When climbing with a completely frozen pitot tube, what will the ASI indicate?

When climbing with a completely frozen pitot tube, the airspeed indicator (ASI) will reflect a change in altitude rather than a change in true airspeed. This occurs because the ASI measures dynamic air pressure, which relies on the correct functioning of the pitot-static system to differentiate between static pressure and dynamic pressure.

In the event of a frozen pitot tube, the static pressure can still be measured, but dynamic pressure cannot be properly sensed, leading the ASI to behave similarly to an altimeter. As the aircraft climbs, the air density decreases, and since the frozen pitot tube does not allow for dynamic pressure changes to be reflected in the ASI reading, the instrument will begin to indicate an increase in airspeed. This reading is misleading, as it is not providing an accurate representation of the aircraft's true airspeed, but rather an indication based on the change in ambient pressure correlated with altitude gain.

Thus, in this scenario, the ASI will indicate an increasing airspeed falsely due to the malfunction of the pitot tube, highlighting the importance of understanding how instrument systems operate under fault conditions in aviation.