MEOLANS-REVELS, France, March 26 (UPI) -- The pilot who officials think deliberately put Germanwings Flight 9525 into a controlled descent and slammed it into a mountain in France appears to have reprogrammed the autopilot to do just that, reports said Thursday.
Tuesday's crash killed 150 people, including accused co-pilot Andreas Lubitz, in the French Alps after the flight's primary pilot left the cockpit for a few moments and ceded control. Investigators now believe Lubitz intentionally steered the Airbus A320 into the ground, following examinations of the cockpit voice recorder.
Thursday, officials said it became clearer that the crash was no accident. Lubitz is reportedly heard breathing on the voice recorder right up to the moment of impact, which suggests he was fully aware of the plane's rapid descent and did nothing to stop it.
Authorities are now digging into the 27-year-old Lubitz's background to determine why he may have wanted to take such an action. None of those who knew him noticed anything irregular or out of the ordinary regarding his behavior.
One acquaintance, however, said Lubitz had recently been depressed and that depression was "bad," the Los Angeles times reported.
Multiple news outlets reported Thursday that after the other pilot left, Lubitz reprogrammed the plane's autopilot to take the jetliner from 38,000 to less than 100 feet -- the lowest possible altitude setting. Lubitz's tinkering with the autopilot was also reported by FlightRadar24.com, a flight tracking forum.
Lufthansa, which owns Germanwings, said the unidentified primary pilot did not violate any security protocol by leaving the co-pilot alone on the flight deck. In the aftermath of 9/11, many carriers mandated that another crew member must reside in the cockpit if one of the pilots leaves, for security reasons. Officials said that was not the case, however, at Germanwings.
Since Tuesday's crash, multiple carriers have modified their policies to mandate the same thing.
Crew members aboard an Airbus A320 are provided with a backup option to gain access to a locked cockpit -- a keypad outside the door that, when prompted by the entry of a security code, opens on its own. However, the Washington Post reported that Lubitz overrode the keypad access to keep the door locked.
The Los Angeles Times reported that police served a search warrant on Lubitz's German apartment on Thursday, hoping to find clues as to why he may have crashed the plane. It was reported earlier that he started with Lufthansa in 2008, and then began training as a pilot -- training that was unconventionally interrupted for a few months.
Investigators and experts have speculated what might have happened immediately preceding the crash, but now most are convinced that it was a deliberate act. Some have speculated Lubitz was motivated by a desire to commit suicide, but the head of Lufthansa said that's a puzzling conclusion because one typically doesn't commit a suicide that also causes the deaths of 149 other people.
"If a person kills himself and also 149 other people, another word should be used, not suicide," CEO Carsten Spohr said.
"We are horrified that something of this nature could have been taken place," he added, in a report by the New York Times. "It is the worst nightmare that anyone can have in our company."
The cockpit voice recorder, in addition to capturing Lubitz's breathing, also relays sounds of the other pilot pounding violently on the door to get in and screams coming from the passenger compartment.
Reinforced and regularly locked cockpit doors are the result of the 9/11 terror attacks, as they are designed to keep plotters away from a plane's controls. But in this instance, some illustrate, that security measure played a direct and ironic role in facilitating Flight 9525's demise.
"The procedures put in place to prevent one bad thing from happening facilitated another bad thing happening," Jeff Price, an aviation management professor at Metropolitan State University of Denver, said in a Time magazine report Thursday.
"That act of fully locking the system down has made this event possible," added airline security expert Chris Yates. "Pilots use that access keypad ... but it can be overridden from inside. And that seems to be the problem."
Also Thursday, the U.S. State Department identified the third American who died in the crash as Robert Oliver.