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AT
Autothrottle
Settings are MAX REV, MIN REV, IDLE, TO/GA, and MAX. Thrust limiting is based on the active N1 rating, while speed limiting is based on low speed and maximum structural speed limits. Gust compensation is provided. A thrust lever difference of half the lever handle diameter is allowed. If the FADEC detects an engine shutdown or failure, the active throttle remains in autothrottle mode.
Engagement
| Ground | AT is working |
| AT TO armed (AT button on the GP) | |
| Thrust levers above 50° TLA | |
| Inflight | AT is working |
| AT button on GP is pressed | |
| At or above 400' agl |
Disconnection
- AT disconnect button
- AT button on GP
- TLA difference > 8°
- AT monitor tripped
- Required system parameter invalid
- On ground (WOW), thrust levers idle, AT in RETD
Modes
| Annunciation | Description | Associated Modes |
| SPDT | speed on thrust | FPA, VS, GS, ALT, ASEL, FMS speed |
| SPDE | speed on elevator, flight level change thrust control | FLCH, OVSP, FMS speed |
| TO | takeoff thrust | TO |
| GA | go around thrust | |
| HOLD | takeoff thrust hold | TO and > 60kts and < 400' agl |
| RETD | retard | FLARE (not when RAT is deployed and landing with flap 3) |
| LIM | limited thrust | SPDT |
| OVRD | override |
EICAS messages
AT FAIL