How is the TAS altitude block selected?

The selection of the True Airspeed (TAS) altitude block is accomplished by using the normal/below/above pushbutton selector switch. This control allows the pilot to choose the altitude block based on the aircraft's current flight profile. By pressing the appropriate pushbutton, the pilot can indicate whether the aircraft is operating at normal altitude, below a certain threshold, or above it, which is essential for various flight functions, including altitude warning systems and autopilot operations.

Understanding this selection process is crucial for effective flight management and ensuring the aircraft operates safely within its designated altitude parameters while using the electronic systems correctly.