Thanks for the reply Chris.I think i see what i'm doing wrong, reading through your explanation, the autopilot isn't like on a Boeing. The ALT SEL won't make the aircraft climb or descend, you have to trim it manually to initiate the climb/descent, ALT SEL will level the aircraft out at the altitude, when you reach it. Then change to ALT to keep you at the required altitude.Thanks for the very useful explanations, actually better than the manual.Happy Simming Dave quote name='ckyliu' timestamp='1282260338' post='1813933']May I be so bold as to you run you through the relevant buttons on the glareshield briefly:* ALT - This is altitude hold mode, it will maintain your present altitude only. It will NOT climb or descend you.* ALT SEL - This is altitude capture mode. Its function is very simple; it engages ALT mode when you reached the preselected altitude visible on the EADI. It performs no other function, again it will NOT climb or descend the aircraft for you.* IAS - This is speed hold mode, it will hold the aircraft's present speed by adjusting pitch as necessary. If you are in level flight with this mode engaged and reduce power, the aircraft will nose down to maintain speed at target. Conversely, if you increase power, the nose will raise lower speed back to the target. Please note the target speed is NOT any of the bugs on the EADI, the target is your speed when the IAS button is engaged. The target can be adjusted by using the thumbwheel located on the pedestal.* VS - This is vertical speed hold mode, it holds the aircraft's present vertical speed. Again, the target value can be adjusted with the thumb wheel on the pedestal. Therefore, in order to climb or descend via autopilot you must use IAS or VS modes. In conjunction with those modes, if you would like the aircraft to level off at a predetermined altitude, use ALT SEL. To maintain level flight use ALT. Hope this helps,Chris.