Getting the cabin atmosphere right in a flight simulator can be an important aspect of the experience for many simmers. But it’s easy to get into a situation where you load your flight, you remember to trigger the boarding music, then you forget the safety announcement, and by the time you’re at cruise, the immersion you were going for has already slipped away.
That’s the problem independent developer Stefan Simons set out to solve with 123FLIGHTSOUND, a free cabin sound utility for MSFS, and version 3.0, released a few days ago, is where the tool gets there.
The headline addition is a SimConnect-based auto-play system that reads live flight data directly from the simulator once per second and uses it to determine which of six flight phases you’re currently in: parked at gate, taxi out, cruise, descent, rollout, and parked arrival.
Each transition triggers the corresponding cabin audio automatically, from boarding music at the gate through to arrival announcements once you’ve rolled to a stop. “I wanted to create a tool where you just start it, load your flight, and forget about it,” Simons says. “v3.0 finally delivers that experience.”
There’s some thoughtful logic behind how the detection works. Phases only advance forward, so a brief drop in airspeed on climb won’t accidentally reset the sequence. The system filters out unstable sensor readings to prevent false triggers, and each audio file plays just once per flight session. The app also connects to MSFS automatically on startup and retries every five seconds if the connection drops, so there’s genuinely nothing to manage once it’s running.
On the audio side, announcements are structured around language-based packs rather than airline-specific ones, meaning they work across any livery or aircraft type. Custom sounds can be loaded in via the soundboard, and a knob-style mixer lets you balance cabin audio against engine sounds.
One current limitation worth knowing: the tool doesn’t work well in VR, where it renders as a separate window outside the headset. Simons has acknowledged this and says a fix is in progress.
123FLIGHTSOUND is free and open source, works with both MSFS 2020 and 2024, and the developer says it has zero FPS impact. Since its initial release just two weeks ago, it has already passed 1,200 downloads on flightsim.to. Check it out!
