What gyroscopic instrument needs to be aligned with the magnetic compass?

The heading indicator is a gyroscopic instrument that provides the pilot with the aircraft's current heading relative to magnetic north. It operates by using the principles of gyroscopic precession, which allows it to maintain a stable reference point as the aircraft turns.

To ensure accurate navigation, the heading indicator must be regularly aligned with the magnetic compass, which reflects the aircraft's heading in relation to the Earth's magnetic field. This alignment is typically done either prior to takeoff or during flight, depending on the aircraft's operational procedures.

In aviation, one must be mindful that the magnetic compass can sometimes present errors due to magnetic interference or variations, and hence, the heading indicator serves as a reliable instrument when properly aligned. This process of alignment ensures that flight paths are accurately followed, especially during navigation and when executing turns.

The other instruments mentioned—cockpit display, vertical speed indicator, and attitude indicator—serve different purposes and do not require alignment with the magnetic compass. For instance, the attitude indicator displays the aircraft's orientation relative to the horizon, while the vertical speed indicator measures the rate of ascent or descent. These instruments function based on different principles and do not rely on magnetic reference for operation.