Aviation Terms & Abbreviations

Aircraft-ground digital messaging system; maintenance teams may encounter fault/status messages and maintenance reports.

System used to collect and process aircraft/engine condition data for monitoring and maintenance support.

Mandatory airworthiness action issued by an aviation authority when an unsafe condition requires corrective action.

Approved aircraft operating limitations and performance document; maintenance personnel may reference it for configuration/limitations context.

Mandatory airworthiness-limitation maintenance item that requires controlled compliance.

Manufacturer maintenance instructions for aircraft-level inspection, servicing, removal/installation, adjustment and testing.

Authority-approved alternative means of complying with an Airworthiness Directive requirement.

Approved/accepted maintenance programme defining scheduled maintenance tasks and intervals for an operator.

Operational status indicating an aircraft cannot return to service until required action is completed.

Onboard unit providing auxiliary electrical/pneumatic power, commonly used on the ground and for engine start support.

Integrated test/diagnostic capability used to detect or isolate faults.

Electronic control unit associated with braking and nose-wheel steering functions on applicable aircraft.

Protective electrical device used to interrupt a circuit under specified conditions.

Approved conditions/limitations for operation with certain external configuration items missing or damaged.

Maintenance, test, repair and overhaul instructions for a specific component.

Structured program for corrosion prevention, inspection and control.

Maintenance release/certification confirming required work has been completed in accordance with applicable requirements.

Number of operating cycles accumulated since the item was new.

Number of operating cycles accumulated since the last overhaul.

A defect whose rectification has been deferred under an approved process/dispatch basis.

Structured identifier used in S1000D technical publications to identify a data module.

European Union aviation safety agency responsible for common aviation safety rules and certification functions.

Airbus flight-deck monitoring and alerting system; maintenance may use associated messages for fault context.

Boeing-style engine indication and crew-alerting system; maintenance may use messages for fault context.

Date or event when an aircraft/type enters operational service.

Organization-issued engineering instruction used to control a defined technical action or modification.

Static-electricity discharge that can damage sensitive electronic components.

Operational approval framework for applicable twin-engine operations; maintenance programs include specific reliability and configuration controls.

Aircraft wiring, connectors and associated electrical interconnection elements managed as a system.

Digital engine-control system with full authority over applicable engine functions.

Takeoff/landing operating cycles used in life and maintenance tracking.

Context-dependent abbreviation; always confirm the aircraft/system documentation.

Aircraft or component operating time expressed as flight hours.

Fault-isolation procedures that help identify causes of system faults, commonly used on certain aircraft programs.

Damage risk from objects/debris that can affect aircraft, engines, components or maintenance areas.

Ground equipment used to support aircraft servicing, maintenance and handling.

Engine fuel/control unit combining hydraulic/mechanical functions on applicable engines.

Approved/accepted instructions necessary to maintain continuing airworthiness of a product or article.

Passenger entertainment system; cabin maintenance commonly deals with IFE components and connectivity.

Engine shutdown occurring in flight; an important reliability/maintenance metric in applicable programs.

Illustrated parts reference used to identify assemblies, part numbers, effectivity and installation relationships.

Part with a mandatory approved life limit tracked by hours, cycles or other approved parameter.

Component designed to be replaced at line/aircraft level within an approved maintenance concept.

Operational maintenance-control function coordinating technical issues, defects and maintenance support.

Flight-deck interface used to access multiple aircraft systems; maintenance functions may be available depending on type.

Operator-approved document defining conditions under which an aircraft may be dispatched with specified items inoperative.

Master document forming the basis for an operator-specific MEL.

Planning source containing scheduled maintenance requirements and intervals for an aircraft program.

Industry/regulatory process supporting development of scheduled maintenance requirements for transport aircraft.

Report containing initial scheduled maintenance requirements developed through the MRB process.

Industry term for organizations and activities providing aircraft, engine and component maintenance services.

Industry methodology used to develop scheduled maintenance tasks for transport aircraft.

Inspection methods used to detect defects without damaging the inspected part.

Outcome where a reported fault cannot be reproduced or confirmed during testing/inspection.

Original manufacturer of an aircraft, engine, system or component.

Structured practical training/experience performed in the work environment under applicable requirements.

FAA approval for manufacture of replacement/modification articles under applicable U.S. rules.

Manufacturer/approved identifier for a specific part or configuration.

Maintenance item requiring independent/specified inspection under applicable procedures.

Takeoff discontinued before becoming airborne; maintenance inspection requirements may apply depending on event and aircraft data.

Process/status of returning aircraft or component to service following required maintenance and release.

Manufacturer technical publication recommending or defining inspections, modifications or other technical actions.

Report used in certain regulatory systems to communicate service difficulties, failures or defects.

Unique identifier assigned to an individual aircraft, engine, component or part.

Structural damage limits, allowable damage criteria and approved repair information for applicable aircraft structure.

Defined maintenance action referenced in approved maintenance data.

Elapsed time required to complete a maintenance/repair/service process.

Specified or recommended operating interval between overhauls for applicable equipment.

Systematic troubleshooting procedures used to isolate and rectify reported faults.

Operating time accumulated since the item was new.

Operating time accumulated since the last overhaul.

Aircraft electrical wiring diagrams and interconnection information used for electrical troubleshooting and maintenance.

Maintenance activity that has been started but is not yet complete/released.

Controlled instruction/record authorizing and tracking maintenance work.

Aircraft weight excluding usable fuel; maintenance teams may encounter it in weighing/configuration records.