[CHECKING] There might be a bug with the RALT and BALT autopilot modes

[imacken]

Probably from NATOPS or another publicly available document for the Hornet I would guess.

 

The break down of the 5 autopilot functions for the F/A-18C Hornet are as follows:

 

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. 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.

 

Attitude Hold (ATTH):

Maintains the current pitch attitude plus or minus 45° and the current bank angle plus or minus 70°.

 

Heading Select (HSEL):

Seers to the current heading selected by the heading select switch. The current heading can be viewed on the Horizontal Situation Indicator format.

 

Barometric Altitude Hold (BALT):

Maintains the current barometric altitude between 0 and 70,000ft.

 

Radar Altitude Hold (RALT):

Maintains the current radar altitude between 0 and 5,000ft.

 

 

Coupled Steering (CPL):

Maybe this is what you are experiencing when pressing the A/P ON/OFF button?

The CPL (coupled steering) option (if available) in the UFC

option display windows. When a pilot relief option is selected via the UFC a colon (:) appears in front

of the selected display and the selected mode appears on the DDI advisory display. If an option is not

available, it is not displayed. When the CPL option is selected on the UFC, the flight controls will

couple to that steering mode (in azimuth only).

 

^^ simply highlighting as there is really no direct documentation regarding the sole depression of the on/off button on the UFC when in the A/P mode ^^

 

 

A/P being displayed on the DDI simply means an autopilot mode is selected.

 

 

 

Cheers,

 

Don

 

Thanks for that Don.

 

The mode being mentioned as the 'heading hold' mode looks like the CSS not CPL.

 

Still, I am very confused here. I don't know where BarTzi gets the 'heading hold' thing from, as it certainly doesn't hold heading!

 

Also, the CPL mode is not a UFC option in DCS. (Could be coming later, I guess.)

 

I can't see the difference between CSS and ATTH.

 

A/P being displayed on the DDI is shown whenever the ON/OFF is selected and this mysterious mode is apparently implemented without selecting any mode on the UFC.

 

I'm beginning to wonder if there is some kind of bug here.

[BarTzi]

Still, I am very confused here. I don't know where BarTzi gets the 'heading hold' thing from, as it certainly doesn't hold heading!

.

 

NATOPS.

 

"2.9.2.1 Autopilot.

 

The basic autopilot (heading hold) is engaged by selecting the A/P pushbutton (at

which time pilot relief options appear on the UFC) then selecting the ON/OFF pushbutton.

Engagement is indicated by the A/P advisory on the DDI. Selecting the ON/OFF pushbutton is not

required if ATTH, HSEL, BALT, RALT, or CPL (MC OFP 13C AND UP) option on the UFC is

desired.

 

At this time the aircraft maintains the existing pitch attitude. If roll attitude is less than or equal to

±5° at engagement, the magnetic heading is maintained. If roll attitude at time of engagement is

greater than ±5°, the roll attitude is maintained. The pitch attitude hold reference can be changed with

pitch CSS to any value between ±45° pitch. The pitch attitude reference can also be changed with the

trim switch on the control stick at a rate of 0.5°/second. The roll attitude hold reference (if roll is

greater than ±5°) can be changed with roll CSS to any value between 5° and 70° of roll. The roll

attitude reference can also be changed using the trim switch on the stick at a rate of 2°/ second. The

magnetic heading reference (if roll is less than or equal to ±5°) can be changed, or initially set with roll

CSS. The roll trim switch also can change the reference magnetic heading."

 

Also from NATOPS:

 

"The automatic flight control system (autopilot) has two basic modes: pilot relief and data link. The

pilot relief mode consists of heading hold, heading select, attitude hold, barometric altitude hold, radar

altitude hold, control stick steering (CSS) and coupled steering. The data link mode consists of

automatic carrier landing (ACL), precision course direction, and vector approach."

 

@imacken @daarseth, please read this comment and the previous one. Clearly shows when it holds heading and when it holds the roll.

 

A/P advisory should not be on when you select an autopilot mode using the UFC. It should only be displayed under certain conditions. Let's shift the focus back to the bug report.

Edited November 12, 2019 by BarTzi

[imacken]

OK, thanks for clearing that up. Looks like a couple of modes are missing from the DCS Hornet at this stage of development, and I can see how 'heading hold' works now. Strange how that mode works as per the NATOPS manual, yet it is not mentioned in either the ED EA Guide or Chuck's Guide.

 

Re your 'bug', I am not able to replicate the behaviour in your track of BALT, but I'll give it another try!

[Arctander]

So a year and a half after release the autopilot modes aren’t working/implemented properly...

 

I’m sure Balt was a lot more reliable a few months ago...

[Ziptie]

Shift away BarTzi.

 

 

Cheers,

 

Don