Hello PMDG team,On the new 737NG's will CWS (Control Wheel Steering) be simulated?Thanks-Nick

I hope so...if they model the autopilot with the datastream comming from the FCC's who got it from the AFDS and Autothrottle system, it shouldn't be that hard to make the FCC feed straight from flight-parameters...Cheers

HiWhat exactly is control wheel steering? I understand it is a mode of the AP, but what does it do?ThanxAlaister Kay

So, Lenny,if it's not that hard, what exactly do I tell my FCC that my yoke position is? Remember, Control Wheel Steering is, essentially, thatI place my control wheel (yoke, column, whatever) into a set position, then the FCC "keeps" it there, in terms of pitch/bank. Which yoke position would that be, when your yoke or joystick has no force feedback to keep the axes there?You can see, this is not simple to model (I tend to think it's downright impossible, really).Cheers,

Hi Lefteris!I don't think it's impossible (but it won't be as in the real plane)Make the AP hold the pitch/bank the pilot sets as long as he adds pressure to the stick. As soon as the stick starts to move the neutral position (because the user has let go of the stick), the AP will continue to hold the pitch/bank that was set previously. You'd have to inhibit the joystick from its deflected position to the neutral position to stop the plane from moving along with stick deflection back to neutral...I just wonder how difficult it would be to model this?Another option: you have a CWS switch on the yoke like on GA aircraft, as long as you press this button, the AP "follows" stick deflection, and, when you let go, the joystick is "disconnected" and the AP will maintain the pitch/bank that was set while the switch was pressed...Regards,Mark

Mark,I can't say with absolute certainty on the 737, but I can confirm that the 757/767/777 and 747-400 are losing the CWS mode. suspect Wallace could confirm this :-) All of the A/C we have delivered in the last 2 years have had the buttons removed and the new Collins MCP doesn't even have a hole for them anymore. I think the biggest problem with simulating CWS is that it would have to be tied to a force feedback system in order for it to work properly. The system on the A/C relies on the feedback from the control column sensors to know where to keep the control wheel positioned, Kind of hard to do with a joysick in this day and age. What you would have to do to make it work is hold your joystick, or control wheel in the same position to fake out CWS. Don't know about you but I really don't need that kind of extra work when I'm flying. From what I understand, CWS was really an early A/P function to help control an A/P from over-reacting to turbulence or other rapid fluctuations, Today's A/P systems are so complex and so smooth I can honestly say I haven't ever seen a pilot on any of our CWS equipped A/C use the function in over 10 years of riding Jumpseat. RegardsPaul:-cool

Hi Paul!From what I understand, CWS is a basic default mode in the 737. While in the other planes CWS would never be used by itself, I believe CWS is the mode that the plane enters when you activate an A/P without having set any other modes for the F/Ds (ie FD's off). Thus it makes CWS a little more important on the 737 than on the other aircraft, or am I mistaking here?Regarding how to make this work in the sim, yes, that's a big problem. What is your opinion of my ideas?They just came from the back of my head and I'm curious what the people in the loop think about it!Regards,Mark

Mark-if it's not as in the real plane, be assured, we won't do it. In my opinion, we either do it as it would be in reality, or we don't do it at all... otherwise, we're compromising the reality we always strive for...Just to give you an example, in our current tests, the AutoThrottle mechanism behaves within the specs / parameters of the real thing (in some cases, it even behaves more smoothly than the real thing ;-))) ).Cheers,

Hi Lefteris,I completely understand your point! Ok so that rules out my second idea :-)What about my first one? ;-)Come to think of it, it ain't completely realistic either...Oh well, as developers it's your job to surprise us :-)And yes, I'm waiting ;-)RegardsMark

Mark-that wouldn't work either- think about it: Which position, exactly, is the one we should decide the pilot stopped "intending" to hold for CWS? What if he went, say, 10degrees forward on the yoke, then wanted to go back 2degrees?You can't tell...Unless someone proves to me this can be done realistically (and without a force feedback yoke, this will not be easy!), I am leaving CWS out of this release.Cheers,

Lefteris,Well I doubt that there is any way to make it truly realistic, as we don't have the hardware for this.Let's look at the spring-loaded joysticks."What if he went, say, 10degrees forward on the yoke, then wanted to go back 2degrees?"After returning the stick to the center position, you could move the joystick 2 degrees into the opposite direction.While the real CWS holds the coloumn in a set position, would it be so unrealistic if the joystick would remain in the center position, and the AP would continue to fly the last commanded pitch/bank attitude? You still need manual input to change the attitude, just as in real life. I don't think it's a too big a sacrifice.Of course, I understand that it won't make it to the first release, but maybe you can think (and experiment) with this idea?Why model the stall warning? We don't have stick shakers... :-)(I'm not saying that you shouldn't model the stall warning, just that sometimes we just have to make compromises...)Regards,Mark

Mark-hey- interesting discussion! ;-)The reason this would not work is simple: Control-Wheel Steering works when the pilot moves the control column. (S)he sets it to the appropriate position, and the FCC decides that it has to keep the pitch/bank the aircraft has, at that position.In the FS world, the sim-pilot sets the yoke at a position, and the yoke returns to a neutral position (sometimes). Other times, the yoke returns to a close-to-neutral, but not-exactly-the same position, etc.etc.What happens if the sim-pilot wants CWS to return to 0 degrees pitch / 0 degrees bank?There's just absolutely no way for me, as a programmer, to decide which position is the "FCC-ok-this is the one" position... if you think about it a bit more carefully, you'll end up agreeing with me on this. ;-)Cheers,

Lefteris,"hey- interesting discussion"You bet!!What we'd be looking at would be something similar to the FBW system in airbuses...Anyhow, you would probably have to set up a null zone which the AP could then interpret as a coloumn which has been let go of."What happens if the sim-pilot wants CWS to return to 0 degrees pitch / 0 degrees bank?"I don't really see a problem here? You basically "select" an attitude with the joystick and once the AP sees the joystick move to the neutral position, it is disconnected and the FCC maintains the current attitude.Unfortunately, I'm not programmer but to be totally honest, I can't really see the problem (*).Or did I overlook something?(*) the question is, is all this worth it? I assume this would require A LOT of work, especially with the nullzone setting (extra module etc). Well maybe if you are releasing special addons for the package (HUDs etc) and you run out of idea and are bored ;-) you could look into this :-)Regards,Mark

So,how do you distinguish between:a) User selected 7 degrees pitch-up, then went yoke-neutral, so CWS picked up the fact that they want to be at 7 deg. pitch up.:( User selected 7 degrees pitch-up, then let go of the yoke, which went through all positions from 7 degrees, back to just-before-null-zone, so CWS picked up the fact that they want to be at 0.001 deg. pitch up.c) User selected 7 degrees pitch-up, then changed their mind (ATC told them to hold current altitude), so went back to neutral position, which is the same as the null-zone, so CWS has NO CLUE what they want to do! ;-)See the problem? ;-)

Hmm not really :-)What if we look at the deflection as relative, and not absolute?Ok let's say we want a 7