RandomPerson8008
27th Feb 2022, 05:32
For some reason, I get asked this a lot: What will the 747-8 autothrottle do if left on during a manual (autopilot disconnected) landing?
First off, it is mandated by the FCOM landing procedure to disengage the autothrottle no later than 100 feet height above touchdown during a manual landing at my employer. This is likely because we have a mixed fleet of -8 and -400. The 747-400 autothrottle will maintain SPD flight mode annunciation all the way to touchdown, meaning it will add thrust to maintain Vapp in the flare, and usually cause a long landing if left on during a manual landing, verified in the simulator. Additionally the FCTM recommends disconnecting both autopilot and autothottle at 1-2 NM from the threshold or 300-600 feet above field elevation during a manual landing.
Does anyone know what the 747-8 will do with the autothrottle in the event that a pilot forgets to turn them off, or intentionally leaves them on during a manual landing for some reason? I am told that the -8 will retard the thrust levers to idle at approximately 25 feet, similar to an autoland, but I do not have a 747-8 simulator to try it out in. I supposed I could try it in the differences trainer, but I have low confidence in its accuracy.
First off, it is mandated by the FCOM landing procedure to disengage the autothrottle no later than 100 feet height above touchdown during a manual landing at my employer. This is likely because we have a mixed fleet of -8 and -400. The 747-400 autothrottle will maintain SPD flight mode annunciation all the way to touchdown, meaning it will add thrust to maintain Vapp in the flare, and usually cause a long landing if left on during a manual landing, verified in the simulator. Additionally the FCTM recommends disconnecting both autopilot and autothottle at 1-2 NM from the threshold or 300-600 feet above field elevation during a manual landing.
Does anyone know what the 747-8 will do with the autothrottle in the event that a pilot forgets to turn them off, or intentionally leaves them on during a manual landing for some reason? I am told that the -8 will retard the thrust levers to idle at approximately 25 feet, similar to an autoland, but I do not have a 747-8 simulator to try it out in. I supposed I could try it in the differences trainer, but I have low confidence in its accuracy.