Understand the term. See where it applies. Keep learning.
Start with a clear definition, then connect the term to aircraft, ATA chapters, technical resources, videos, discussions and real maintenance lessons.
Glossary explanations support understanding. Approved manuals, engineering instructions and company procedures remain the authority for maintenance action.
103 definitions found
AD
AD, Airworthiness DirectiveAirworthiness Directive: a legally enforceable requirement addressing an unsafe condition.
Understand and continue →Airworthiness
continued airworthiness conditionThe condition of an aircraft or product meeting its approved design and being safe for operation.
Understand and continue →AMM
Aircraft Maintenance Manual, AMMAircraft Maintenance Manual: the controlled aircraft-specific source for maintenance procedures and system descriptions.
Understand and continue →ATA
Air Transport Association chapter system, ATA, ATA chapter systemA common chapter-numbering system used to organize aircraft systems and technical information.
Understand and continue →Effectivity
aircraft effectivity, applicabilityThe exact aircraft, model, serial range, configuration or component to which technical information applies.
Understand and continue →Human factors
maintenance human factorsThe study of how people, tools, tasks, organizations and environments affect performance and safety.
Understand and continue →MEL
MEL, Minimum Equipment ListMinimum Equipment List: operator-specific conditions under which an aircraft may be dispatched with certain items inoperative.
Understand and continue →Troubleshooting
fault finding, fault isolationA disciplined process for confirming, isolating and correcting the cause of a fault.
Understand and continue →FOD
FOD, Foreign Object Damage, foreign object debrisForeign Object Damage: damage caused by an object, substance or debris not intended to be present.
Understand and continue →Line maintenance
line station maintenanceMaintenance performed in an operational environment to support continued aircraft service.
Understand and continue →Shift handover
maintenance handover, task turnoverA structured transfer of maintenance status, risks, unfinished work and aircraft configuration between personnel or shifts.
Understand and continue →Continuing airworthiness
continued airworthiness managementThe processes that keep an aircraft compliant with airworthiness requirements throughout its operating life.
Understand and continue →EASA Part-66
aircraft maintenance licence, EASA Part 66, Part-66The EASA regulatory framework for aircraft maintenance licences and certifying-staff categories.
Understand and continue →EWIS
Electrical Wiring Interconnection System, EWISElectrical Wiring Interconnection System: the aircraft wiring, connectors, splices, supports and related installation used to distribute electrical power and signals.
Understand and continue →Fly-by-wire
FBW, Fly By WireA flight-control architecture in which pilot commands are transmitted and processed electrically rather than solely through direct mechanical linkage.
Understand and continue →NDT
NDT, Non-Destructive Inspection, Non-Destructive TestingNon-Destructive Testing: inspection methods used to detect material or structural discontinuities without damaging the item.
Understand and continue →APU
APU, Auxiliary Power UnitAuxiliary Power Unit: a small gas turbine that can provide aircraft power and starting support.
Understand and continue →Base maintenance
hangar maintenance, heavy maintenanceExtensive planned maintenance normally performed in a hangar or dedicated maintenance facility.
Understand and continue →IPC
Illustrated Parts Catalog, Illustrated Parts Catalogue, IPCIllustrated Parts Catalogue: a configuration-based reference for identifying aircraft parts and assemblies.
Understand and continue →Revision status
amendment status, document revisionThe edition, revision or amendment level that identifies the current state of a controlled document or software item.
Understand and continue →Technical log
aircraft technical log, tech logThe controlled operational record used to document aircraft status, defects, maintenance actions and release information.
Understand and continue →Tool control
tooling accountabilityA system for accounting for tools and preventing missing-tool and foreign-object hazards.
Understand and continue →Task card
job card, work cardA controlled work instruction used to accomplish and record a specific maintenance task.
Understand and continue →Work package
check package, maintenance work packageA controlled collection of maintenance tasks planned for an aircraft, component or visit.
Understand and continue →Bird strike
wildlife strikeAn impact between an aircraft and a bird or other wildlife.
