What does a red indicator in navigation systems represent?

In navigation systems, a red indicator typically signifies an invalid data condition. This color is universally recognized as a warning that something is not functioning as expected or that the information being presented is not reliable.

When red appears, it alerts the navigator to check the system more closely, as it suggests that the data may be erroneous or compromised, which is vital for safe navigation. Operating with invalid data could lead to significant navigation errors or dangerous situations at sea. Therefore, understanding that a red indicator means invalid data helps navigators maintain awareness of the system's integrity and take appropriate action to rectify any issues before proceeding.