Final Answer:
In an ECAM control panel, T.O. (Takeoff) and LDG (Landing) INHIBIT messages are displayed when the aircraft is on the ground with the parking brake engaged.
Step-by-step explanation:
The ECAM (Electronic Centralized Aircraft Monitor) control panel in modern aircraft provides critical system information to the flight crew. The T.O. and LDG INHIBIT messages appear when the aircraft is on the ground with the parking brake engaged.
These messages indicate that certain system functionalities, such as the automatic deployment of spoilers during takeoff and landing, are inhibited due to the parking brake being set. It serves as a reminder to the flight crew about the status of these systems, ensuring that they are aware of the inhibitions in place while the aircraft is on the ground.