Every alert and notification goes through the distinct lifecycle, that starts when the event, triggering the alert, occurs. Not all steps of the lifecycle are implemented in every system, but it is necessary to keep them in mind.
Below the lifecycle of typical alert is presented.
- Active unacknowledged alert
The alert is triggered by some event. For instance, the aircraft changes its altitude more than the threshold is set. The active state of the alert indicates, that currently there is a potentially dangerous situation. The unacknowledged state means that no user or operator of the system confirmed, that he is aware of it.
- Active acknowledged alert
If the user acknowledges the alert, the system stops attracting his attention to it. But the indication is still definitely visible in order to avoid the situation that the operator has forgotten about it, especially if there are multiple concurrent alerts triggered at the same time.
- Inactive unacknowledged alert
If the user hasn’t noticed the alert or has immediately responded to it without acknowledgment, or by some other case the reason for the alert is resolved, the alert state is changed to inactive unacknowledged. Depending on the application, the alert can fully disappear or will be still visible to the operator — for instance, for post-situational analysis or to attract attention that there were some uncontrolled risky situations.
- Inactive acknowledged alert
If the user acknowledged the alert and then responded to the situation, or the situation resolved by its own, the alert becomes inactive, because there is no such situation. The acknowledged state typically means that the reaction to alert was adequate and sensible (of course, there are exceptions, especially if the reason disappeared without the user’s response). In most cases, alerts in this state are hidden immediately by default to avoid distraction and overload of the operator.