Plain English Meaning
It's the feeling of anxiety or stress a pilot can get when flying in clouds or under the hood, relying only on instruments. If left unchecked, it can make flying harder and less precise.
Full Definition
In the context of instrument flight, nerves refers to the heightened state of anxiety, tension, or apprehension a pilot may experience when flying solely by reference to instruments, particularly during early instrument training or in challenging weather. This emotional and physiological response can degrade performance by impairing scan technique, decision-making, and smooth aircraft control if not recognized and managed.