During conditions of high airport temperature and low pressure, what happens to Pressure Altitude?

Pressure altitude is the altitude in the standard atmosphere at which the pressure is equal to the current atmospheric pressure. It is directly influenced by temperature and pressure changes.

During high airport temperatures, the air becomes less dense, which typically results in a decrease in pressure altitude. However, when considering low pressure conditions, the pressure altitude is defined as being higher than that indicated by the altimeter (which is set based on local atmospheric pressure) because low pressure indicates a higher altitude at which the same pressure would be found in standard conditions.

As a result, under conditions of high temperatures combined with low atmospheric pressure, the pressure altitude actually increases. This increase occurs because the combination of warm air and low pressure means the air is less dense, thus causing aircraft to experience more altitude than what their altimeters would indicate based on the lower pressure reading.

This leads to the conclusion that pressure altitude increases when both high temperature and low pressure coexist. Understanding this relationship is essential for pilots in ensuring proper altitude readings and maintaining safe flight operations.