Yep, unfortunately I don't know which OS they went for but it was one of the commercially-available RTOSes on the market. Those don't come cheap. Avionics soft

Yep, unfortunately I don't know which OS they went for but it was one of the commercially-available RTOSes on the market. Those don't come cheap. Avionics software certification is phenomenally expensive. Both Airbus and Boeing have warned in recent years that it has become such a big part of their development costs that they're concerned about it becoming unsustainable.