It is not about tools. It is about culture and process. Look at something like how SQLite for a real example of living up to the requirements of aviation softwa

It is not about tools. It is about culture and process. Look at something like how SQLite for a real example of living up to the requirements of aviation software: 100 % branch coverage, extensive testing, multiple independent platforms in the test suite etc etc. You don’t need anything fancy – but you do need to understand your requirements and thoroughly simulate and verify the intended behavior.