Final answer:
The EICAS indicates an invalid 10th-stage pressure transducer signal through error messages or warnings on the display.
Step-by-step explanation:
The EICAS (Engine Indicating and Crew Alerting System) is used in aircraft to indicate the status and condition of various engine and aircraft systems. It consists of multiple displays that provide information to the flight crew. In the case of a 10th-stage pressure transducer signal being invalid, the EICAS would likely display an error message or warning indicating the issue. This could be in the form of an error code, a flashing light, or a specific message on the EICAS display.