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Other
“-ilities”
I Level
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INFOSEC
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Inherent Availability (AI)
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Initial Capabilities Document (ICD)
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Interface Control Agreement (ICA)
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Investments/Investment Cost
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ISA
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ISO
ISP
ISR
ISSA
Issue
Issue Cycle
Issue Papers
IT
ITA
ITAB
Item Detail Specification
Item Performance Specification
Item-Unique Identification (IUID)
Items of Intrinsic Military Utility
Iteration
ITMRA
ITOPS
ITP
ITR
ITS
ITWA
IUID
IV&V
IW



   

Inherent Availability (AI)

Availability of a system with respect only to operating time and corrective maintenance. AI ignores standby and delay times associated with preventive maintenance as well as Mean Logistics Delay Time (MLDT) and may be calculated as the ratio of Mean Time Between Failure (MTBF) divided by the sum of MTBF and Mean Time To Repair (MTTR), that is:

AI = MTBF รท (MTBF + MTTR)