Autopilot CSS vs ATTH

This is a quote from the wiki, but the same text is in the manual:

"The most basic mode of the AFCS is control stick steering, or CSS. CSS will attempt to maintain the pitch and roll of the aircraft without manual stick input. Roll input is dampened and pitch input is severely dampened. Forward or aft stick deflection beyond a certain point will disengage CSS. CSS is engaged manually by pressing the UFC ON/OFF button in the A/P menu and also engages with all other autopilot modes. In the A/P menu, there are five main autopilot modes, toggled by pressing the option select button next to their window."

So what is the difference between the above CSS mode and the Attitude hold mode?

CSS doesn’t just work in level flight, you can activate it in climbs and descents as well.

CSS doesn’t just work in level flight, you can activate it in climbs and descents as well.

ATTH works as well in climbs/turns etc. Up to +45° pitch and +70° bank angle, but the AP flies the airplane without any possible manual control input.

CSS, (ControlStickSteering) as the name implies, still leaves you in control of the airplane. Inputs are just heavily dampened.

Very similar to the CWS in e.g. the DC-10 and remotely comparable to manual flying in a Viggen or an A320.

ATTH works as well in climbs/turns etc. Up to +45° pitch and +70° bank angle, but the AP flies the airplane without any possible manual control input.

 

CSS, (ControlStickSteering) as the name implies, still leaves you in control of the airplane. Inputs are just heavily dampened.

Very similar to the CWS in e.g. the DC-10 and remotely comparable to manual flying in a Viggen or an A320.

Derp, I missread the original post

Much appreciated guys! I will try it again, now that I know what to look for.

ATTH works as well in climbs/turns etc. Up to +45° pitch and +70° bank angle, but the AP flies the airplane without any possible manual control input.

 

CSS, (ControlStickSteering) as the name implies, still leaves you in control of the airplane. Inputs are just heavily dampened.

Very similar to the CWS in e.g. the DC-10 and remotely comparable to manual flying in a Viggen or an A320.

I've tried it, but they look and feel the same to me. At least how they are implemented in DCS.

Both are steerable and maintain bank and pitch. Both disconnect about the same time with hard stick inputs.

Anyone have a different experience? It's not really an issue, just curious.

So what is the difference between the above CSS mode and the Attitude hold mode?

Search for flight manuals online suggests that CSS will maintain magnetic heading, NOT roll angle, if the roll angle is less than 5 degrees when engaged, and that roll inputs (whether stick or trim hat) in this configuration adjust heading, not roll. Same source says that CSS maintains roll angle if the angle exceeds 5 degrees when engaged, and in this case it operates just like ATTH. In contrast, ATTH always maintains roll angle. I have no idea if this distinction is modeled in the sim. I'm not near my rig to try it out.

I did some tests and it seems you are right. CSS reverts to 0 degrees roll when roll is smaller than 5 degrees. ATTH maintains ANY roll, even if 1 degree.

In CSS mode, if there is wind, it seems to auto correct to maintain current heading when at 0 roll. (time acceleration and slow speeds really show it)

ATTH just starts to drift away.

So i think you're spot on, thank you!

In CSS mode, if there is wind, it seems to auto correct to maintain current heading when at 0 roll.

This doesn't make much sense since wind doesn't alter the heading. It only changes the track over ground...

Just to clarify, ATTH, HSEL, BALT, RALT and CPL are autopilot submodes. The AP maintains altitude, heading, etc. and CSS allows you to 'interfere' with the AP modes without disengaging the AP.

If you are e.g. in BALT (AP on) and you start to climb by using back pressure or trim, you are using CSS and BALT will change to ATTH.