FAA Ground School Practice Test

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Prepare for the FAA Ground School Test. Study with practice questions and explanations. Master your exam!

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What causes deviation error in a magnetic compass?

Weather conditions
Magnetic variation
Certain metals and electrical systems
Pilot error

The correct answer is: Certain metals and electrical systems

Deviation error in a magnetic compass is primarily caused by magnetic fields generated by certain metals and electrical systems in an aircraft. These nearby magnetic influences can create distortions in the magnetic field, leading to inaccurate compass readings. This is crucial for pilots to understand since it highlights the importance of being aware of any equipment or materials in the cockpit that can interfere with the compass. Understanding deviation is vital for navigation, as it affects the accuracy of the heading reported by the compass. Unlike magnetic variation, which is a geographical difference between true north and magnetic north, deviation error is specific to the individual aircraft and its environment. Pilots must regularly calibrate and check their compasses to mitigate the effects of deviation from metallic components and electrical devices, ensuring that their navigation remains reliable.