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Hello avgeeks,

First time posting here looking for an answer. Could someone tell me what's located inside that pod on the right wing of some planes like this Pilatus PC12 or this Caravan 208? I guess it can be a gyrocompass but i am not 100% sure.

Thank you in advance!! Safe landings.

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    $\begingroup$ Related, maybe a dupe? $\endgroup$ – Pondlife Jul 23 '18 at 16:18
  • $\begingroup$ "Hello avgeeks,"? $\endgroup$ – Super Jul 23 '18 at 23:38

Its not the gyrocompass. Its where the weather radar unit is mounted since the prop prevents it from being mounted in the nose like on many larger aircraft. You can find a nice instructional video on how to use it here. The magnetometer used on many aircraft to provide magnetic heading information to the systems is much smaller than those domes.

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If you are referencing the heading indicator when talking about a gyrocompass those are panel mounted. If you are referencing the wet compass (which is balanced in fluid) those are mounted on the column in the center of the windshield typically. A lost of the more modern aircraft in this class have glass panels which use AHARS units and may not have traditional gimbals anymore.

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  • $\begingroup$ The gyrocompass can fit inside the old "round gage" housing on the control panel. With a glass panel, it's most likely mounted behind the panel somehwere. $\endgroup$ – Zeiss Ikon Jul 23 '18 at 15:53
  • $\begingroup$ The "flux valve", the magnetic sensing part of the gyrocompass, is usually out near the wing tip but they are able to fit into the wing structure so you can't see them. $\endgroup$ – John K Jul 23 '18 at 16:09
  • $\begingroup$ A whiskey compass (not wet compass) is called that because it is filled with alcohol, or some kind of oil. Glass panel heading indicators, which are replacing the heading indicators, use a magnetometer located in the rear fuselage or out in a wing, to provide the magnetic heading info that is displayed. $\endgroup$ – CrossRoads Jul 23 '18 at 16:11
  • $\begingroup$ @CrossRoads I have corrected the water mistake. $\endgroup$ – Dave Jul 23 '18 at 16:16
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    $\begingroup$ A lot of planes have also gotten away from the "wet compass" and instead use a Vertical Card Compass, which presents a layout and heading reading that matches the reading on the heading indicator (be it gyro based, or a glass panel). The Vertical Card Compass may still be installed above the glareshield/on the window, or may be mounted in the panel, more as a backup when a magnetometer is used. $\endgroup$ – CrossRoads Jul 23 '18 at 18:32

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