time interval

up time

down time

enabled time

externally disabled time

enabled time

down time

operating time

non-operating time

operating time

non-operating time

idle time

standby time

externally disabled time

preventive maintenance time

time to restoration

corrective maintenance time

fault detection time

administrative delay

maintenance time (see Figure 2)

RT

NRT

RT

NRT

RT

NRT

RT

NRT

RT

NOTE All times mentioned in the figure are time intervals or sequences of time intervals.

Figure 1 – Times related to operation and maintenance

Note 1 to entry: Time spent in on-line maintenance is a part of the maintenance time.

Note 2 to entry: Maintenance time excludes fault detection time and administrative delay.

maintenance time
corrective maintenance time						preventive maintenance time
logistic delay	active maintenance time								logistic delay
	active corrective maintenance time					active preventive maintenance time
	technical delay	fault localization time	fault diagnosis time	fault correction time	function checkout time	technical delay	preventive maintenance action time	function checkout time
		repair time

NOTE All times mentioned in the figure are time intervals or sequences of time intervals.

Figure 2 – Maintenance time intervals