What does Control Stick Steering (CSS) Mode mean?

[tifafan]

Find it in Changelog,but don't know what it is....

[Bunny Clark]

CSS is an autopilot function which allows you to change the commanded attitude hold either by moving the stick or with the trim hat. 

 

I'm a bit confused what the patch notes refer to, as it's been implemented for ages. Though there was a bug before where using the trim hat for CSS would throw your trim irrecoverably out of wack. 

[Pieterras]

@Bunny Clark It was and it wasn't.. The pitch when controlled with trim would keep the aircraft in a trimmed stated for that pitch setting, instead of returning it to neutral, when CSS was cancelled  

[Bunny Clark]

3 minutes ago, Pieterras said:

@Bunny Clark It was and it wasn't.. The pitch when controlled with trim would keep the aircraft in a trimmed stated for that pitch setting, instead of returning it to neutral, when CSS was cancelled  

Yup, that would be the bug I was referring to. Just checked it again, and it still does that. So I'm really confused what changed today ...

[Mnf]

AFCS
The Automatic Flight Control System (AFCS), or just the "autopilot", controls the aircraft's flight controls to automate maneuvering. It is interfaced on the UFC via the A/P button.

The most basic mode of the AFCS is Control Stick Steering (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. The trim switch is repurposed in CSS to command roll and pitch. 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.

Source:
https://wiki.hoggitworld.com/view/F/A-18C#AFCS

[Stearmandriver]

Sounds like how the ATTH mode has worked the whole time I've been using the DCS Hornet??

[Tholozor]

ATTH hold is not the same as engaging basic A/P mode. Think of it as a "pilot relief" mode that doesn't focus as aggressively holding a specified parameter like ATTH, BALT, or RALT do.

Edited May 21, 2021 by Tholozor

[Steel Jaw]

Is there a link for the latest version of the Hornet manual?

[Bunny Clark]

1 hour ago, Stearmandriver said:

Sounds like how the ATTH mode has worked the whole time I've been using the DCS Hornet??

Yah, CSS has been in the Hornet for a long time. Years. 

 

CSS is available in pitch and roll in ATTH, and in roll only in BALT and RALT.

[Furiz]

ATTH wasn't working correctly before, you couldn't pitch the aircraft you could only roll, now it works fine.

[Pieterras]

@Bunny ClarkYou are absolutely correct.. I just tried it myself and it does not work the way it should... I am not even going to bother with providing prove of how it should, as NATOPS states quite clearly how it should... 

In CCS mode you should be able to fly the aircraft through dampened control inputs, or by the use of the trim switch... At the moment it works correctly for roll, however if you control the pitch with the trim switch, it does not return to normal logic when CCS mode of the A/P is disengaged. 

[=4c=Nikola]

I don't even understand why would a fbw aircraft need CS mode. Maybe it makes sense to have it as a reversion mode.

Edited May 21, 2021 by =4c=Nikola

[Bunny Clark]

6 hours ago, =4c=Nikola said:

I don't even understand why would a fbw aircraft need CS mode. Maybe it makes sense to have it as a reversion mode.

 

It's used for making fine adjustments to a held attitude when autopilot is engaged. For example you could set the aircraft to hold a climb and adjust the pitch with the stick or trim hat, or use the stick or trim hat to adjust your bank angle in an altitude held orbit. It's not a way to "fly" the aircraft, the plane doesn't respond quite that way, it's a way to change autopilot values with the stick or trim. 

 

Most people have probably used CSS already without even knowing it. If you've ever used the stick to make roll inputs while in BALT you've used CSS. You can use the trim hat to do the same thing, but at a fixed roll rate.

Edited May 21, 2021 by Bunny Clark

[=4c=Nikola]

6 minutes ago, Bunny Clark said:

It's used for making fine adjustments to a held attitude when autopilot is engaged. For example you could set the aircraft to hold a climb and adjust the pitch with the stick or trim hat, or use the stick or trim hat to adjust your bank angle in an altitude held orbit. 

 

Most people have probably used CSS already without even knowing it. If you've ever used the stick to make roll inputs while in BALT you've used CSS. You can use the trim hat to do the same thing, but at a fixed roll rate.

 

So it is basically just a mode reversion.

[Santi871]

CSS just means the aircraft's autopilot and/or FBW will adjust the flight surfaces to maintain the last pitch/roll reference when the stick/yoke was centered.

 

You can have CSS (or similar) without FBW (737 CWS), you can have FBW but no CSS, FBW with manually enabled/disabled CSS (Hornet), or FBW that sort of behaves as if CSS is on (A320 in certain parts of the flight).

 

Like someone else said, you can turn on CSS directly in the Hornet by pressing A/P then ON, and it will also fall back to CSS if another A/P mode is disabled/decolonized. In either case you'll get an A/P advisory. The only way to kick off A/P entirely without it falling back to CSS is to use the paddle.

Edited May 22, 2021 by Santi871

[Storm_ctrl]

Was this CSS bug with the trim ever resolved?