In the Northern Hemisphere, what will a magnetic compass indicate if an aircraft is accelerated while on an East or West heading?

When an aircraft is accelerated while on an East or West heading in the Northern Hemisphere, the magnetic compass will indicate a turn toward the North. This phenomenon occurs due to magnetic compass principles, particularly the effect of acceleration and the Earth's magnetic field.

In the Northern Hemisphere, when the aircraft accelerates, there is a tendency for the compass to show a turn towards the North because of the change in relative motion. The compass relies on the orientation of the magnetic field and the forces acting on it. As the aircraft speeds up, the compass card is subject to inertia, causing a temporary error that results in a northerly deflection. This is known as the "acceleration error."

This behavior is consistent with how magnetic compasses function, where the inertia may lead the compass to point inaccurately during changes in speed, including acceleration and deceleration. Understanding these principles is crucial for pilots to correctly interpret compass readings during flight maneuvers, particularly in an environment where navigation relies heavily on magnetic headings.