Understand and continue →Circuit breaker
CB, electrical circuit breakerA resettable protective device that interrupts an electrical circuit when current exceeds its designed condition.
Understand and continue →GVI
General Visual Inspection, GVIGeneral Visual Inspection: a visual examination from touching distance under normally available lighting and access conditions.
Understand and continue →LRU
Line Replaceable Unit, LRULine Replaceable Unit: equipment designed to be removed and replaced at line-maintenance level as a complete unit.
Understand and continue →Air-conditioning pack
air conditioning pack, ECS packA system assembly that regulates, cools and conditions pneumatic air for cabin or equipment use.
Understand and continue →AMO
AMO, Approved Maintenance Organisation, Approved Maintenance OrganizationApproved Maintenance Organisation: a maintenance organization holding authority approval for a defined scope of work.
Understand and continue →Angle of attack
Angle of Attack, AOAThe angle between the local airflow and a defined reference line on the aircraft or wing.
Understand and continue →Approved data
approved maintenance dataTechnical data formally approved or accepted as approved under the applicable regulatory system for the intended maintenance action.
Understand and continue →Autopilot
AP, automatic pilotAn automatic flight-control function that commands aircraft controls to follow selected guidance or stabilize flight.
Understand and continue →Cabin altitude
pressure altitude of cabinThe atmospheric altitude corresponding to the pressure maintained inside the aircraft cabin.
Understand and continue →CMM
CMM, Component Maintenance ManualComponent Maintenance Manual: controlled instructions for maintenance of a specific component or component family.
Understand and continue →Deferred defect
carried-forward defect, open deferred itemA known defect whose rectification has been postponed under an approved control process.
Understand and continue →Life-limited part
life limited part, LLPA part with an approved maximum life expressed in cycles, hours, calendar time or another defined parameter.
Understand and continue →MPD
Maintenance Planning Document, MPDMaintenance Planning Document: manufacturer planning information used to develop an operator maintenance program.
Understand and continue →Repetitive inspection
repeat inspectionAn inspection required again at defined intervals until terminating action or another approved condition is reached.
Understand and continue →BITE
BITE, Built-In Test EquipmentBuilt-In Test Equipment: system functions that monitor, test and report equipment or system condition.
Understand and continue →Bleed air
compressor bleed air, pneumatic bleed airCompressed air extracted from an engine compressor or supplied by another pneumatic source.
Understand and continue →CDL
CDL, Configuration Deviation ListConfiguration Deviation List: approved dispatch conditions for certain missing external parts.
Understand and continue →Central maintenance system
Central Maintenance Computer, central maintenance system, CMSAn aircraft system that collects, organizes and displays maintenance messages and test information from multiple systems.
Understand and continue →Detailed inspection
DET, Detailed Visual InspectionAn intensive visual examination of a specific item, installation or assembly to detect damage, failure or irregularity.
Understand and continue →FADEC
FADEC, Full Authority Digital Engine ControlFull Authority Digital Engine Control: an electronic architecture that manages engine operation within its certified authority.
Understand and continue →FIM
Fault Isolation Manual, FIMFault Isolation Manual: controlled fault-isolation procedures and decision logic for applicable aircraft systems.
Understand and continue →Hard-time maintenance
fixed-interval maintenanceA maintenance process requiring removal, overhaul or discard at a fixed approved interval.
Understand and continue →On-condition maintenance
on conditionA maintenance process in which periodic inspections or tests determine whether an item can remain in service.
Understand and continue →SB
SB, Service BulletinService Bulletin: manufacturer-issued technical information about inspections, modifications or product changes.
Understand and continue →SRM
SRM, Structural Repair ManualStructural Repair Manual: controlled data containing structural damage limits and standard repairs within stated applicability.
Understand and continue →TSM
Troubleshooting Manual, TSMTroubleshooting Manual: controlled aircraft-specific logic for isolating reported faults.
Understand and continue →WDM
WDM, Wiring Diagram ManualWiring Diagram Manual: controlled electrical interconnection and wiring information for an aircraft configuration.
