What typical symptom might indicate that your altimeter is not set correctly during flight?

When an altimeter is not set correctly, it can lead to an incorrect reading of the aircraft's altitude. If the altimeter is set to a pressure that is too low, it may cause the aircraft to gain altitude unexpectedly. This happens because the altimeter interprets the air pressure at a given altitude as being at a higher elevation, which can result in the pilot believing that they are flying lower than actual altitude and inadvertently climbing.

In this context, an unexpected altitude gain can be a critical indication that the altimeter needs to be corrected. Monitoring altitude is crucial for safe flight operations, especially when maintaining separation from terrain and other aircraft. Therefore, an aircraft ascending unexpectedly is a significant indicator that the altimeter setting should be checked and verified for accuracy.

Other symptoms like fluctuations in instrument panel lighting, descent indications, or navigation issues could stem from different problems not directly related to the altimeter setting or provide inaccurate altitude information. Thus, recognizing the correct symptom associated with altimeter discrepancies is vital for maintaining flight safety.