Final answer:
In a climb, a pitch increase can result in a higher ASI reading because of increased lift and thrust. However, without enough power, this can be a misinterpretation as the actual airspeed might decrease.
Step-by-step explanation:
When an airplane climbs and a pitch increase results in a higher airspeed indicator (ASI) reading, it is due to the plane's increased lift and thrust overcoming the gravitational pull and drag. As the pitch angle increases, the wings generate more lift up to the critical angle of attack. However, if this pitch increase leads to a climb without a proportional increase in thrust, the increase in ASI reading might also be due to a misinterpretation, as the actual airspeed could decrease if not enough power is provided. It is crucial that pilots manage both pitch and power to maintain controlled flight.