CWS-P and CWS-R Problem 737TNG

[Ed Callan 0]

Hello All, This just started....737TNG....whether on a manual approach or an approach using the FMC.....just as the ils is locked in I see a yellow CWS R and CWS P appear under the CMD....Is there something I can enable/disable to correct this?Ed Callan

[Tabs 2,790]

Ed,The AP will get put into Control Wheel Steering mode if you move the flight controls manually while the plane is under autopilot control. I'm not sure what you mean by "manual approach" - if you're handflying with the AP off, there's no way it should be going into CWS. I'd check your joystick calibration and make sure there aren't erroneous signals being sent, as that can cause it to jump from normal AP modes like LNAV/VNAV or LOC/GS to CWS.

[Ed Callan 0]

Sorry by manual I meant manually setting freqs and headings. I dont move my yoke or touch the flight controls but ill try and recalibrate my yoke...thanxEd

[onurksn 1]

Hello Ed,Your problem also occurs when the AP fails to intercept the LOC or the GS. You will have to manually "help" the AP to get into the correct position(CWS R)/altitude(CWS P).It is preferable to intercept the LOC in HDG mode rather then LNAV and make sure you engage APP mode at least one dot above the middle one.I hope I haven't repeated anything you already know.Regards

[Ed Callan 0]

Hi Onur, I have been intercepting the loc from the hdg mode and above the gs but still get the cws message...thanx Ed

[ronzie 21]

The GS indicator must be above center when you intercept and go to APP mode. That does not have I think a relationship to your CW mode question but if this is not what you are doing as stated above in your response you will not capture the GS. Also enable both CMD buttons for max vertical control. If you autoland it is mandatory and will be annunciated on the PFD. Dual CMD mode will not be effective until either 1,000 or 2,000 feet AGL and will be announced on the PFD.If your CMD mode drops out make sure your IAS is correct and flaps schedule for your weight or your trim could be out of range for A/P control at your slower landing speeds.In some weather/location cases I have had vertical drafts cause such pitch variation that the A/P dropped out attempting to stay on the vertical path. The same might be true of crosswinds beyond control authority correction under CMD.

[Ed Callan 0]

thank you

[onurksn 1]

Hi again Ed,Well weather could be the issue, but i'll assume you've already tried it with fair weather.Usually AP goes into CWS mode if you touch your controls or if roll or pitch requires manual intervention. As a last solution, check out the manuals, maybe you might find an answer. It may be a very simple thing you're missing.Happy Landings

[Ed Callan 0]

Thanx Ill keep working on it Ed