Do airline pilots increase thrust when ordered to increase altitude by traffic controllers? Do they simply use flaps, the yoke (or joystick in the case of airbus) and the stabilizers without any increase in thrust. What is the altitude increase sequence or procedure . Do they simply rely on auto pilot and if so does it increase thrust too?
Do airline pilots increase thrust when ordered to increase altitude by traffic controllers
Yes, without increasing thrust the act of ascending would reduce speed.
Do they simply use flaps
No, flaps are not used to climb. They are used to increase the surface area of the wing in order to allow the aircraft to fly at slower speeds (for example, during approach & landing).
What is the altitude increase sequence or procedure
Generally, and put simply, it is increase thrust then raise the nose.
Do they simply rely on auto pilot and if so does it increase thrust too?
They may well use the autopilot to do it all, but some autopilots do not control the throttle so that would be done manually by the pilot while the autopilot controls the rate of climb.
I’ll try my hand at a more ‘scholastic’-aviation approach:
The normal procedure taught in flight school for initiating a climb is P-A-T. That is Power-Attitude-Trim.
You increase power on the engine(s) first.If left alone, the plane will settle (very slowly, google phugoid) into a climb eventually
Because we do not want to wait the few mins or so it takes for the plane to settle into the climb, we use the elevator (via yoke or sidestick) to settle the attitude of the plane directly into a climb position (ie. point the nose higher up). A good pilot will do this without letting the speed climb or drop. ‘Call it pitch-for-speed.
Now the plane is in a different power/attitude and even though the plane is (or should be) at the same speed, a little bit of trimming is required to null the forces on the yoke.
now you can sit back and enjoy the climb.
Leveling off after the climb is a A-P-T.... you guessed: Attitude-Power-Trim. The reasoning for the change of order is that you want to prevent the plane from a nose-up, low-power situation, with speed decaying quickly.
Mind you, in a modern airliner most of these things can be automated via an autopilot/autothrust as described in the other answers.
Most airliners today use auto pilot and auto thrust when flying in level flight or climbing and descending.
The normal sequence for a climb is to enter a new altitude in the flight computer and then engage a climb mode on the autopilot. In any aircraft thrust is usually increased for a climb and decreased for a descent. The Auto-thrust will adjust automatically in most modes to maintain a desired speed and rate of climb. The autopilot adjusts the elevator or stabilizer to climb or descend to the set altitude.