Setting the Altimeter The Altimeter on an aircraft works using air pressure. This varies due to weather conditions, so the altimeter must be set regularly to a known value. Having the correct altimeter setting is important. As well as helping pilots to avoid any high terrain, it means that aircraft can be separated by altitude and not hit each other. This is particular important in busy airspace. The source of this altimeter setting varies. At high altitudes, a standard pressure is used. At lower levels, and area setting is used, and around airports, the current airport setting is used. This tutorial will teach you how to set the altimeter based on the ATIS (Automatic Terminal Information Service) for Livermore Municipal airport. Aircraft/c172p/tutorial/radio morning KLVK 1 12 -9999 37.6952 -121.8167 175.0 0 0 0 0 /controls/gear/brake-parking 1 /controls/flight/flaps 0.0 /controls/engines/engine/magnetos 0 /controls/engines/engine/throttle 0.0 /engines/engine/running false /instrumentation/adf/frequencies/selected-khz 340 /environment/weather-scenario Fair weather /controls/flight/elevator-trim 0.17 /instrumentation/comm[0]/frequencies/selected-mhz 119.650 In this lesson, you'll learn how to set the altimeter to the Livermore ATIS. I've already set the radio to the correct frequency - 119.65 MHz 10 Listen to the ATIS message. If you cannot hear it, check the Sound Configuration item in the File menu. 10 The ATIS message said the altimeter setting was 29.97. We can set this using Equipment->Instrument Settings, or we can adjust the altimeter so that the altimeter matches the altitude of Livermore - 380ft. 10 353.8 -20.3 0.0 -0.2 0.3 0.4 15.1 To adjust the altimeter directly, use the knob on the bottom left. Click on the right to increase the altitude, and left to decrease. Use the left mouse button to make small adjustments, and the right button to make large adjustments. 353.8 -20.3 0.0 -0.2 0.3 0.4 15.1 -0.3525 -0.1640 0.0409 0.8756 Set the altimeter to 380 feet, or the pressure setting to 29.97 inHG. 353.8 -20.3 0.0 -0.2 0.3 0.4 15.1 -0.3525 -0.1640 0.0409 0.8756 That's too low. Increase the altimeter setting or altitude. /instrumentation/altimeter/setting-inhg 29.96 That's too high. Decrease the altimeter setting or altitude. /instrumentation/altimeter/setting-inhg 29.98 /instrumentation/altimeter/setting-inhg 29.96 /instrumentation/altimeter/setting-inhg 29.98 If you set the pressure setting directly, you can double-check you've set the correct value by checking the current altitude.