In colder-than-standard conditions, which statement correctly describes the relationship between indicated altitude and true altitude?

• A. Indicated altitude is lower than true altitude.
• B. Indicated altitude is higher than true altitude.
• C. They are the same.
• D. Cannot be determined.

Answer: (B)

In colder-than-standard conditions, the pressure–height relationship used by the altimeter shifts away from the standard model. The altimeter is calibrated to convert ambient pressure to altitude assuming the standard atmosphere. When the air is colder, the pressure at a given true height is lower than what the standard atmosphere would predict. The altimeter interprets that lower pressure as being at a higher altitude in the standard model, so it shows a higher altitude than the aircraft’s actual height. That’s why indicated altitude ends up higher than true altitude in cold conditions.

This doesn’t happen in the same way if the air were warmer, and the other options wouldn’t fit because temperature changes alter the pressure-to-altitude mapping that the instrument relies on.