Large organizations often have cultures where seniority is required to effectively dissent. Sadly, NASA fell victim to this when diagnosing problems that led to the Columbia shuttle accident. This oversight has been predominantly attributed to a culture where the burden of proof fell on those raising concerns about debris hitting the leading edge of the wing, instead of on those maintaining that the status quo was safe and acceptable.
But, other large organizations seem to get it right. For example, the Naval reactors has the opposite culture. There, it's expected that everyone will raise potential risks no matter how small and the burden of proof lies on those defending the status quo. They place a strong emphasis on after action reports and critique. Additionally, they're in a separate chain of command to insulate them from pressure to green-light unsafe systems.