MSFS 1.15.8.0 wrong climb to altitude with Live weather

[ryanbatc 12,806]

This has been happening since alpha.

Plane will climb to whatever it thinks is the pressure altitude not what is set on the AP ALT SEL.  This is incorrect.  IRL plane will climb to selcted altitude and if the pilot entered altimeter incorrectly it would show on air traffic radar.

Asobo might have done this as a clue that a user's altimeter setting is wrong.  But it's still weird.

[vonmar 122]

18 minutes ago, ryanbatcund said:

This has been happening since alpha.

Plane will climb to whatever it thinks is the pressure altitude not what is set on the AP ALT SEL.  This is incorrect.  IRL plane will climb to selcted altitude and if the pilot entered altimeter incorrectly it would show on air traffic radar.

Asobo might have done this as a clue that a user's altimeter setting is wrong.  But it's still weird.

Ryan,

Thanks for confirming.

I had no Idea it was a long standing problem.

I just did another test but with P3Dv4.5HF3 and Active Sky

KSEA ATIS reporting Baro 30.17

Rwy 16L dialed 29.92 altimeter 180 Feet (for a non standard day, naturally) .

Same test per my first post MSFS is 230 feet. As far as I can see that is the problem area.

 

 

 

 

[crimplene 631]

1 hour ago, ryanbatcund said:

This has been happening since alpha.

Plane will climb to whatever it thinks is the pressure altitude not what is set on the AP ALT SEL.  This is incorrect.  IRL plane will climb to selcted altitude and if the pilot entered altimeter incorrectly it would show on air traffic radar.

Asobo might have done this as a clue that a user's altimeter setting is wrong.  But it's still weird.

Strange, never had that. But I only use the APs in the FBW A320 and the CRJ. They react to selected pressure as expected.

[ryanbatc 12,806]

26 minutes ago, crimplene said:

Strange, never had that. But I only use the APs in the FBW A320 and the CRJ. They react to selected pressure as expected.

Right they're custom coded.  I've seen this issue all of the default aircraft (incl premium).

[sd_flyer 6,032]

Explanation is very simple! Default autopilot altimeter read different barometric pressure from what we set  in Kollsman window (via Live Weather feed). Since we can't adjust autopilot barometric setting we get altitude discrepancy. This known problem the beginning of time.

 

FYI if we set 29.92, we get "pressure"" altitude which used in a of manual as part of performance calculation . Of course if weather conditions very close to standard then pressure altitude= airport elevation MSL

 

[vonmar 122]

I do not have CRJ to test.

I did another test:
MSFS CJ4
MSFS Live weather
KSEA 16L
ATIS altimeter 30.17 runway altitude 425 feet
Baro 29.92 runway altitude 175 feet (for this test)
250 feet difference (for this test)
Departure Altimeter set to 30.17
Autopilot , climb to 5000 feet at 590 feet / min

All ok, CJ4 stopped at 5000 feet

 

[marsman2020 1,310]

People keep going on an on about this but I've never seen it after flying over 9000 miles around the world in the Bonanza.

The OP has been very demanding and rude in this thread in my opinion but I'm going to try this now just so I don't go nuts.

Removed all Community folders mods. 

Sitting on the ground at KSEA Runway 16L.  Hit 'B'.  Baro is set to 30.17 IN. 

G1000 reads between 420 and 430. 

LittleNavMap says 'Indicated Altitude' is 425ft and 'Actual Altitude' is 425ft.  They match perfectly.

(If I play with the Baro setting in the G1000, the 'Indicated' altitude in LNM changes to match what the G1000 says)

Set desired altitude to 3000 ft.  Dial in a 1000ft/min climb.  Takeoff and enable AP.

AP levels off at exactly 3000 ft indicated altitude on the G1000.

LittleNavMap says 'Indicated Altitude' is 3000ft and the 'Actual Altitude' is 2975 ft, the AP stopped correctly based on the indicated altitude shown on the G1000, not based on any other magical altitude reading.

I see no problems.  The G1000 altitude display changes correctly based on the Baro setting and the AP stops based on what the G1000 is showing.

Edited April 18, 2021 by marsman2020

[marsman2020 1,310]

Tried a G1000 based aircraft, let's try a G3X based aircraft, at another airport.

