Speedbird744,
On the airbus you push the power levers up to TOGA (take off/go-around) or the FLEX (flexible) gates on takeoff, bring them back to the CLB (climb) gate at 1500 feet and leave them there until the aircraft tells you to retard them when you are in the flare.
The power levers are not directly connected to the engines, when the A/THR (auto thrust) is on (normal procedure) and the thrust levers are in the CLB gate it will power up the engines if you have to climb, apply the correct amount of power to maintain altitude and airspeed in the cruise, and reduced thrust (to idle if necessary) on descent.
When the A/THR is connected the crew does not move the thrust levers at all during flight. The airbus manual describes the thrust levers as being the way pilots interface with FMGC (flight management guidance computer) and the FADEC (full authority digital engine control system), others just see them as being switches.
The A/THR has three modes, SPEED/MACH, THR (CLB, IDLE), and RETARD (IDLE).
These A/THR modes are brought to the attention to the crew by displaying messages like TOGA, MAN FLX, THR CLB, CLB SPEED, MACH, IDLE, on the PFD (primary flight display-the one with the electronic A/H), these are what is known as FMA’s (flight mode annunciators) and they tell the crew what the A/THR is doing in all phases of flight.
Others have talked a little about “open descent” this is the AP-FD (auto pilot – flight director) vertical mode, not an A/THR mode. The A/THR modes are on the top left of the PFD. The A/THR can be in IDLE mode when the aircraft is in DES (descent) or OP DESC, EXP DES, or FLARE AP-FD modes.
The thrust lever setting, and other engine parameters are on the upper ECAM screen. If you get a chance to see the upper ECAM on this video you will see a little white doughnut on the N1 (top row), this is the TLA (thrust lever angle) or more simply the position of the thrust levers, the actual N1 is displayed as both a numeric value in the center and the sweeping arm on the N1 gauge. You will notice that when the A/THR in armed, the TLA may not reflect the position of the N1, in most cases it will be at the CLB gate, and the N1 sitting further back.
