If the temperature outside an aircraft drops from +5 °C to 0 °C while at 10,000 feet, what will happen to the aircraft's indicated altitude?

If the temperature outside an aircraft drops from +5 °C to 0 °C while at 10,000 feet, what will happen to the aircraft's indicated altitude?

• A. It will be lower than indicated
• B. It will be accurately indicated
• C. It will be higher than indicated
• D. It will fluctuate randomly

Answer: (C)

When the temperature drops as indicated in the scenario, the density of the air also decreases. This is due to the principles of atmospheric science where cooler air is denser than warmer air at the same pressure. In an aircraft, altimeters are calibrated based on standard atmospheric conditions, which assume a specific temperature and pressure relationship. When the air temperature decreases, the air becomes denser, causing the aircraft to effectively "sink" in relation to the indicated altitude it would have read if the temperature were at a standard level. The altimeter, which depends on the pressure of the air around the aircraft, will not account for this decrease in temperature. Therefore, the aircraft may inadvertently be at a lower actual altitude than what the altimeter indicates. In this case, because the temperature dropped from +5 °C to 0 °C, the aircraft will be at a higher altitude than what is indicated by the altimeter because it is denser air that causes lower actual altitude readings. Thus, the aircraft's indicated altitude will reflect that it is higher than it actually is, confirming that the indicated altitude will be higher than it truly is due to the change in temperature.

When the temperature drops as indicated in the scenario, the density of the air also decreases. This is due to the principles of atmospheric science where cooler air is denser than warmer air at the same pressure. In an aircraft, altimeters are calibrated based on standard atmospheric conditions, which assume a specific temperature and pressure relationship.

When the air temperature decreases, the air becomes denser, causing the aircraft to effectively "sink" in relation to the indicated altitude it would have read if the temperature were at a standard level. The altimeter, which depends on the pressure of the air around the aircraft, will not account for this decrease in temperature. Therefore, the aircraft may inadvertently be at a lower actual altitude than what the altimeter indicates.

In this case, because the temperature dropped from +5 °C to 0 °C, the aircraft will be at a higher altitude than what is indicated by the altimeter because it is denser air that causes lower actual altitude readings. Thus, the aircraft's indicated altitude will reflect that it is higher than it actually is, confirming that the indicated altitude will be higher than it truly is due to the change in temperature.