The operational rules

Rules for normal operation

The selection of the steering modes had to follow rules defining normal navigation.

One of the rules that could detect the exceptional situation is about restricting the access to the steering Control mode (which disconnected the rudder from the wheel) in normal navigation. Accordingly, the scenario specification should have included the following rules :

• In the Navigation mode, the steering modes (Manual and Automatic) should be accessible, and the access to the Command (Disconnect) mode should be restricted
• In the Maintenance mode, all three steering modes should be accessible.

The resilient navigation rules are depicted here ...

Rules for alarm generation

In case of detection of an exceptional situation, a rule should enable providing proper alarms, referring to recovery instructions.

Rules for emergency operation

Rules specifying means for the operator (the captain) for setting special emergency modes:

• Control mode: overriding the protection envelop, to use when the operator knows for sure what to do
• Trust mode: let the machine decide about the safe activities, to use in case of confusion.

  Guidelines about specifying rules for human-machine control allocation 

Updated on 20 Apr 2016.