Germanwings Co-Pilot Andreas Lubitz Appears to Have Deliberately Crashed Plane

Mr. Robin’s initial conclusions are drawn from the plane’s cockpit voice recorder, recovered at the crash site in the French Alps late Tuesday and analyzed by French accident investigators on Wednesday.

The co-pilot’s actions during the final minutes of the flight could be interpreted as a “willingness to destroy this aircraft,” Mr. Robin told a news conference in Marseille.

Mr. Robin said the investigation was focusing on the personality of the Mr. Lubitz, who only joined the airline in 2013. The prosecutor added that no elements suggest the crash was a terror attack.

The voice recording, which lasts over 30 minutes and includes the crucial last 10 minutes of the flight, contains screams believed to be from passengers once they recognized the plane was crashing.

Investigators are now exploring why Flight 9525, which had 150 people on board, went into its unauthorized descent from its 38,000-foot cruising altitude with one crew member absent. The descent led to the crash about 10 minutes later.

The prosecutor said people at the crash site had started recovering remains of victims and were still searching for the second black box that contains information on the Airbus A320’s systems and can provide further clues as to what happened.

Both the pilot and co-pilot were trained by the airline. The senior pilot, who hasn’t been name, had been with Germanwings since 2014 after flying for Lufthansa, the parent company of Germanwings, and Condor, another German airline. He has flown more than 6,000 hours, mostly on Airbus jets. Mr. Lubitz joined Germanwings in 2013 and had logged 630 flight hours.

Protected cockpit doors have become largely standard in the aviation industry after the Sept. 11, 2001 terrorist attacks in the U.S., when hijackers penetrated the cockpit and crashed the jets, causing the most fatalities ever in an aviation-related event. Regulators in most markets quickly moved to protect cockpits with secure doors.

Airbus won regulatory approval for its high-security door design in 2002. The door comes with an electronic entry pad that can be opened with a special access code from the outside, but the request can be denied from inside the cockpit by pressing a button within a few seconds after the request.

That is a security measure to prevent a person with knowledge of the access code being forced or coerced into opening the cockpit door from the outside.

When crew members try to access the cockpit from the outside a buzzer is triggered. Air accident investigators should be able to hear that sound on the cockpit recording.

Airlines in Europe have discretion over how they deal with one of the pilots leaving the cockpit. Lufthansa on Wednesday said that in certain phases of a flight, one of the pilots may leave the cockpit temporarily and that it is normal for the remaining pilot to be alone in the cockpit.

The revelation about the co-pilot came as the search-and-recovery operation resumed in the French Alps for the second straight day since the flight from Barcelona to Düsseldorf slammed into the mountain face.

Helicopter flights resumed Thursday from the alpine village of Seyne near the crash site, taking mountain rangers, forensic teams and other staff to recover bodies and body parts, said Col. Jean-Marc Menichini, the region’s police chief. “The priority is now to evacuate the bodies,” he said.

Forensic teams mapped out and photographed the crash site, tagged fragments and body parts and began removing the first human remains on Wednesday afternoon.

Weather conditions have improved, making the search-and-recovery mission easier. The location of the crash, on a steep slope, still makes the work dangerous for the forensic staff and investigators, who were working with ropes and crampon shoes.

The local chief of high-mountain rangers, Yves Naffrechoux, said officials spent the night on site to secure the area. Police officers are guarding all access to the site from lower in the hills to keep trespassers and journalists away, Mr. Menichini said.

The crash took a heavy toll on Germany and Spain, which had the most nationals on board. Family members of the victims are being brought to the crash site on Thursday.