20 State of alerts
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Resolutions - Maritime Safety Committee - Resolution MSC.252(83) - Adoption of the Revised Performance Standards for Integrated Navigation Systems (INS) - (Adopted on 8 October 2007) - Annex - Performance Standards for Integrated Navigation Systems (INS) - Module C - Alert management - 20 State of alerts

20 State of alerts

Parent topic: Module C - Alert management

20.1 General

  20.1.1 The presentation of alarms and warnings is defined in the performance standards for presentation of navigation-related information on shipborne navigational displays (resolution MSC.191(79)).

  20.1.2 The state of an alert should be unambiguous for the alert management, the INS and all associated operational and sensor/source displays.

20.2 Alarms

  20.2.1 The alert management should distinguish between different announcement states of each individual alarm:

  • unacknowledged alarm
  • acknowledged alarm.

  20.2.2 When an alarm condition is detected, it should be indicated as unacknowledged alarm:

  • (a) initiate an audible signal, accompanied by the visual alarm announcement;

  • (b) provide a message of sufficient detail to enable the bridge team to identify and address the alarm condition;

  • (c) may be accompanied by speech output presented at least in English.

  20.2.3 An unacknowledged alarm should be clearly distinguishable from those existing and already acknowledged. Unacknowledged alarms should be indicated flashing and by an audible signal.

  20.2.4 The characteristics of the audible alarm signal, whether used singly or in combination with speech, should be such that there is no possibility of mistaking it for the audible signal used for a warning.

  20.2.5 It should be possible to temporarily silence alarms. If an alarm is not acknowledged within 30 s the audible signal should start again or as specified in the equipment performance standards.

  20.2.6 The audible signal, if not temporarily silenced, and the visual signal for an unacknowledged alarm should continue until the alarm is acknowledged, except specified otherwise in the equipment performance standards.

  20.2.7 An acknowledged alarm should be indicated by a steady visual indication.

  20.2.8 The visual signal for an acknowledged alarm should continue until the alarm condition is rectified.

20.3 Warnings

  20.3.1 The alert management should distinguish between different announcement states of each individual warning:

  • unacknowledged warning
  • acknowledged warning.

  20.3.2 When a warning condition is detected, it should be indicated as unacknowledged warning:

  • (a) initiate an momentarily audible signal, accompanied by the visual warning announcement;

  • (b) provide a message of sufficient detail to enable the bridge team to identify and address the warning condition;

  • (c) may be accompanied by speech output presented at least in English.

  20.3.3 An unacknowledged warning should be clearly distinguishable from those existing and already acknowledged. Unacknowledged warnings should be indicated by a flashing and by an audible signal.

  20.3.4 When a warning occurs a momentarily audible signal should be given. The characteristics of the audible warning signal, whether used singly or in combination with speech, should be such that there is no possibility of mistaking it for the audible signal used for an alarm.

  20.3.5 The visualization for an unacknowledged warning should continue until the warning is acknowledged, except specified otherwise in the equipment performance standards.

  20.3.6 An acknowledged warning should be indicated by a steady visual indication.

  20.3.7 The visual signal for an acknowledged warning should continue until the warning condition is rectified.

20.4 Cautions

  20.4.1 A caution should be indicated by a steady visual indication. No acknowledgement should be necessary for a caution.

  20.4.2 A caution should be automatically removed after the condition is rectified.

  20.4.3 A message should be provided of sufficient detail to enable the bridge team to identify and address the caution condition.

20.5 Alert escalation

  20.5.1 After a time defined by the user unless otherwise specified by the organization, an unacknowledged alarm should be transferred to the bridge navigational watch alarm system (BNWAS), if available. The unacknowledged alarm should remain visible and audible.

  20.5.2 An unacknowledged warning should be changed to alarm priority, as required by specific requirements for the individual equipment or after 60 s unless otherwise set by the user.

  20.5.3 The alert escalation should be in compliant with the alert escalation requirements of the individual performance standards.

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