The investigation into Germanwings Flight 4U9525 took a disturbing turn on Thursday when French authorities announced that the captain of the doomed flight was intentionally locked out of the cockpit in the final minutes before the fatal crash that killed 150 people.

What's known about the crash is now focusing attention on two potential flaws in airline systems: cockpit security and pilot psychological evaluations.

French public prosecutor Brice Robin, who cited evidence from the the flight's voice recorder, claimed the co-pilot, who was identified as 28-year-old Andreas Lubitz, ignored the captain pounding on the door in the last eight minutes of the flight and "voluntarily" sabotaged the flight, according to the Guardian. Lubitz could be heard breathing right up until the point of impact, meaning that he had not lost consciousness from the cabin becoming depressurized. He failed to respond to the captain trying to break down the door and launched the five-minute override of the captain's access code when the captain attempted to re-enter the cockpit, according to Lufthansa CEO Carsten Spohr.

In a press conference Mr. Spohr, confirmed that the flight crash was likely a suicide/homicide, and that the airline would review its policy regarding maintaining a certain number of crew members in the cockpit at all times. Spohr also said that the airline's psychological screening process for pilots would be reviewed, while maintaining he had full confidence in the process.

On Thursday, Canada and Germany's biggest airlines, including Lufthansa and Air Berlin, as well as low-cost European carriers Easyjet and Norwegian Air Shuttle announced new rules requiring two crew members to always be present.

Since Sept. 11, 2001, commercial airline passenger aircraft installed a mechanism on the door with a passcode to prevent a hijacker from entering the cockpit. On the aviation forum airlines.net, one commenter, who writes under the screen name CALTECH and says that he has been working with US airlines since 1985, wrote that there was nothing the crew locked out could have done to regain control of the aircraft.

All it takes is for someone in the cockpit to move the switch to 'LOCK' and the keypad, routine and emergency access are disabled for a period of time, time enough for what happened. You can not get access to the cockpit if the someone inside the cockpit does not want you in. No override is possible. No code will override the person in the cockpit. Even the escape hatch routine has to be performed from inside the cockpit.

This crash raises the issue of how comprehensively pilots are psychologically evaluated, which varies depending on the airline and the home country's requirements, according to CNN.

For instance, in the United States, the Federal Aviation Administration (FAA) requires pilots to receive psychological evaluations as part of their annual physicals, as well as requiring them to disclose any mental health issues they may be facing in addition to any medication they take. Then, any potential red flags are passed on the FAA flight surgeon.

"I flew for over 20 years. I don't think I had any further in-depth psychological screening from the FAA," former pilot Mark Weiss, a CNN aviation analyst, told the network. "The most that would happen would be, the FAA examiner would ask me, 'How is everybody at home? Things going okay?'"

Mr. Weiss says that instead of the FAA conducting in-deph psych evaluations, these screenings are done more so by the airline when a new pilot is hired and is then left to the doctors performing the subsequent physicals.

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In 2012, Clayton Osbon, the 49-year-old captain of a New York-to-Las Vegas flight, started ranting about a bomb aboard and screamed, "They're going to take us down!" A co-pilot locked him out of the cockpit and guided the plane to an emergency landing in Amarillo as passengers wrestled Mr. Osbon to the floor. He was carried off the plane and taken to a hospital. JetBlue told the Associated Press that Osborn had suffered a "medical situation."

This current approach to evaluating the pilots' mental wellbeing may get revised in the coming months following the Germanwings crash, which now appears to be a tragic combination of one man acting on his own and the best-intended cockpit safety features thwarting the pilot from regaining control of the aircraft. Prophetically, a similar scenario was postulated by 2014 Popular Mechanics story, following the disappearance for Malaysia Airlines flight 370 – which as not yet been found.