Quick Answer
To use an altimeter effectively, beginners should understand its limitations, set the correct reference altitude, and calibrate it before use. They should also learn to read the altimeter's display and understand the difference between an altimeter's altitude reading and an aircraft's actual altitude. Practice with a calibrated altimeter will improve their accuracy.
Calibrating the Altimeter
Calibrating an altimeter is a crucial step before using it for navigation. This involves setting the altimeter to a known reference altitude, such as mean sea level (MSL). To do this, turn the altimeter on and set the ‘BARO’ or ‘BAROMETER’ setting to ‘ALT’ or ‘ALTITUDE’. Then, find a location with a known altitude, such as a landmark or a reference point, and set the altimeter to that altitude. This process is usually done when the altimeter is first turned on, but it can also be adjusted later if necessary.
Understanding Altimeter Readings
An altimeter’s reading is not always the actual altitude of an aircraft. Factors such as atmospheric pressure, temperature, and humidity can affect the reading. For example, an altimeter set to MSL may read 200 feet higher or lower than the actual altitude due to changes in atmospheric pressure. To improve accuracy, pilots should understand how to use the altimeter’s ‘QNH’ or ‘SEA LEVEL PRESSURE’ setting to adjust for these factors.
Interpreting Altimeter Displays
An altimeter’s display typically consists of an analog needle or a digital readout showing the altitude in feet or meters above the reference altitude. Beginners should learn to quickly read this display and understand the relationship between the altimeter’s reading and the aircraft’s actual altitude. They should also learn to identify any warnings or anomalies on the display, such as a ‘LOW’ or ‘HIGH’ indication, which may indicate a problem with the altimeter.
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