Understand and continue →Zonal inspection
zonal inspection program, zonal inspection programmeA structured inspection of a defined aircraft zone for installation condition, damage, contamination and general deterioration.
Understand and continue →Air cycle machine
ACM, Air Cycle MachineAir Cycle Machine: rotating equipment that cools and conditions compressed air in an aircraft environmental-control system.
Understand and continue →Autothrottle
A/T, automatic throttle, autothrustAn automatic system that commands thrust-lever or engine-thrust changes to meet selected flight targets.
Understand and continue →Bonding and grounding
aircraft grounding, electrical bondingElectrical connections that control voltage differences, provide return paths and protect against static, fault and lightning effects.
Understand and continue →Borescope inspection
remote visual inspection, RVIA remote visual inspection using an optical or video instrument to view inaccessible internal areas.
Understand and continue →Bus tie
bus-tie contactor, electrical bus tieA controlled electrical connection that allows power transfer between normally separate electrical buses.
Understand and continue →Compressor stall
compressor blade stallA localized disruption of smooth airflow through one or more compressor stages.
Understand and continue →EASA Part-145
EASA Part 145, maintenance organisation approval, Part-145The EASA regulatory framework for approval of organizations that maintain aircraft, engines, components and appliances within defined scope.
Understand and continue →EEC
EEC, Electronic Engine ControlElectronic Engine Control: a computer that manages or participates in engine-control functions.
Understand and continue →Fatigue
fatigue crackingProgressive material damage caused by repeated or fluctuating loads, often at stresses below one-time failure strength.
Understand and continue →Hot start
overtemperature startAn engine start in which temperature exceeds the approved start limit or rises abnormally toward it.
Understand and continue →Hung start
hung engine startAn engine start in which rotor speed stops accelerating at an abnormally low value.
Understand and continue →Hydraulic accumulator
hydraulic pressure accumulatorA pressure-storage device that uses compressed gas to store hydraulic energy.
Understand and continue →IDG
IDG, Integrated Drive GeneratorIntegrated Drive Generator: an engine-driven unit that combines constant-speed drive and electrical generation functions.
Understand and continue →Load path
structural load pathThe route through which forces are transferred across an aircraft structure or component.
Understand and continue →MMEL
Master Minimum Equipment List, MMELMaster Minimum Equipment List: type-level relief developed for an aircraft model and used as the basis for operator MELs.
Understand and continue →NEF
NEF, Nonessential Equipment and FurnishingsNonessential Equipment and Furnishings: items not required for safe operation under the applicable approved program.
Understand and continue →Outflow valve
cabin outflow valveA controlled valve that regulates cabin pressure by managing the amount of air leaving the pressure vessel.
Understand and continue →PTU
Power Transfer Unit, PTUPower Transfer Unit: a device that transfers hydraulic power between systems without mixing their fluid.
Understand and continue →RAT
Ram Air Turbine, RATRam Air Turbine: a deployable turbine that uses airflow to provide emergency hydraulic or electrical power.
Understand and continue →Stall warning system
stall warning, stick shaker systemA system that warns when the aircraft approaches an aerodynamic stall condition.
Understand and continue →Static inverter
DC-to-AC inverterSolid-state equipment that converts direct current into alternating current.
Understand and continue →TRU
Transformer Rectifier Unit, TRUTransformer Rectifier Unit: equipment that converts alternating current to direct current for aircraft electrical systems.
Understand and continue →Wet start
no-lightoff start, wet engine startAn unsuccessful engine start in which fuel enters the combustion section without proper ignition.
Understand and continue →Type rating
aircraft type rating, type endorsementA qualification associated with a specific aircraft type or group under the applicable regulatory system.
Understand and continue →Penetrant testing
Dye Penetrant Inspection, Liquid Penetrant Inspection, PTA surface NDT method that uses a liquid penetrant to reveal discontinuities open to the surface.
Understand and continue →MRBR
Maintenance Review Board Report, MRBRMaintenance Review Board Report: approved minimum scheduled-maintenance requirements developed through the MRB process.
