Final answer:
The de clutter of EICAS activates when there is an abnormal condition or fault detected by the system. It removes irrelevant information and prioritizes important alerts for the pilot.
Step-by-step explanation:
On an aircraft, the de clutter of EICAS (Engine Indicating and Crew Alerting System) activates when there is an abnormal condition or fault detected by the system.
For example, if the EICAS detects an issue with the engine, such as low oil pressure or high temperature, it will activate the de clutter function to remove irrelevant information from the display and prioritize the important alerts for the pilot.
The de clutter feature helps the pilot to focus on critical information and take necessary actions in a timely manner.