What can be expected from the ASI/Mach meter during a climb with a blocked pitot probe?

When a pitot probe gets blocked, the airspeed indicator and Mach meter experience issues because they rely on the correct measurement of dynamic air pressure to function accurately. During a climb, the ambient air pressure decreases. If the pitot probe is blocked, it will not be able to measure the increasing altitude's impact on airspeed accurately, leading to a misrepresentation of the aircraft's speed.

In this specific case, as the aircraft climbs, the dynamic air pressure is expected to decrease, but the blocked pitot probe prevents the Mach meter from obtaining an accurate dynamic air pressure reading. Consequently, while the aircraft climbs and true airspeed increases, the improperly calibrated system may register speeds that are artificially inflated compared to the actual conditions. Therefore, during a climb, the Mach meter is likely to indicate a higher value than the true Mach number.

Thus, it is correct to conclude that the Mach meter will over-read during a climb with a blocked pitot probe.