It's not necessary to solve the halting problem to have the kind of protections aircraft have, let alone things like not drastically miscounting the stack space

It's not necessary to solve the halting problem to have the kind of protections aircraft have, let alone things like not drastically miscounting the stack space, having memory protection against stack overflow, using ECC RAM, not having 11,000 global variables, etc. Even if it was user error, this isn't even close to a sane design.