How does the pitch attitude in a climb typically change when thrust increases at constant IAS?

In a climb, when thrust increases while maintaining a constant indicated airspeed (IAS), the aircraft will see an increase in power available. To understand how this affects pitch attitude, consider the fundamentals of flight dynamics and lift.

When thrust is increased in a climb, more power is available to counteract the drag and maintain the climb. Since the goal is to keep the IAS constant, the aircraft needs to adjust its lift to match the new thrust situation. Increasing thrust while keeping speed constant implies that the aircraft has the ability to maintain its altitude and climb performance without a corresponding increase in drag, which can lead to a decrease in angle of attack.

As the angle of attack decreases, the pitch attitude of the aircraft will also decrease. Essentially, with higher power and the same airspeed, the aircraft can effectively lower its nose attitude because it no longer needs to pull as much to generate the required lift for maintaining altitude. This results in a more level or even descending attitude when compared to the previous climb.

Considering these aerodynamic principles, the correct answer reflects how the increased thrust requires a change in pitch attitude to maintain the aerodynamics and performance of the aircraft.