Investigators announced today that the plane crash in the French Alps was an intentional act by the first officer. It happened while the captain was locked out of the cockpit and unable to regain entry.

After the terrorist attacks in 2001, hardened cockpit doors were universally lauded as a sensible anti-terrorism measure. It is clear from this incident that there is at least one drawback: they fundamentally undermine one of the safety benefits of the 2-pilot system. I have to wonder, will anyone publicly revisit this discussion?