World's Challenging Approaches -6 |LXGB|3-3-2018|16:00Z |

[Octal450]

@SHM
I can tell you aswell, that the autopilot goes through extreme testing, the control loop is tested in severe weather conditions far worse than what we were flying through. All through doing this, the aircraft is subjected to interruptions throwing the system off and it must remain stable, and it has passed all these tests. Therefore, I find it highly unlikely that the aircraft was at fault, especially considering no other incidents of this have ever occurred with this, or any of the IT-AUTOFLIGHT based autopilots.

I blame the poor weather system in FlightGear. I believe what happened is the AP was tripped off due to the weather update causing a temporary overspeed condion (even if only for a split second). This introduces a pitch up command from the FBW, which likely means the aircraft became stalled after climbing too high. At that altitude, even a small pitch up will cause it to go upwards toward the service ceiling. Keep in mind the only stall protection I have simulated so far is the ALPHA FLOOR function of the autothrottles.

The aircraft was not the root cause here, I am 100% sure of that, especially since I saw it fly through the service ceiling (on MPmap, then twist and fall to the ground), something that WILL cause a stall due to lack of engine power to compensate at that altitude.

My point is... please don't insult the aircraft without knowing what went wrong. The most likely scenario is the weather thing, which has happened once before, but this is not a fault with the aircraft, but with the weather system.

Kind Regards,
Josh

[SHM]

I was not insulting your aircraft, I was just talking about the fg experience as a whole.

[V12]

FG weather change ruined some my flights too.
But there is one more theory :
SM, didn't You disabled AP by accidental hit of joystick and did not observed that event ?
I departed from LOWI via SID RTT2Q, engaged AP. George worked perfectly. Then wife needed my help in the kitchen. And when I went to help her, hit the joystick on the desk. And when I returned back, found poor Bus crashed. On the saved tape was clearly visible that moment, when AP was disconnected by my joystick hit.

[SHM]

FG weather change ruined some my flights too.
But there is one more theory :
SM, didn't You disabled AP by accidental hit of joystick and did not observed that event ?

No that was not the case, probably its the METAR bug like Josh said because the joystick was not connected at the moment.

I checked fgtracker.ml but the log was not there. (Looks like I didnt connect to one of the tracked servers )

[Octal450]

Rgr.

I did notice the metar was jumping around frequently during this flight... They really need to sort that.

Maybe I can figure out a way to detect such spikes and ignore them... Hmm.

Kind Regards,
Josh

[V12]

There are no spikes, only steep baro pressure changes, when new METAR is loaded. Secondary effect is very ugly - You are flying in nice weather with clear sky, in the next second You are surrounded with cumuluses. This is second reason, why I'm flying with Concorde - far over the weather. Only change of the baro altitude is annoing. That changes sometime disconnect AP.

[V12]

SHM :
Thank You for perfect event, in my case ruined by DOG's two times runway incursions, when I was on short final. Result :



But third attempt to land was successful, I landed smoothly and safe.

[SHM]

Good job on landing after the issues

[Octal450]

@V12
The Airspeed indicator spikes up/down for a split second. It can't be seen easily, but a graph of the property in Phi showes it.
The Baro altitude sometimes does it also, but I've overcome that in my IT-AUTOFLIGHT, and those autopilots can deal with it smoothly, without a problem. However, the overspeed logic in the Airbus happens to be executed in the timer exactly when the spike occurs, it will trip the Autopilot.,

Kind Regards,
Josh

[V12]

Did Your logic shut down AP in case of extreme vertical speed ?