What effect does Pitot blockage have during a climb?

When a Pitot tube becomes blocked, it typically results in the airspeed indicator reading erroneously. During a climb, the pressure in the blocked Pitot tube does not change in response to the dynamic pressure changes caused by the aircraft's motion. Since the aircraft is climbing, the static pressure is decreasing, which affects the indicated airspeed.

In the case of Pitot tube blockage, the airspeed indicator will show a reading that appears higher than the actual airspeed because it is not receiving the correct measurement of total pressure. The instrument relies on a balance between dynamic pressure (from the airflow) and static pressure to provide an accurate airspeed reading. Thus, during a climb, the combination of static pressure decrease and the blockage leads to an over-reading of airspeed.

While it's essential to understand that the interpretation of the airspeed can be complicated by the additional dynamics of the flight situation, the fundamental principle concerning the effect of a blocked Pitot tube during a climb is that it misrepresents the true airspeed, leading to an over-read indication.