On the ground at MMAS in an XCub.  Hit 'B'.  Baro set to 30.15.  LNM says Indicated = 6099 ft, Actual = 6098 Feet

Set AP altitude to 10000 feet.  Takeoff and engage AP.

AP levels off at 10000 feet as indicated on the G3X.  LNM says Indicated = 10000ft, Actual = 10000 ft.  AP stopped correctly based on what is shown on the G3X.

Edited April 18, 2021 by marsman2020

[vonmar 122]

I just did another test with MSFS Live weather.

MSFS version is 1.15.8.0

Baron KSEA

ATC altimeter is 30.17

If I select a departure with the Baro set to 29.92 (rwy alt 175 feet) it climbs 800 feet/minute to the armed/select altitude , in this case 3000 feet. All ok.

I have screenshots if needed.

 

 

Edited April 18, 2021 by vonmar

[marsman2020 1,310]

G3000/5000 based aircraft.

On the ground at KRNT in TBM930.  Hit 'B.'  Baro set to 30.16.  LNM says indicated = actual = 32 feet.

Set AP altitude to 8000 ft.

AP levels off at 8000 ft as indicated on the G3000. LNM says Indicated = 8000 and Actual = 8010.

Again, I see no issues.

[vonmar 122]

Can you test the Baron like I reported in my first post?

[marsman2020 1,310]

 

17 minutes ago, vonmar said:

Can you test the Baron like I reported in my first post?

Removed - will repost in a second

Edited April 18, 2021 by marsman2020

[vonmar 122]

1 minute ago, marsman2020 said:

 

The Baron seems to be broken and does not behave the same as the other 3 aircraft.

On the ground at KMHV in the Baron.  Set the altimeter baro to 32.01 which is as high as it goes.  Altimeter reads 4635 ft.  LittleNavMap says Indicated = 4635 ft and Actual = 2795 ft (a delta of 1840ft).

Set AP altitude to 10,000ft.  Takeoff and engage AP.

AP levels of when the indicated altitude = 12080 ft.  LittleNavMap says Indicated = 12081 and Actual = 10214.

I'd file a ZenDeck ticket but you'll need a really clear explanation to get anyone to do anything. 

Also, I'm out, I'm not testing all 30 aircraft to see which APs are broken or not 😉

Thanks for help testing and confirming the MSFS problem.

Initially I thought a forum member could try the exact same test I did in my first post to confirm the numbers.

It is just a ten minute test.

The Baron is not the only aircraft with the problem as I previously reported during testing in this topic.

Thanks again.

 

 

 

 

 

[marsman2020 1,310]

Well, I took that post down so I could double check.

Tried it again with a less extreme example, Baron at KSEA.

Set the altimeter baro to 30.16.  Altimeter reads 425 ft.  LittleNavMap says Indicated = 425 ft and Actual = 425 ft.

Set AP altitude to 5000ft.  Takeoff and engage AP.

AP levels of when the indicated altitude = ~5000 ft.  LittleNavMap says Indicated = 4995 and Actual = 4986 (the atmospheric pressure is changing in this area which caused the 10ft error).

So it seems like with a more 'typical' example everything works fine.

Increase altitude setpoint to 8000ft and used 'B' key to again set the baro pressure (now 30.15).  Engage climb

AP levels off when the indicated altitude = 8000ft.  No problem.

Increase altitude setpoint to 12000ft. Engage climb

AP levels off when the indicated altitude = 12000ft.  No problem.

The only way I was able to get anything to misbehave was by using settings way off of reality.

[fppilot 4,351]

7 hours ago, ryanbatcund said:

This has been happening since alpha.

Plane will climb to whatever it thinks is the pressure altitude not what is set on the AP ALT SEL.  This is incorrect.  IRL plane will climb to selcted altitude and if the pilot entered altimeter incorrectly it would show on air traffic radar.

Asobo might have done this as a clue that a user's altimeter setting is wrong.  But it's still weird.

Asobo likely established it as if all flight were at altitudes above 18,000 ft.  Innocent about flying, rooted only in gaming!
Read it in a book somewhere!

 

Edited April 18, 2021 by fppilot