A simple experiment:
1.Steady level flight at FL100, speed 250 KIAS.
Increase speed to 300 KIAS while maintaining level, 0 fpm rate of climb.
=> Thrust needs to be increased to increase speed. If you change pitch, you start descending or climbing.
To maintain level, 0 fpm you will need to pitch down as you accelerate. If you maintain pitch you will start to climb. Eventually an equilibrium will be reached where (Thurst - Drag) / Weight = The Rate Of Climb.
Conclusion: Both pitch and thrust affect speed and the rate of climb.
2.Steady stable climb with 250 KIAS and 500 fpm rate of climb.
Increase speed to 300 KIAS while maintaining 500 fpm rate of climb.
=> thrust needs to be increased to increase speed. If you change pitch, the the rate of climb changes.
To maintain 500 fpm you will need to pitch down as you accelerate. If you maintain pitch you will increase the climb rate. Eventually an equilibrium will be reached where (Thurst - Drag) / Weight = The Rate Of Climb.
Conclusion: Both pitch and thrust affect speed and the rate of climb.
3.Steady stable climb with 300 KIAS and 500 fpm rate of climb.
Reduce speed to 250 KIAS while maintaining 500 fpm rate of climb.
=> Thrust needs to be reduced to decelerate. If you change pitch, rate of climb changes.
To maintain 500 fpm you will need to pitch up as you decelerate. If you maintain pitch you will decrease the climb rate. Eventually an equilibrium will be reached where (Thurst - Drag) / Weight = The Rate Of Climb.
Conclusion: Both pitch and thrust affect speed and the rate of climb.
4.Steady level flight with 300 KIAS. Reduce speed to 250 KIAS, keep 0 ft rate of climb.
=> Thrust needs to be reduced to reduce speed while maintaining level flight.
same again
5.Steady decent with 250 KIAS, 500 fpm rate of decent.
Increase speed to 300 KIAS.
=> Thrust needs to be increased to accelerate. Change of pitch changes rate of decent.
and again
6.Steady descent with 300 KIAS, rate of decent 500 fpm.
Slow down to 250 KIAS while maintaining 500 fpm rate of decent.
=> Thrust needs to be decreased to slow down. Change of pitch changes rate of decent.
and again
Conclusion: Thrust controls speed and pitch controls rate of climb or decent.
Conclusion: Where were you in "straight and level" part 2?
Hardly special cases when aircraft do this day in day out. The fact that you invoke these as being exceptions to your conclusion simply demonstrates your conclusion is not a generalised solution.
Its about as valid as saying 'on Fridays its always Friday'.
pb