Which instrument is crucial for navigating when the visibility is poor?

The navigation display is crucial for navigating in poor visibility conditions because it provides critical situational awareness to the pilot. This instrument integrates various navigation information, including the aircraft’s position, flight path, and waypoints, allowing the pilot to visualize the route and make informed decisions even when external visual references are lacking. In situations where weather conditions affect visibility, such as cloud cover, fog, or heavy precipitation, relying solely on visual cues becomes inadequate or impossible. The navigation display helps pilots maintain situational awareness by synthesizing data from various sensors and systems, such as GPS and other navigational aids, ensuring safe and accurate navigation despite the challenges posed by poor visibility.

Other instruments like the vertical speed indicator, altitude indicator, and airspeed indicator provide essential flight data but do not assist in navigation directly; therefore, they are less effective in conditions of low visibility.