What does the phrase "flying the needles" refer to?

The phrase "flying the needles" refers specifically to the practice of adjusting one’s flight path based on navigational instruments, particularly those that provide information on heading, course deviation, and other relevant data. This method is essential for instrument flying where pilots rely on instruments rather than visual references to navigate.

When pilots use instruments such as the horizontal situation indicator (HSI) or the course deviation indicator (CDI), they "fly the needles" by interpreting the information presented to make precise corrections to their heading and maintain the planned course. This process is crucial in conditions where visibility is low, and visual references cannot be relied upon.

The other options essentially refer to different methods of navigation that do not involve adherence to the precise navigational cues offered by instruments. For instance, flying without navigation aids would imply a lack of reliance on instruments altogether, while following visual flight rules entails navigating by visual means rather than instruments. Navigating solely using maps and charts is also a more traditional method of navigation, distinct from the precision navigation provided by modern cockpit instruments.