For a constant-rate descent, which instrument serves as the primary for maintaining pitch?

In a constant-rate descent scenario, the primary instrument for maintaining the correct pitch attitude is the vertical speed indicator (VSI). The VSI displays the rate of climb or descent in feet per minute, which is critical for a pilot to maintain a constant descent rate.

When the goal is to achieve a specific descent rate, pilots adjust the aircraft's pitch to match the desired vertical speed depicted on the VSI. If the rate of descent is too high, increasing the pitch will reduce the descent rate, while lowering the pitch will initiate a steeper descent if needed.

Other instruments play supportive roles in this scenario. The airspeed indicator primarily informs pilots about the aircraft's speed relative to the air, while the manifold pressure gauge is more pertinent for managing engine performance rather than directly influencing vertical speed or pitch control. The attitude indicator, while crucial for maintaining the aircraft's orientation, does not provide specific data on the rate of descent, thus making the VSI the key instrument for this particular aspect of flight.