
MLG DBMain Landing Gear Drag BraceThe brace supports the landing gear and keeps it from collapsing when lowered while still allowing the landing gear to retract
MLG SSMain Landing Gear Shock StrutThe struts are used to absorb and dissipate shock loads when the aircraft lands
MWAMain Wheel AssemblyWheel assembly attached to the main landing gear that is connected to the aircraft’s braking system
NLGNose Landing GearThe landing gear is located under the nose of the aircraft
NWANose Wheel AssemblyWheel assembly attached to the nose landing gear
PBEProtective Breathing EquipmentSafety equipment that provides oxygen for crewmembers
PCBPrinted Circuit BoardCircuit boards that have been printed and may be used on aircraft components
PSEUProximity Sensor Electronic UnitA system that communicates the state of system components (e.g., doors, flaps, etc.) to other aircraft systems (such as warning systems)
RCDIRate of Climb and Descent IndicatorAn instrument that indicates climb or descent rate; a.k.a. a vertical speed indicator (VSI)
RVSMReduced Vertical Separation MinimumThis system ensures that aircraft keep a minimum distance apart from each other in flight
SCUSelf-Contained UnitProtective breathing devices (or smoke hood) that is lightweight and self-contained
ULBUnderwater Locator BeaconA device that is activated once submerged in water that transmits an ultrasonic signal; a.k.a. an underwater locating device (ULD)
ULDUnderwater Locating DeviceSee ULB
W/SWindshieldThe front window on the aircraft, commonly referred to as a windscreen
XCVRTransceiverAn electronic device for backup communication and navigation
XMTransmitterAn electronic device for broadcasting at designated radio frequencies

Selling and Returning Aircraft Parts

AcronymFull TitleDefinition
B2B/BTBBack to BirthA trace document that describes either “broken” or “unbroken” trace information. “Broken” is a partial trace list that may only include the aircraft part’s times and cycles since overhaul. “Unbroken” is the document showing the complete history of the part from when it was first manufactured
BASABilateral Aviation Safety AgreementAn agreement between two countries to accept civil aviation certifications, ensuring that an imported aircraft part from one country will be accepted and installed on an aircraft in another country
CODCash on DeliveryPayment is made at the time the product is delivered (or the service is rendered)
DGDangerous GoodsProducts that may contain a material or substance that poses a health risk or safety issue; for example, HAZMAT
EDDEstimated Delivery DateThe anticipated date of delivery for a shipment
EUSEnd Use/User StatementA document certifying that a buyer is the final recipient and will not be exporting the shipment to someone else
HAZMATHazardous MaterialsMaterial deemed as posing a threat to a person’s health or safety
ILSInventory Locator SystemA system for locating available aircraft parts inventory.
For Instrument Landing System (ILS), see Avionics section
IPCIllustrated Parts CatalogAn OEM resource used to identify aircraft or engine parts from manufacturers, including illustrations, part numbers, and other relevant information
For Instrument Proficiency Check (IPC), see Maintenance section
KYCKnow Your CustomerA term that refers to confirming the potential buyer’s identity
LHLeft HandA component that is specifically installed on the left-hand side of the aircraft
MFGManufacturer/ManufacturingA company that produces aircraft and/or aircraft parts
NHANext Higher AssemblyA main assembly that includes several subcomponents (e.g., if a buyer is having difficulty locating a subcomponent, the buyer can review the next higher assembly including that subcomponent)
OEMOriginal Equipment ManufacturerThe original company produces aircraft or aircraft parts for specific aircraft
O&AOver and AboveAdditional costs beyond the anticipated amount
PMAParts Manufacturing ApprovalA company with regulatory authority approval to manufacture aircraft parts equivalent to the OEM aircraft parts
POPurchase OrderA document identifying the product or service, quantity, and payment amount
PNPart NumberThe aircraft or engine part’s alphanumeric identifier
RAIReturn As IsWhen an aircraft part has been inspected by a repair vendor and is returned without having repairs made to it
RFQRequest For QuoteA document issued by a potential customer requesting price and availability regarding a product or service
RHRight HandA component on the right-hand side of the part (that may have a different part number than the same type of component on the left-hand side of the aircraft part)
RMAReturned Materials AuthorizationA document authorizing the return of a product. RMAs are required to be included when the aircraft part is returned
SNSerial NumberA unique identifier for tracking purposes

Regulation Authorities

AcronymFull TitleDefinition
ANACAgência Nacional de Aviação (Brazil)Translation: National Civil Aviation Agency A national civil aviation authority (CAA) regulating and inspecting civil aviation in Brazil
CAACivil Aviation AuthorityA generic term used for a national aviation regulatory body (e.g., the FAA is the CAA in the United States)
CAAC Civil Aviation Administration of China The administration that oversees civil aviation in China
CARSCanadian Aviation RegulationsNational aviation regulatory body in Canada
CASACivil Aviation Service Authority in AustraliaA government body regulating aviation safety in Australia
CATACertification Authorities for Transport AirplanesAuthorities include aircraft certification management representatives from ANAC, EASA, FAA, and TCCA
EASAEuropean Aviation Safety AgencyThe international aviation regulatory body in Europe
FAAFederal Aviation AdministrationThe United State’s civil aviation authority (CAA)
FSDOFlight Standards District OfficeA local field office for the FAA, dealing in aviation, most commonly aircraft accident reporting
TCTransport CanadaAlso known as the Department of Transportation in Canada that regulates all forms of transportation in the country, including aviation
For Type Certificate (TC), see Certificates section
For Total Cycles (TC), see Cycles and Times section
TCCATransport Canada Civil AviationCanada’s civil aviation authority (CAA)

Wings and Leading Edges

AcronymFull TitleDefinition
LELeading EdgeThe forward portion of an aircraft flight control surface or airfoil section. It is the first part of the flight control surface to make contact with the air
IBInboardTypically, a position referenced nearest to the aircraft center line
OBOutboardTypically, a position referenced farthest from the aircraft center line
TR or T/RThurst ReverserA component used to decelerate the aircraft during landing
For Time Remaining (TR), see Cycles and Times section
WSWing StationTypically, wing stations are locations relative to the center line of the aircraft