What does a magnetic compass help to set in an aircraft?

A magnetic compass is a fundamental navigational instrument in aviation. Its primary function is to provide the pilot with the aircraft's heading relative to magnetic north. This heading information is crucial for navigation and is used to set gyroscopic heading indicators, which are more stable and accurate for maintaining directional flight than a magnetic compass alone.

Gyroscopic heading indicators rely on the principles of gyroscopic precession and help to display the aircraft's heading consistently. While a magnetic compass can be affected by external magnetic forces and is less stable during maneuvers, the gyroscopic heading indicators provide a more reliable reading, especially during turns or turbulence. Thus, the magnetic compass directly aids in setting these indicators, enabling pilots to maintain a clear course during their flight.