On-Condition Maintenance
Definition
A maintenance philosophy that retains components in service until inspection or sensor data indicates they have reached a defined deterioration limit, replacing fixed-interval retirement with evidence-based retirement.
- Core principle
- Retire parts based on inspection or sensor data, not fixed interval
- Alternative to
- Hard-time (fixed-interval) replacement
- Domain
- Aviation and mechanical systems maintenance
Common questions
How does on-condition maintenance relate to an accident investigation?+
Investigators check whether the component's inspection history and monitored parameters actually justified keeping it in service, since a program that lacked reliable condition data can leave a failure mode undetected until it causes an incident.
What distinguishes it from condition-based monitoring generally?+
On-condition maintenance is the maintenance philosophy or policy choice, while condition-based monitoring is the sensor and inspection infrastructure that supplies the data the policy relies on to decide when to act.
Related terms
- Blade Liberation
- The detachment of a turbine or compressor blade from its rotor disk, creating a high-energy projectile inside the engine. Certification standards require...
- Fracture Surface Analysis
- Examination of the broken face of a component to identify the failure mode. Beach marks and striations indicate fatigue, cleavage facets indicate...
- ICAO Annex 13
- The international standard that defines the objectives, conduct, and reporting of aircraft accident and serious-incident investigations. It establishes the state-of-occurrence as the...
- NTSB / AAIB
- National Transportation Safety Board (USA) and Air Accidents Investigation Branch (UK): the two national authorities whose technical methods and report standards most...
- Pressurisation Cycle Fatigue
- Fatigue damage driven by the repeated inflation and deflation of the aircraft fuselage as it climbs to altitude and descends. Each flight...