Formal methods are indeed hard. They generally thrive on hardware, software is a wholly different kettle of fish in terms of the size of the problem (the actual methods are often similar, but hardware design generally encourages certain patterns that are easier to analyse)

I'm not related to this project or aerospace, so I can't divine more knowledge than anyone else, although I have seen many coding standards that forbid malloc after some critical time (e.g. no dynamic memory allocation after the plane is off the ground)