Which types of indications are only valid above 60 KIAS in the ERJ 170/175?

In the ERJ 170/175, the true airspeed (TAS), total air temperature (TAT), and static air temperature (SAT) indications are only reliable when the aircraft is flying above 60 knots indicated airspeed (KIAS). This operational limit is crucial for ensuring the accuracy of these readings, as they rely on airflow and environmental conditions that become stable and reliable only at higher speeds. At lower speeds, the instruments may not provide accurate or consistent data due to the potential for air stagnation and other aerodynamic effects.

The other choices reflect indications that either do not have this specific limitation or are reliable at lower airspeeds. For instance, bearing and heading indications work based on the aircraft's navigational systems and are not as affected by airspeed. Similarly, altitude and speed measurements can still be performed effectively regardless of whether the aircraft is below 60 KIAS. Fuel flow readings are based on engine performance and fuel management systems, which similarly do not have this airspeed-related validity condition. Hence, understanding the requirement for TAS, TAT, and SAT to be above 60 KIAS is critical for maintaining accurate and safe operations in the ERJ 170/175.