Status	Definition	Usages/Synonyms
INITIATING	the service is starting-up and is not accessible?
AVAILABLE_RUNNING	the service is operational and accessible immediately when invoked	Available
PARTIAL_FAILURE	the service is operational and accessible but it is reduced in quality	Degraded
SERVICE_NOT_AVAILABLE	the service is not operational or accessible	Unavailable
		Unknown

Resources

https://learn.microsoft.com/en-us/rest/api/resourcehealth/availability-statuses/list?view=rest-resourcehealth-2024-02-01&tabs=HTTP
https://www.secoda.co/glossary/what-is-service-availability
ICAO Doc 10203 statements:
- Operational monitoring by the information service provider is in place and the information service continues to meet all QoS requirements.
- Availability of a service. The degree to which an information service is operational and accessible when required for use. Availability represents the probability that an information service is ready and available immediately when invoked.

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