What does the illumination of both red and amber OIL PX annunciators indicate?

When both the red and amber OIL PX annunciators illuminate, they indicate a potential failure of the Fuel Control System (SCU - Scavenge Control Unit). The red annunciator typically signifies an urgent issue, such as low oil pressure, while the amber light serves to provide a cautionary alert to the pilot regarding the system's condition. The simultaneous illumination of both lights suggests a more significant problem, potentially indicating that the SCU is malfunctioning and unable to regulate oil pressure adequately.

In the context of aircraft systems, understanding the role of these annunciators is crucial for maintaining safety and responding accordingly. Each light serves a specific purpose: the red light demands immediate attention due to its critical nature, whereas the amber light indicates a caution that requires monitoring. The combination of both lights signals more than just low oil pressure; it strongly indicates that there is likely a broader issue with the oil system's functionality, warranting immediate investigation and corrective action.