Autopilot/altimeter bug KA 350i [resolved - SP patch]

[c.lerche]

Hello
Thank you for a nice aircraft! Be aware of a small bug that causes the autopilot to disconnect/unable to engage when changing the baro units from inHg to hPa. When changing back to inHg the autopilot seems to behave normally.

/Christian Lerche

[Taguilo]

Hi,

It is not happening to me. Are you talking of changing units in the KA, through Refs menu page 2? or in P3D menu?


Tomas

[paul.ziegler96]

it happened to me today too. Was flying with hPa Altimeter through Refs menu page 2 and could not engage AP up to 5min into flight and at one point it just was possible, couldn't figure out why...

[iangrant1981]

Did you get the amber 'ALT' indication at the top of the altimeter tape on the PFD? I get it sometimes when changing the baro and when that is present, the AP cannot be engaged. Seems clearable by resetting STD... not sure what the cause is.

[Taguilo]

Ok, I see what might have happened.

Each one of the three altimeters is set individually. If you want to set them manually, you must do it to all. Otherwise, if there is a difference in baro alt between pilot and copilot units, and that difference is big enough to display an amber line below the altimeter reading, autopilot will detect the mistmatch and auto disengage. It won't engage again until baro readings are normalized.

Pressing B key will normalize pilot, copilot and ESIS altimeters to the current value.

Pressing Baro knob also normalized the three altimeters to STD value.

Tomas

[paul.ziegler96]

Ok didn't know left and right Baro are individual! Thanks for the clarification.

[hasse.w]

would request an option in Milviz controlpanel , sync CP and FO baro like in all hi end Addons. ( they already synced the STD setting)
if you fly online get qnh 1001 you cant fiddle with 2 baros or hope that B actual conditions ar the same as at the airport.

[Taguilo]

Hi,

Actually the individual altimeter setting is an intended feature. Part of training is to set & check proper altimeter values on both PFD, as otherwise will produce malfunctions in autopilot and other systems.

For those who prefer a shortcut, (B) keypress option works fine.

Anyway, a future checkbox in MVAMS might be considered as well.

Tomas

[hasse.w]

Actually the individual altimeter setting is an intended feature. Part of training is to set & check proper altimeter values on both PFD, as otherwise will produce malfunctions in autopilot and other systems.

Yes thats true the pilots normally turn their baros, PF say ONQ xxxx set PM respond QNH xxxx Cross Checked PM passing xxxxxFeet Now PF respond Checked, with Sync CP and FO you can check the setting , in my option more realistic then turn booth baros if you train yourself without any FO
but but you train as you have one.

Thanks for a very nice Bird

[matpietsch]

Hi,

Actually the individual altimeter setting is an intended feature. Part of training is to set & check proper altimeter values on both PFD, as otherwise will produce malfunctions in autopilot and other systems.

For those who prefer a shortcut, (B) keypress option works fine.

Anyway, a future checkbox in MVAMS might be considered as well.

Tomas

Actually in real world single pilots ops: is the pilot supposed to reach over to the other(Copilot) display?

[Taguilo]

[
Actually in real world single pilots ops: is the pilot supposed to reach over to the other(Copilot) display?

Yes, copilot one is not that far away, easy to reach.

Tomas

[markus.buensen]

Hi Tomas,

just a quick input here. The real aircraft autopilot does not auto-disengage from a split baro setting.

Best regards,

Markus

[Taguilo]

Hi Markus,

AP does not disengage because of baro split, but when it detects an inconsistency between both FGC computers data.

For example, if altitude displayed on each ADI differs beyond a limit (due to different baro settings) AP will disengage, and a single ADC must be selected as a source for both FGC before the AP can be reengaged.

Regards,

Tomas

[markus.buensen]

Hi Tomas,

well, I am pretty sure that that is not the case. The QRH lists among other issues FGC failures to trigger an AP auto-disengagement, which makes sense as it means the FGC does not work anymore and does no longer produce valid steering data for the AP.
However, I will not make a final statement before I have tried it in the aircraft. What threshold do you think would disengage the AP? I flew today with a split of 10 hPa and it didn't disengage the AP. Also, miscompare flag like HDG or ALT do not disengage the AP.
But again, I will try to force the aircraft to do it, however I won't be on the PL21 again before later this month.

Best regards,

Markus

[markus.buensen]

Hi everyone!

Hope you are all doing well in the current situation!

I just wanted to say that I tested the baro setting split on our RW PL21 King Air 350 and I can confirm that the autopilot does NOT disengage from a baro split regardless how long you leave the setting split. As long as all data is valid, the AP will just stay in and follow the signals of the selected FGC (as selected by the CPL button on the FGP).

Best regards and stay safe at home!!

Markus