Autopilot trouble

[Devil 505]

3 hours ago, BIGNEWY said:

Hi, thank you for the video, but if possible we need a track replay, when you exit the mission you can save the track during the debrief screen. 

if possible use the air start instant action free flight mission and try to reproduce. 

we will then be able to see what is happening and check the controls indication and take control of the track if necessary 

thank you

Will do Bignewy.  I will knock out the video as requested after work.  

[Hawkeye91]

1 hour ago, Devil 505 said:

Will do Bignewy.  I will knock out the video as requested after work.  

Just for clarity he needs the TRACK FILE  that DCS generates after you finish a mission, not a video. 

[Devil 505]

3 hours ago, Hawkeye91 said:

Just for clarity he needs the TRACK FILE  that DCS generates after you finish a mission, not a video. 

Rog, I am trackin.  Just need to save a track when I am done.  I never save them.

[Devil 505]

16 hours ago, BIGNEWY said:

Hi, thank you for the video, but if possible we need a track replay, when you exit the mission you can save the track during the debrief screen. 

if possible use the air start instant action free flight mission and try to reproduce. 

we will then be able to see what is happening and check the controls indication and take control of the track if necessary 

thank you

As requested, track file attached.  With hands off and directly on the horizon line on the HUD, the BALT AP would engage, but it still gave me issues being the slightest bit off the artificial horizon line.  A lot of master cautions.  I am ok if it is user error, but it seems off to me.  This was the F-18 free flight instant mission on the Caucus map.  Really appreciate the help Bigs.  Seems like I am not the only one with this issue.

SHL 2.trk

[Razor18]

Would you please check in Controls selecting "Axis commands", when yo do not touch your joystick, is any white "input" line left or right of the field center visible on either X (Roll) or Y (Pitch) axis? If your joystick is really centered in neutral, there should be no white line at all in the middle on the axis  line. If there is even the smallest white line, this would mean your joystick is not neutral, even when you do not grab it. Which causes exactly what you say, Master caution and I guess "Autopilot off" or something similar note when you try to engage Autopilot, because in game the aircraft senses a small input, and refuses to engage autopilot.

Apologies if you already knew it...

[Devil 505]

10 minutes ago, Razor18 said:

Would you please check in Controls selecting "Axis commands", when yo do not touch your joystick, is any white "input" line left or right of the field center visible on either X (Roll) or Y (Pitch) axis? If your joystick is really centered in neutral, there should be no white line at all in the middle on the axis  line. If there is even the smallest white line, this would mean your joystick is not neutral, even when you do not grab it. Which causes exactly what you say, Master caution and I guess "Autopilot off" or something similar note when you try to engage Autopilot, because in game the aircraft senses a small input, and refuses to engage autopilot.

Apologies if you already knew it...

No apologies needed.  This may be the case as to why I am having issues.  I just remember before, it was not this sensitive.  If this is the case with the real aircraft, then I would want nothing changed.  I just saw people complaining about needing to adjust the sensitivity on the axis controls when it should not need to be adjusted.  This is turn was making AAR harder.  I can manage with the way it is, just have to be more aware of the stick moving.

[Razor18]

Just curious, did you check it?

[dingoniner]

I have my joystick deadzones at 100%.  I'm at 10,000 feet, vertical velocity is zero.  And my BALT won't function, gives me a master caution.

HOWEVER....if I go directly into free flight, the autopilot functions wonderfully.  The times that it doesn't work are when I go through the engine start process.

Anyone know what I might be missing during the startup?  I see INS degradation as a caution, but would that cause a simple BALT to not function?

Edited May 16, 2023 by dingoniner

[Tholozor]

1 hour ago, dingoniner said:

I see INS degradation as a caution, but would that cause a simple BALT to not function?

Yes. If the INS isn't aligned, it has no reference to send to the control surfaces to maintain altitude since it doesnt know your attitude.

