A350 Ultra Long Haul Issues

[YVNHWY]

Hello iniBuilds team,

I have now completed three full ultra‑long haul flights on the A350 in MSFS 2024 to identify the cause of severe FPS drops.

My config:
i7‑12700K
RTX 4070 12 GB VRAM
64 GB DDR5 RAM
All on SSD

Test 1 – SIN–JFK (Cabin ON)
Flight time: 18h10
Start of flight: Smooth, >40 FPS
After ~12–14 hours: FPS drop becomes noticeable
Landing: ~20 FPS
Arrival: Simulator crashed upon arrival at gate

Test 2 – SIN–JFK (Cabin ON, second try)
Flight time: 18h20
Same pattern: Smooth start, FPS drop after ~12-15 hours
Arrival: Simulator crashed on touchdown

Test 3 – JFK–SIN (Cabin OFF)
Flight time: 18h00
Entire flight: FPS stable from start to finish
Landing: No stutter, no FPS drop, no issues at all
Same settings, same weather, only cabin disabled

I was able to finish my 18-hour flight between New York and Singapore without any issues.

Conclusion
Across all the flights, the A350 cabin seems to be the primary cause of performance degradation on ultra‑long flights and I'm also assuming on 7h or 11h flights too.

Other addons I use (PMDG 777, Fenix A320, FSLabs A32X) all with detailed cabins and visible passengers (GSX) remain stable no matter the duration of the flight.

Suggestion

Possible Causes (from user observation)

• Dynamic memory build‑up: Cabin textures and geometry remain loaded in high detail for the entire flight instead of unloading/reducing when not visible.

• Cabin scripts/animations: Possible constant processing of animations, lighting, or passenger logic even when not visible.

• No purge of unused assets: Galley, toilets, and rear cabin sections likely remain active in memory through the flight.

• Potential MSFS sensitivity: The sim engine seems more sensitive to heavy, complex interior models (LOD handling differences vs PMDG/Fenix).

Suggestions for Optimisation

• Dynamic Cabin LOD
  Reduce cabin texture resolution and polygon count automatically in cruise.
  Apply aggressive LOD to hidden areas not visible from cockpit or exterior view.

• Memory Purge in Cruise
  Automatically unload unused cabin assets during cruise (rear galleys, certain textures).
  Reload before descent if needed.

• Cabin Lite Mode in EFB
  Option for simplified cabin model for long-haul flights.
  Keeps functionality but lowers GPU/VRAM load significantly.

• Light/Animation Optimisation
  Disable or simplify certain cabin lighting and animations during cruise to reduce processing overhead.

• General Memory Management for Long Flights
  Monitor and clear memory build‑up during extended sessions, similar to how PMDG, Fenix, and FSLabs manage long-haul stability.

Why this matters
This isn’t only for 18h flights like SIN–JFK — better cabin optimisation would improve stability on all long-haul flights (>6h) and ensure that even powerful PCs don’t suffer progressive FPS loss.

Otherwise, the plane is very realistic and cool. I have a friend who is a co‑pilot on the A350 and he confirms it. Of course, there are still some updates to come, but I love flying the A350, and those 18 hours were amazing!

Thank you for your work on this aircraft, I hope these tests and suggestions help improve long-haul performance.