What constitutes a condition that makes takeoff with reverser icons or EICAS warnings prohibited?

The presence of displayed warning or caution messages on the EICAS (Engine Indication and Crew Alerting System) indicates that there may be an issue requiring attention before proceeding with takeoff. These messages can alert the crew to potential malfunctions or conditions that could compromise the safety and performance of the aircraft, particularly in relation to the thrust reversers. Since thrust reversers are critical for decelerating the aircraft after landing and sometimes for takeoff in certain conditions, having any warning or caution regarding their operation or status raises a significant safety concern.

Pilots are trained to adhere to specified limitations and procedures, which make it clear that ambiguity or warnings that could indicate a malfunction justify prohibiting takeoff until the issue is adequately addressed and resolved. Therefore, the prohibition on taking off with such indications ensures the safety of both the aircraft and its occupants by preventing potentially hazardous situations from arising during critical phases of flight.