2 hours ago, ha5mvo said:

The real bus will not change altitude in cruise if you change the pressure. I suppose they modeled it correctly 

Well, that doesn't work... When I switch from STD to QNH before TOD the alt changes on the PFD...

45 minutes ago, tup61 said:

Well, that doesn't work... When I switch from STD to QNH before TOD the alt changes on the PFD...

It does, but the real thing should maintain it’s altitude. If that’s not the case and the plane attempts to capture a new one, then fenix got it wrong.

From memory I believe it indeed does not climb or descend. When you change to qnh, the autopilot maintains level fligh.

Edited June 12, 20223 yr by ha5mvo

1 hour ago, ha5mvo said:

It does, but the real thing should maintain it’s altitude. If that’s not the case and the plane attempts to capture a new one, then fenix got it wrong.

From memory I believe it indeed does not climb or descend. When you change to qnh, the autopilot maintains level fligh.

I will give this another try. I saw the alt tape changing and didn't really check if the plane actually started as/descending but quickly went back to Std to avoid problems... 😉

Edited June 12, 20223 yr by tup61

1 hour ago, ha5mvo said:

It does, but the real thing should maintain it’s altitude. If that’s not the case and the plane attempts to capture a new one, then fenix got it wrong.

From memory I believe it indeed does not climb or descend. When you change to qnh, the autopilot maintains level fligh.

I have adjusted the QNH while cruising level and never saw the aircraft either climb or descend. The altimeter changes, but the aircraft remains in level flight. 

Edited June 12, 20223 yr by Bobsk8

25 minutes ago, Bobsk8 said:

I have adjusted the QNH while cruising level and never saw the aircraft either climb or descend. The altimeter changes, but the aircraft remains in level flight. 

Good to know! 

I'd still like to know the best way to pre-set QNH while descending... 

2 minutes ago, tup61 said:

Good to know! 

I'd still like to know the best way to pre-set QNH while descending... 

Well you need to get the setting from someplace, either ATIS at the arrival airport, or on the Fenix you can look at the flight plan page in the EFB and it will show you Metar for the arrival , or you can find that in MSFS, on the Metar page. If all else fails, hit the B key . 

The real Airbus AP remembers current pressure altitude when ALT mode is engaged. That means after ALT has engaged you can change the baro setting without direct impact on flight guidance.

That means also when you reach a certain altitude with baro != STD and ALT mode engages setting it then to STD will not make the aircraft correct the error.

If you need to correct it you obviously need to use a vertical mode and ALT needs to arm. This does only happen when you either dial back and forth the FCU altitude or the error is larger than 250 ft. Otherwise you either will not be able to engage the vertical mode (i.e. OP CLB/DES) or in case of V/S ALT is not armed and therefore it will not capture the target altitude.

This has been verified in a FFS by the way.

Edited June 12, 20223 yr by AGuther

3 minutes ago, Bobsk8 said:

Well you need to get the setting from someplace, either ATIS at the arrival airport, or on the Fenix you can look at the flight plan page in the EFB and it will show you Metar for the arrival , or you can find that in MSFS, on the Metar page. If all else fails, hit the B key . 

LOL I seem to have a problem today with making myself understood. I have no problem at all finding QNH. The problem is that when I switch from STD to QNH during descend and the set number is way off I have to change the number and the Airbus reacts to that. So... I'd like to set the proper QNH before I switch to it. That is my question. I read a short how to do it post a while ago but can't find it anymore. It involved changing modes during descent. This would prevent the plane from reacting while changing the number. 

2 minutes ago, tup61 said:

LOL I seem to have a problem today with making myself understood. I have no problem at all finding QNH. The problem is that when I switch from STD to QNH during descend and the set number is way off I have to change the number and the Airbus reacts to that. So... I'd like to set the proper QNH before I switch to it. That is my question. I read a short how to do it post a while ago but can't find it anymore. It involved changing modes during descent. This would prevent the plane from reacting while changing the number. 

The airbus does not react to you changing the altimeter setting as was explained to you a couple of times. If yours is reacting there is something wrong with your setup....I just tried moving the altimeter when cruising 10 minutes ago, and the only thing that changes is the altimeter reading. The aircraft remains in level flight. 

40 minutes ago, Bobsk8 said:

The airbus does not react to you changing the altimeter setting as was explained to you a couple of times. If yours is reacting there is something wrong with your setup....I just tried moving the altimeter when cruising 10 minutes ago, and the only thing that changes is the altimeter reading. The aircraft remains in level flight. 

I know I know I know! 😉 I see a reaction only when I change QNH while descending. And I want to prevent that by pre-setting the correct QNH before I have to switch to it. 

Just now, tup61 said:

I know I know I know! 😉 I see a reaction only when I change QNH while descending. And I want to prevent that by pre-setting the correct QNH before I have to switch to it. 

What reaction exactly do you see?

16 minutes ago, tup61 said:

 … And I want to prevent that by pre-setting the correct QNH before I have to switch to it. 

Then why don’t you set it while approaching your TOD - as described a couple of times above?

1 hour ago, Bobsk8 said:

What reaction exactly do you see?

Pitching up or down depending on the QNH. Not a huge problem but not comfortable for the pax. When QNH is a lower number, VS and SPD become lower and when QNH is a higher number, VS and SPD go up (as shown in all cases by the trend on the tapes). I'd like to prevent that.

 

  

49 minutes ago, SierraDelta said:

Then why don’t you set it while approaching your TOD - as described a couple of times above?

Because as I also already said I don't want to pre-set QNH too soon. Although that would of course usually prevent large changes.

Edited June 12, 20223 yr by tup61

2 minutes ago, tup61 said:

Pitching up or down depending on the QNH. Not a huge problem but not comfortable for the pax. When QNH is a lower number, VS and SPD become lower and when QNH is a higher number, VS and SPD go up (as shown in all cases by the trend on the tapes). I'd like to prevent that.

 

  

 

I have never seen that in about 30 flights. Are you flying the Fenix? 

I find this post as a strange topic. I am US based and wonder why would a person want to preset an altimeter setting. I do get that in other countries, you may be closer to the ground and destination when this change over happens. I fly internationally, but will set the altimeter when passing transition. In all of the jets I've flown real world, changing the setting will adjust the ref that the autopilot is using. It is normally minimal and unnoticeable unless you are looking at the altimeter as you set it. The displayed altitude may rise or fall a little and the plane will slightly pitch accordingly. In the DC10, the pilot flying would set the given altimeter when cleared below, but the PNF and the STBY altimeter kept STD until passing below it. Occasionally, You will get cleared below and then held before transition. In that case, you have to remember to change back to STD. In my gulfstream ops, we set the setting in the STBY when given and cleared below. Passing, we set it all around.