definition of the maintenance echelons, indenture levels, maintenance levels, maintenance support, and
Note 1 to entry: The maintenance concept provides the basis for maintenance planning, determining supportability
requirements and developing logistic support.
Note 2 to entry: A maintenance echelon is a position in an organization where specified levels of maintenance are
to be carried out (e.g. field, repair shop, manufacturer facility).
[SOURCE: IEC 60050‑191]
Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global Standards