What must pilots ensure when modifying the cockpit display configuration?

When modifying the cockpit display configuration, it is crucial for pilots to ensure that primary flight instrumentation is always present. This is because primary flight instruments display the essential information required for safe operation of the aircraft, such as altitude, airspeed, attitude, and heading. These instruments are vital for maintaining situational awareness and for executing safe flight maneuvers, particularly during critical phases of flight like takeoff and landing.

If the primary flight instruments were not visible or functional, it could lead to disorientation and poor decision-making, potentially compromising safety. Therefore, maintaining the visibility and operability of these critical instruments is a fundamental requirement during any modification to the cockpit display setup. In contrast, while it's important to consider calibration of non-primary instruments, updates to flight software, and the functionality of communication devices, these do not take precedence over ensuring that the primary flight instruments are intact and accessible.