[SharpeXB]

On 1/30/2023 at 1:17 AM, BIGNEWY said:

Hi, thank you for the video, but if possible we need a track replay, when you exit the mission you can save the track during the debrief screen. 

if possible use the air start instant action free flight mission and try to reproduce. 

we will then be able to see what is happening and check the controls indication and take control of the track if necessary 

thank you

Track file here. But this isn’t a controller bug so it shouldn’t have been moved to this category  

 

[dingoniner]

On 5/15/2023 at 9:17 PM, Tholozor said:

Yes. If the INS isn't aligned, it has no reference to send to the control surfaces to maintain altitude since it doesnt know your attitude.

I would think that the autopilot altitude lock doesn't need to know your altitude.  It's not going to maintain any particular altitude, it's just going to prevent it from changing.  It's not hard to measure a change in altitude (a change in pressure).  When the pressure drops, your altitude has gone up.

But I'll try a full startup again and make sure I have no INS degradation, and see if this makes a difference.  Thanks.

Update:  Even with no INS degradation, I still get a Master Caution and neither barometric nor radar altitude hold will engage.  But it does work if I start a flight in the air.  I must be doing (or not doing) something during the startup that is causing this.  Any insights?

 

 

What am I missing in the startup?

Edited May 22, 2023 by dingoniner

[unlikely_spider]

On 5/15/2023 at 9:17 PM, Tholozor said:

Yes. If the INS isn't aligned, it has no reference to send to the control surfaces to maintain altitude since it doesnt know your attitude.

Is barometric altitude really determined by the INS and not by the pitot tube?

[dingoniner]

5 hours ago, unlikely_spider said:

Is barometric altitude really determined by the INS and not by the pitot tube?

Barometric altitude is determined by the static port, and is calibrated with an altimeter setting.

Edited May 23, 2023 by dingoniner

[Tholozor]

2 hours ago, unlikely_spider said:

Is barometric altitude really determined by the INS and not by the pitot tube?

Your point is valid, but my point is that the aircraft needs to know how it's oriented in space in order to send the correct commands to the flight controls to maintain the captured altitude.

If the gyros aren't aligned, for all the system knows the aircraft is flying knife-edge sideways, or upside-down, or some other orientation that's outside the limits of engaging BALT.

Edited May 22, 2023 by Tholozor

[unlikely_spider]

21 minutes ago, Tholozor said:

Your point is valid, but my point is that the aircraft needs to know how it's oriented in space in order to send the correct commands to the flight controls to maintain the captured altitude.

If the gyros aren't aligned, for all the system knows the aircraft is flying knife-edge sideways, or upside-down, or some other orientation that's outside the limits of engaging BALT.

 

I understand, thank you.

I've flown real planes that have an altitude hold function that don't have any INS at all, but I'm sure the safeguards are not as fully-featured as jet fighters, and also I don't pretend to know the mechanics of how the autopilot works.

Edited May 22, 2023 by unlikely_spider

[dingoniner]

3 hours ago, unlikely_spider said:

I understand, thank you.

I've flown real planes that have an altitude hold function that don't have any INS at all, but I'm sure the safeguards are not as fully-featured as jet fighters, and also I don't pretend to know the mechanics of how the autopilot works.

 

So yeah, INS definitely plays a role.  In free flight, starting straight and level, autopilot works fine.  Turn the INS off, and autopilot doesn't work at all.  Turn it back on, it still doesn't work (not calibrated?).  Master Caution said "AUTOPILOT" and "INS DEGRD"

So the issue is..what am I doing wrong on startup with the INS?  I'm pretty sure it's calibrated properly, and I have no INS DEGRD when I'm flying.  More research is in order...

[Tholozor]

1 hour ago, dingoniner said:

So the issue is..what am I doing wrong on startup with the INS?  I'm pretty sure it's calibrated properly, and I have no INS DEGRD when I'm flying.  More research is in order...

A track file of your startup and/or the issue would help diagnose this.