Suppression time limit. The system should inform the crew if an alarm is inhibited or suppressed for an extended period of time. Crew Interface, Displays And Controls 4.1 Alarm classifications. Alarms must be classified depending on the potential severity of the consequences of the annunciated problem and the immediacy for crewaction. Events triggering these alarms are of such potential severity as to threaten the health and safety of the crew and potential loss of the spacecraft.
Immediate action is required by the crew to attain a safe configuration or provide for crew safety.
Events in this category are of a nature that the crew needs to be aware of them and take appropriate corrective action when time permits. These events do not immediately imperil the crew or spacecraft but generally indicate off-nominal system performance or low level failures. Examples of events triggering a caution alarm would be events such as low voltage on a non-critical electrical bus or low pressure in a gas storage tank. An advisory requires an off-nominal correction by automated response but no crew intervention. 4.2 Controls, Displays and Signals 4.2.1 Standardization.