During a climb to cruising level with a constant pitch attitude and max climb thrust, how do the flight path angle, angle of attack, and IAS change?

In a climb to cruising level with a constant pitch attitude and maximum climb thrust, several aerodynamic principles come into play that influence the flight path angle, angle of attack (AoA), and indicated airspeed (IAS).

As the aircraft climbs, maintaining a constant pitch attitude while applying maximum climb thrust typically results in an increase in the flight path angle. However, at some point in the climb, especially if the aircraft reaches a certain altitude or weight limit, maintaining the same pitch attitude might lead to a decrease in the flight path angle. This means that while the aircraft is climbing, the vertical component of the aircraft's trajectory may become smaller relative to the horizontal component as air density thins and less lift is generated given the same AoA.

The angle of attack is likely to increase during the climb due to the need for more lift to counteract the weight of the aircraft. As the aircraft climbs higher, it may require a greater angle of attack to maintain the same rate of climb because of the reduction in air density which provides less lift for a given airspeed.

Indicated airspeed (IAS) is generally expected to decrease during the climb due to the aircraft’s performance characteristics and the elevation gain. In a climbing scenario where maximum thrust is being utilized,