Australia CASA Instrument Proficiency Practice Exam

The standard atmospheric conditions at sea level are defined as 15°C for temperature and 29.92 inHg (which is equivalent to 1013.25 hPa) for atmospheric pressure. These values are established by the International Civil Aviation Organization (ICAO) as a basis for various calculations in aviation, meteorology, and other fields that require a standard reference for atmospheric conditions.

The temperature of 15°C represents the average temperature at sea level which is a key parameter for understanding air density, which affects lift and performance calculations in aviation. The pressure of 29.92 inHg signifies standard atmospheric pressure, which is fundamental for calibrating altimeters and ensuring accurate altitude readings. This standard is critical for flight safety and operational procedures, as it allows pilots and aircraft systems to gauge altitude accurately in relation to expected atmospheric conditions.

The other options present varying temperature and pressure values that do not align with established standard atmospheric conditions, making them less applicable for standard reference in aviation practices.