10-06-2005, 03:00 PM
Here at Southwest, we CAN use the autopilot down to about 150FT AGL on a clear day, and 50FT AGL on CAT II ILS minima days. That
doesn't mean we always do (actually, it's much the opposite for approaches... hardly ever used.)
Usually, through rough turbulence regardless of what stage of the flight we're in, we'll use the autopilot on CWS (Command Wheel
Steering) mode. In this mode the pilot can maintain control of the aircrafts control surfaces, however when all pressure is released on
them, the autopilot will maintain that attitude.
For example, If I'm climbing up through some thick cumulus with the autopilot on and in LNAV and VSPEED mode (our usual climb
configuration), and the turbulence is affecting our control of the aircraft, or causing excessive attitudes, we'll flip on the CWS mode
and "semi-automatically" fly the aircraft. If I need 10 degrees of left bank, and 5 degrees pitch up; I manually set the controls where
desired, and the autopilot maintains that setting.
I hope I answered your question alright, if I didn't, let me know and I can elaborate more, or try to help you out.
Oh, by the way. If we've got a bumpy approach to deal with (gusty winds, windshear, low cloud base, etc.) we'll normally use the autopilot
in approach or localizer mode (depending on the type of approach). The autopilot makes flying the plane a lot easier, and can usually
deal with these types of approaches much better than a human pilot. For the really heavy stuff, we'll use the monitored approach
procedures with the autocoupled approach mode engaged (both autopilots on, as if I was setting up for an autoland.). We'll still
disengage them by 50 feet under the minimums (sometimes higher), but that's the closest we'll do to an autoland.
If you have any more questions, feel free to ask here, or start a new thread.
doesn't mean we always do (actually, it's much the opposite for approaches... hardly ever used.)
Usually, through rough turbulence regardless of what stage of the flight we're in, we'll use the autopilot on CWS (Command Wheel
Steering) mode. In this mode the pilot can maintain control of the aircrafts control surfaces, however when all pressure is released on
them, the autopilot will maintain that attitude.
For example, If I'm climbing up through some thick cumulus with the autopilot on and in LNAV and VSPEED mode (our usual climb
configuration), and the turbulence is affecting our control of the aircraft, or causing excessive attitudes, we'll flip on the CWS mode
and "semi-automatically" fly the aircraft. If I need 10 degrees of left bank, and 5 degrees pitch up; I manually set the controls where
desired, and the autopilot maintains that setting.
I hope I answered your question alright, if I didn't, let me know and I can elaborate more, or try to help you out.
Oh, by the way. If we've got a bumpy approach to deal with (gusty winds, windshear, low cloud base, etc.) we'll normally use the autopilot
in approach or localizer mode (depending on the type of approach). The autopilot makes flying the plane a lot easier, and can usually
deal with these types of approaches much better than a human pilot. For the really heavy stuff, we'll use the monitored approach
procedures with the autocoupled approach mode engaged (both autopilots on, as if I was setting up for an autoland.). We'll still
disengage them by 50 feet under the minimums (sometimes higher), but that's the closest we'll do to an autoland.
If you have any more questions, feel free to ask here, or start a new thread.