Understand and continue →Acceptable data
acceptable technical dataTechnical information considered acceptable to the authority for defined maintenance purposes, without necessarily being individually approved.
Understand and continue →CAMO
CAMO, Continuing Airworthiness Management Organisation, Continuing Airworthiness Management OrganizationContinuing Airworthiness Management Organisation: an organization approved under the applicable EASA framework to manage defined continuing-airworthiness functions.
Understand and continue →Certificate of Release to Service
Certificate of Release to Service, CRS, maintenance releaseA formal certification that specified maintenance has been completed and the product is released within the applicable regulatory scope.
Understand and continue →Compressor surge
engine compressor surgeA major instability in which compressor airflow and pressure rise break down across much of the compressor system.
Understand and continue →Condition monitoring
condition-monitored maintenanceA maintenance process that uses operational and reliability data to identify adverse performance trends.
Understand and continue →CPCP
Corrosion Prevention and Control Program, CPCPCorrosion Prevention and Control Program: a structured process for preventing, detecting and correcting aircraft corrosion.
Understand and continue →EGT margin
EGT margin, exhaust gas temperature marginThe difference between an engine exhaust-gas-temperature limit and the temperature required to produce a defined rated thrust.
Understand and continue →Engine trend monitoring
engine condition trend monitoring, ETMThe collection and analysis of engine performance data to identify gradual deterioration or abnormal trends.
Understand and continue →ETOPS/EDTO
EDTO, ETOPS, Extended Diversion Time Operations, Extended OperationsOperational approval for flights that can remain beyond a defined diversion time from an adequate aerodrome.
Understand and continue →Flight control computer
FCC, Flight Control ComputerA computer that processes commands and sensor inputs to control or monitor aircraft flight-control functions.
Understand and continue →MOE
Maintenance Organisation Exposition, Maintenance Organization Exposition, MOEMaintenance Organisation Exposition: the controlled manual describing how an EASA Part-145 organization complies with its approval requirements.
Understand and continue →Reliability program
maintenance reliability program, maintenance reliability programmeA controlled process for measuring maintenance-program performance and identifying adverse fleet trends.
Understand and continue →SDI
SDI, Special Detailed InspectionSpecial Detailed Inspection: an intensive examination using specialized techniques or equipment.
Understand and continue →Structural significant item
SSI, Structural Significant ItemA structural detail, element or assembly whose failure could affect aircraft structural integrity.
Understand and continue →Certifying staff
authorized certifying personnel, certification staffAuthorized personnel who certify maintenance release within a regulatory and organizational approval system.
Understand and continue →Company authorization
authorization scope, company certifying authorizationAn organization-issued permission defining what a person may certify or perform within that organization.
Understand and continue →Composite repair
bonded composite repairA controlled repair to fiber-reinforced structure using approved materials, lay-up, bonding and cure requirements.
Understand and continue →Damage tolerance
damage-tolerant designA design and maintenance approach that assumes flaws can exist and ensures they are detected before structural strength becomes unacceptable.
Understand and continue →Eddy current testing
Eddy Current Inspection, ETAn electromagnetic NDT method used mainly on conductive materials to detect surface and near-surface discontinuities.
Understand and continue →Magnetic particle testing
Magnetic Particle Inspection, MTAn NDT method for detecting surface and near-surface discontinuities in ferromagnetic materials.
Understand and continue →MSG-3
Maintenance Steering Group-3, MSG-3A structured industry analysis method used to develop scheduled maintenance requirements for aircraft systems, structures and zones.
Understand and continue →Radiographic testing
Radiographic Inspection, RT, X-ray inspectionAn NDT method using penetrating radiation to create an image of internal structure and discontinuities.
Understand and continue →TFU
Technical Follow-Up, TFUTechnical Follow-Up: manufacturer technical communication used to monitor and explain in-service issues.
Understand and continue →Ultrasonic testing
Ultrasonic Inspection, UTAn NDT method that uses high-frequency sound to detect internal discontinuities or measure material thickness.
Understand and continue →