What rate of descent should be maintained with a groundspeed of 500 knots?

To determine the appropriate rate of descent for a given groundspeed, it's important to understand the relationship between the two. A common rule of thumb for estimating a safe descent rate is to divide the groundspeed by a factor that usually falls between 3 and 5. This provides a rough estimate of how many feet per minute (fpm) one should descend at that groundspeed.

In this case, with a groundspeed of 500 knots, applying the rule might typically suggest a descent rate in the range of approximately 1500 to 2500 feet per minute. Therefore, when considering the answers provided, 2500 fpm aligns well with this rule of thumb as it falls within this reasonable estimate for a 500-knot groundspeed.

Maintaining this rate provides a balanced approach, facilitating a safe and controlled descent while ensuring that adequate time is available for the approach to landing, assuming conditions are normal and no extreme maneuvers are required. Higher rates of descent, such as 3000 fpm or 3500 fpm, are often reserved for specific circumstances where a rapid descent is necessary, which may not apply in standard operations.

Choosing a descent rate of 2500 feet per minute maximizes efficiency while maintaining safety margins