When the static port is blocked, what will happen to the VSI?

When the static port is blocked, the altimeter and vertical speed indicator (VSI) will be affected because they rely on changes in atmospheric pressure to function accurately. The VSI measures the rate of climb or descent by detecting changes in static pressure. If the static port is blocked, the pressure remains constant inside the VSI.

As a result, the VSI will not be able to indicate any climb or descent accurately; instead, it will momentarily 'freeze' and typically remain at the last indicated rate, which often appears as zero. This frozen indication reflects the inability to sense changes in altitude, leading to a misunderstanding of the aircraft's actual vertical speed. Hence, this choice effectively encapsulates the malfunction that arises when the static port is obstructed.