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Guest earendil1234

CWS Mode in B747-400

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In 737 Autopilot we all know that we have this CWS mode autopilot that will hold the aircraft attitude inputted by the pilot from the stick. I feel this mode is very useful especially when the pilot controls the lateral navigation using the CWS while longitudinal altitude is hold by the autopilot or vice versa, like during a non-precision approach for example. It is much faster for the crew to respond laterally by moving the yoke rather than turning the heading selector knob, beside like during a DME arc approach, it is very difficult for the crew to keep on calculating to which heading the aircraft should fly. Meanwhile, we would like the autopilot to handle the altitude control, so that every time we bank, the aircraft could pitch up automatically to maintain altitude. Do you have such luxury in 747? Can you do it in 744 (PMDG model especially)? I know that there is no CWS mode in 744, What is the similar mode in 744?

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I don't believe any 744s have CWS or an option for it. It was an option for 742s though. To be honest, most pilots don't want to have anything to do with CWS. Some of them actually hate it or have been trained/told to avoid it. You could probably say that it never caught on and now it has become a thing of the past. I'm kinda surprised the 737NG offers it as an option. I even saw someone say the CWS on the UPS MD-11s for roll was disabled.In the 744, you are gonna have to fly in manual or totally AP, no "in between" modes.

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Here's part of a discussion I was reading on the MD11 CWSTh MD-11 has optional full-time CWS. All it does is hold pitch and roll if you let go of the controls. It is overridden by 3 pounds on the yoke in either direction.Unfortunately, if installed, you cannot turn it off without killing the autothrottles or constantly holding in the thumb disconnect button. It makes the plane handfly like a pig on ice, due to constantly having to break that 3 pound threshhold to make any input. I hate it, and most carriers did not purchase it.Is this part of the company options on the PMDG MD11? I cant remember.Rob

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I don't believe any 744s have CWS or an option for it. It was an option for 742s though. To be honest, most pilots don't want to have anything to do with CWS. Some of them actually hate it or have been trained/told to avoid it. You could probably say that it never caught on and now it has become a thing of the past. I'm kinda surprised the 737NG offers it as an option. I even saw someone say the CWS on the UPS MD-11s for roll was disabled.
I see. So, I guess, no luck that there is no "in between" modes in 744. I still don't understand why the pilots are being told not to use it? Sometimes an attitude hold is a very useful autopilot. Let's say you are making a hold, to turn with constant 30 degree bank, it's very easy to just bank until 30 degree and let the attitude hold mode hold that bank angle. Or during a nonprecision approach like I have just mentioned above.I mean, if airbus uses FBW and the pilots love it, why can't they love Boeing's CWS?

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I see. So, I guess, no luck that there is no "in between" modes in 744. I still don't understand why the pilots are being told not to use it? Sometimes an attitude hold is a very useful autopilot. Let's say you are making a hold, to turn with constant 30 degree bank, it's very easy to just bank until 30 degree and let the attitude hold mode hold that bank angle. Or during a nonprecision approach like I have just mentioned above.I mean, if airbus uses FBW and the pilots love it, why can't they love Boeing's CWS?
From all that I heard and read, the previous post says it all...Pilots don't like it and most avoid it like the plague. Vincent

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But why don't they like it or avoid it like plague?Adhika

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But why don't they like it or avoid it like plague?Adhika
Adhika, You may wish to read the pros and cons for yourself. The previous thread provided a short answer to a somewhat complex question. It is a good answer. Sometimes experience w/ a vehicle will give you a better reason for the like and dislikes of some feature or lack of! Study up on the system as it is found in a particular aircraft and then surf the net for discussions by pilots and/or articles. Happy flying Vincent :(

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Adhika, You may wish to read the pros and cons for yourself. The previous thread provided a short answer to a somewhat complex question. It is a good answer. Sometimes experience w/ a vehicle will give you a better reason for the like and dislikes of some feature or lack of! Study up on the system as it is found in a particular aircraft and then surf the net for discussions by pilots and/or articles. Happy flying Vincent :(
P.S. I have worked for several airlines which although they were not flying 747's prohibited the use of the auto pilot. The Chief Pilot told those who questioned it, "we want YOU to fly the plane" some of these hops were 2 hours or more IFR etc. so sometimes the answer can be as simple as that! Vincent

