What should a pilot do when faced with a rapidly increasing altitude along with a high rate of climb and decreasing airspeed?

When a pilot is faced with a rapidly increasing altitude, a high rate of climb, and decreasing airspeed, adding power is the appropriate action to take. This scenario indicates that the aircraft may be approaching a situation where it could stall, typically characterized by a high angle of attack coupled with insufficient airspeed. By adding power, the pilot can maintain the necessary lift and prevent the aircraft from stalling. The increase in engine power helps to stabilize the flight by providing the thrust needed to maintain airspeed while continuing to climb safely.

Contrary to this, decreasing engine power could exacerbate the situation by reducing lift and further decreasing airspeed, increasing the risk of a stall. Leveling off immediately might prevent further altitude gain, but it doesn't address the airspeed issue. Reducing pitch dramatically would also likely result in a further decrease in airspeed and could lead the aircraft into a stall if not managed carefully. Therefore, maintaining adequate airspeed by adding power is crucial in this scenario.