A formal notification that a purchase order or shop order must be modified in some way. This change can result from a revised quantity, date, or specification by the customer; an engineering change; a change in inventory requirement date; etc.
Unscheduled maintenance or repair actions, performed as a result of failures or deficiencies, to restore items to a specific condition. Maintenance is done to bring an asset back to its standard functional performance; any maintenance activity which is required to correct a failure that has occurred or is in the process of occurring. This activity may consist of repair, restoration or replacement of components.
Parts or materials that are not used often enough to meet detailed stock accounting criteria but are stocked insurance items because of their importance to down time and/or the lead time involved in procuring replacements.
The time that an item of equipment is out of service as a result of an equipment failure. The time that an item of equipment is available, but not utilized is generally not included in the calculation of downtime.