Plain English Meaning

When a pilot flying by looking outside accidentally flies into weather where they can no longer see the ground, horizon, or sky clearly, and must suddenly rely on the cockpit instruments to keep the aircraft under control.

Full Definition

An unplanned encounter with instrument meteorological conditions (IMC) by a pilot operating under visual flight rules (VFR), in which outside visual references are lost due to clouds, fog, precipitation, or reduced visibility. It is treated as a serious safety event because the pilot must to flying solely by to instruments, regardless of training or .