ASA Aircraft Instrument Systems Practice Test

The accuracy of an altimeter is primarily influenced by changes in atmospheric pressure and calibration errors. Altimeters are designed to measure changes in air pressure; as an aircraft ascends or descends, the surrounding atmospheric pressure changes. If the atmospheric pressure varies due to weather conditions or altitude, the altimeter may not provide an accurate reading unless it is properly calibrated to the current air pressure at sea level.

Calibration errors can also contribute to inaccuracies. Altimeters must be regularly checked and adjusted to ensure they reflect the correct pressure setting. If the altimeter is incorrectly calibrated, it will not give an accurate indication of the aircraft's altitude, regardless of the actual air pressure. This is particularly significant during flight operations, as navigational decisions and safety are directly dependent on accurate altitude readings.

Factors like aircraft weight and balance, flight altitude, geographical location, time of day, and visibility conditions don't directly affect the altimeter's ability to measure altitude based on pressure. While certain operational considerations, such as proper weight distribution, are essential for overall aircraft performance, they do not inherently alter the fundamental function of the altimeter system.

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