During an enroute descent with blocked pitot system by ice, what airspeed indication can be expected?

When the pitot system becomes blocked due to ice accumulation, it leads to an erroneous airspeed indication. In this situation, as the aircraft descends, the actual dynamic pressure decreases because the aircraft may be gaining altitude in relation to the air that's now moving past it.

Since the pitot tube is blocked, the airspeed indicator doesn't receive fresh static pressure readings but is instead responding based on the stale pressure captured when the tube was not blocked. During descent, as the aircraft's true airspeed increases relative to the surrounding air, the indicated airspeed will show a decrease. This occurs because the blocked pitot system does not account for the change in pressure resulting from the increased altitude loss.

Thus, the expected indication is a decrease in indicated airspeed, which aligns with the principles of how airspeed indicators function under these specific conditions.