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Thanks Vincent. I see your point. Although I agree that manual flying is sometimes necessary, but then, I do feel that there is a need for this redundancy in the flight autopilot. In an emergency situation, anything that could reduce the pilot's workload is helpful, I believe. The discussion has extended itself to a flight system, though. I hope it still can stay in the PMDG support forum.Adhika

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Thanks Vincent. I see your point. Although I agree that manual flying is sometimes necessary, but then, I do feel that there is a need for this redundancy in the flight autopilot. In an emergency situation, anything that could reduce the pilot's workload is helpful, I believe. The discussion has extended itself to a flight system, though. I hope it still can stay in the PMDG support forum.Adhika
One incident comes to mind here when speaking of acrft automation. China Airlines 747 enroute to LAX almost became an accident due to crew not following procedures and not taking immediate control of the arcft by manual means. This is somewhat off the track maybe, but there is a price to be paid with automation and the airlines and others are still dealing with the problems. It is far to easy for crews to get "relaxed" for lack of a better word on flights as computers take care of most of the workload. Then w/out warning something strange happens and it's catch up time. There is an old saying, you want to be 5 minutes ahead of where you are going. It is a very complex issue AUTOMATION and HOW MUCH is to MUCH. I think aviation is in that middle ground at the moment where the old methods are shall we say butting heads with the new. There is much to be said about both sides and only time and experience will find the true medium. I think you will find that when it comes to installing equipment/systems which "helps the crew" the airlines as well as regulatory agencies will always place safety first and not convinence. Not all pilots/human beings are equal in skills or decision making abilities when things are in doubt and hence the introduction by UAL back when of CRM. We could have a long discussion on this but this probably is not the place. I have a number of years at all levels in the industry with many carriers, I am not an expert, experience has given me my thoughts on certain issues and at least on this one I am of the opinion that you either fly the plane or leave it on autopilot, don't mix things, it may at some point come back to bite you I refer you to the thread above in regards to the MD-11 and CWS and the potential problems of such a system with all that you currently know. Stay high and stay alive....Vincent

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Adhika
Edit to the previousOne incident comes to mind here when speaking of acrft automation. China Airlines 747 enroute to LAX almost became an accident due to crew not following procedures and not realizing what the automation was doing w/ respect to the situation they were in and then taking immediate control of the arcft by manual means. This is somewhat off the track maybe, but there is a price to be paid with automation and human beings and the airlines and others are still dealing with the problems. It is far to easy for crews to get "relaxed" for lack of a better word on flights as computers take care of most of the workload. Then w/out warning something strange happens and it's catch up time. There is an old saying, you want to be 5 minutes ahead of where you are going. It is a very complex issue AUTOMATION and HOW MUCH is TOO MUCH. I think aviation is in that middle ground at the moment where the old methods are shall we say butting heads with the new. There is much to be said about both sides. Automation will someday replace the human factor entirely that I have no illusions about. Pilots will argue otherwise but the writing is on the wall. You will find that when it comes to installing equipment/systems which "helps the crew" the airlines as well as regulatory agencies will always place safety first and not convinence, so the argument at some point will be what is the cause of accidents and the such? Pilots or automation. Not all pilots/human beings are equal in skills or decision making abilities when things are in doubt and hence the introduction by UAL back when of CRM. We could have a long discussion on this but this probably is not the place. I have a number of years at all levels in the industry with many carriers, I am not an expert, experience has given me my thoughts on certain issues and at least on this one I am of the opinion that you either fly the plane or leave it on autopilot, don't mix things, at some point it will come back to bite you I refer you to the thread above in regards to the MD-11 and CWS and the potential problems of such a system with all that you currently know. Stay high and stay alive....Vincent

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