This evening I performed a flight between LPPT and EHAM with the A319.
Flight Plan: IXIDA2S IXIDA DCT TOSDI UN745 ZMR UN873 FERDI UY18 DENUT DENUT1A
Takeoff ZFW: 57.285 kg
Takeoff Fuel: 9053 kg
The issue occurred during the descent above DENUT and RIVER
Operating System: Windows 10 64 bit Professional Simulator version: Prepar3d v4.4 Airbus version: 126.96.36.199
Aircraft: A319 CFM (TAP livery) Add-ons in use:
- ActiveSky for P3DV4
- ORBX (global, vector, LC europe)
- Navigraph Airac (1902)
- Various Airports: FlyTampa, MK studios
INTEL i7-4790K CPU @ 4.00GHz - 24GB RAM
Description of the issue:
During the climb and cruise portion of the flight, nothing special happened. At about 100NM prior to descent, I entered all the destination data (wind, QNH, temp, DH). 40NM prior to descent I updated the wind info. About 5NM prior to the TOD I altered the altitude on the FCU to FL240 (first constraint of the STAR; cross DENUT at or below FL240) and pressed the knob. As expected at that moment, I was descending below the vertical profile with a VS of -1000 ft/m. However, after 5min I was still below the profile. All of a sudden the profile dropped completely. In a matter of seconds, I was not below, but above the profile. The autopilot corrected this with a steep dive (-4500ft/m) for about a minute. After this minute, I was again far below the profile. And this is where the problems started. As I was below the profile, the autopilot adjusted the vertical speed again to about -300ft/m. According to the blue arrow on the ND, I should have reached FL240 about 1NM before DENUT. But reaching that position, I was still at FL290. The blue arrow never moved from position, as I expected, depending on the VS. To help the aircraft to find back the profile I used VS. When I was back on the profile I used again managed descent. However, the same problem happened again over RIVER with the altitude constraint of FL070-FL100. In the end, I was able to land the aircraft without further assistance from the managed descent.
Are you able to reproduce the issue? If so, what are the exact steps you are taking for this issue to happen?
No - Reported immediately after flight.
The flight was done during evening time, so the pictures are a little bit to dark to upload them immediately. I've included all the screenshots I took in the attached ZIP file.