Autopilot issue (CWS R and CWS P)

Question

Hello there

I need some help. :-) I know I am a newbie that possibly mixes up a few things. :-) So please do not be too hard on me. I have found a few similar problems in the net, but I did not understand the solutions proposed. Here is what I struggle with:

When I am flying on autopilot (CMD on, Alt Hold or vertical speed on, LNAV engaged), I sometimes accidentally click the mouse and start pitching the aircraft down or up.  After having it stabilized, I often notice that PFD reads CWS R and CWS P in amber color. This is also when I am unable to turn on the "altitude hold" or "vertical speed" button on again. It just won't engage. If the plane is climbing in that very moment, I simply cannot make it stop. Even if it reaches the altitude dialed in. What can I do? Why is this happening?

Bonus questions for all you pilots :-): When flying an ILS on autoland, with correct frequency and course set, it has sometimes happened that the aircraft did not follow the glidescope even if I pressed the "approach"-button. Is that because I did not intercept at the correct altitude? What are the tolerances for the plane to follow the glidescope correctly?

Thank you very much! Have an awesome day!

Adrian

Comments

Hello guys...

I have a problem about the stability of the aircraft. When I start to descend and controlling flaps as the speed decreases, after 10-15 degrees of flaps, aircraft tends to bank to right at almost 90 degrees and dives. This happens both in A/P or manual control. Am I using a MAX  ? xD I need to apply full opposite control to stabilize. During this on screen I sat CWS P and CWS R written as yellow. Can you please help me I can't land.. I'm still flying.....

Answer 1

CWS

By applying pressure on the controls (or you’ve moved the mouse in your case), it will cause the autopilot to enter CWS mode.  In Control Wheel Steering modes, the A/P will attempt to hold the pitch and roll that the yoke was last set for, even after the pressure’s been released.  That’s what the “CWS-P” and “CWS-R” are telling you.  If the sim is implemented correctly, the CMD button light should also go Off, and the CWS light should automatically be switched on to announce the current A/P mode.  As long as movement/pressure are kept on the control, the A/P will remain in that particular (one or both) CWS mode.  You need to somehow get the mouse to “release pressure” on the yoke before you can re-engage ALT or HDG (CMD mode).

GLIDESCOPE

For the A/P to follow the glidescope, the aircraft has to first intercept the G/S.  And before it can intercept the G/S, it has to approach (get into range of) the G/S.  You would want to approach the G/S from below, along the localizer.  An unfilled diamond on the G/S tape indicates the aircraft is not in range.  As you get into range, the G/S diamond will begin to move toward the middle.  The diamond will turn solid magenta, that’s the time to hit the APP button to capture the G/S.

Comments

Thank you very, very much. Finally I start to understand why and how it works.

I have another question, if anyone knows: I often encounter a problem when climbing to cruise level using the V/S speed bug. This often happens when I accelerate to speeds like MACH 0.7 at the same time: The plane climbs and the altitude hold-light goes on. But instead of holding the altitude, the plane continues climbing at a very steep vertical speed. Why is that?

Thank you and have a nice day!

Adrian

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I do not know why the aircraft would continue to climb.  Perhaps simply be a bug in the modeling of the particular aircraft (don’t know what you’re flying).  I suspect that you may have already answered your own question—the high climb out speed.  Mach 0.7 is rather excessive for the climb.  Who knows, maybe that has induced some instability for the A/P? 

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hi there.

I fly the standard 737-800 that comes with X-Plane 11.

I had the same problem yesterday at crusing altitude of FL330. As soon as I went over Mach 0.74, the plane startet to climb... Even tough it was on Alt-hold.

My undrstanding of this ist that due to the high speed, I get more lift...

Can anyone confirm?

Adrian

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The behavior and accuracy of the sim is largely dependent on the implementations for its flight model and autopilot etc.  The default aircraft come with X-Plane typically are less developed.  You should consider trying out the Zibo Mod B738.  It is superior to the default B738 in every way.  Though it will require more CPU & GPU power.