FAA Jeppesen Instrument Rating Practice Exam: Prep, Questions & Study Guide

When the air temperature is lower than the standard atmospheric temperature at a given altitude, the altimeter will indicate a higher altitude than the actual altitude. This is because the altimeter relies on the standard atmospheric pressure and temperature to calibrate its readings.

As the temperature decreases below the standard, the density of the air becomes greater than what the altimeter assumes based on its calibration. This leads to a situation where the altitude indicated by the altimeter appears higher than the true altitude because the altimeter is calibrated to a standard atmosphere that does not account for the cold air. Thus, when flying in colder conditions, pilots need to be aware that their altimeter may show them at a higher altitude than they actually are, which is essential for maintaining safe separation from terrain and other aircraft.

Understanding this concept is crucial for accurate altitude management during flight, especially in varying weather conditions, which can affect aircraft performance and safety.