Lufthansa knew six years ago that the co-pilot of the passenger plane that crashed in the French Alps last week had suffered from a "serious depressive episode," the German airline said Tuesday.

The airline said that as part of its internal research it found emails that Andreas Lubitz sent to the Lufthansa flight school in Bremen when he resumed his training there after an interruption of several months.

In them, he informed the school that he had suffered a "serious depressive episode," which had since subsided.

The airline said Lubitz subsequently passed all medical checks and that it has provided the documents to prosecutors. It declined to make any further comment.

The revelation that Lufthansa had been informed of Lubitz's psychological problems raises further questions about why he was allowed to become a pilot for its subsidiary, Germanwings, in September 2013.

Authorities say the 27-year-old Lubitz, who in the past had been treated for suicidal tendencies, locked his captain out of the cockpit before deliberately crashing the Airbus 320 into a mountain in the French Alps on March 24. All 150 people aboard Flight 9525 from Barcelona to Duesseldorf were killed.

Reports of recovered cellphone video

Separately Tuesday, German daily Bild and French magazine Paris Match said their reporters have been shown a video they say was taken by someone inside the cabin of the doomed plane shortly before it crashed.

Andreas Lubitz

Andreas Lubitz, the co-pilot of Germanwings flight 4U9525, is suspected of having deliberately piloted the plane into a mountain in southern France on March 24. (Getty Images)

Both periodicals reported that the video was found on a memory chip that could have come from a cellphone. Paris Match said the footage was found "among the wreckage by a source close to the investigation."

The Associated Press could not independently confirm the reports.

Marseille Prosecutor Brice Robin, overseeing the French criminal investigation into the crash, told the AP Tuesday night that no cellphone video has been found from the plane.

Lieutenant Col. Jean-Marc Menichini, a high ranking official involved in the recovery operation, categorically denied that any cellphone footage had been found by investigators at the site.

Lufthansa earlier Tuesday said it had set aside $300 million ($380.7 million Cdn) to deal with possible costs from the crash as French aviation investigators said they were examining "systemic weaknesses" like cockpit entry rules and psychological screening procedures that could have led to the Germanwings plane crash — issues that could eventually change worldwide aviation practices.

Possible international aviation changes

French aviation agency BEA signaled the latest re-think about airline procedures in the wake of the Germanwings crash, which jolted an aviation industry already reeling after one passenger plane disappeared into an ocean and another was shot out of the sky over war-torn eastern Ukraine.

'By the end of the week at the latest, it will be possible to identify all the victims thanks to the DNA samples taken.' — French President Francois Hollande

The goal of the BEA investigation is to make recommendations to aviation authorities, not just in France but anywhere, about what can be done to prevent similar crashes. French prosecutors are carrying out a separate crash probe to pinpoint possible criminal wrongdoing.

The Germanwings crash has already produced some changes in aviation procedures. Europe's aviation regulator now says all airlines in Europe should require two people in the cockpit at all times during a flight. Many airlines have already imposed the new rule, which has been in place in the U.S. since the Sept. 11 attacks.

The International Civil Aviation Organization, which brings together 191 nations, said state agencies like the BEA must officially determine the causes and contributing factors of crashes and give recommendations on ways to avoid recurrences. ICAO could then bring such recommendations to its member states — possibly leading to changes in international aviation standards.

BEA said it aims to provide a "detailed analysis" of the Germanwings cockpit voice recorder and any other flight data — but it also plans to widen its search, to examine issues that could be problematic for all airlines.

"[We will study] systemic weaknesses [that] might possibly have led to this aviation disaster," BEA said in its first statement since prosecutors detailed the co-pilot's suspected role in the crash.

The agency is studying both psychological screening procedures and rules applied to entering and leaving the cockpit, as well as cockpit door locking systems.

'Suicidal tendencies'

German prosecutors say Lubitz received psychotherapy before obtaining his pilot's license and that medical records from that time referred to "suicidal tendencies." They have given no dates for his treatment, but said visits to doctors since then showed no record of any suicidal tendencies or aggression against others.

Germanwings France Plane Crash

A black Germanwings logo is, center, is placed between candles, flowers and messages for the victims of the plane crash at the airport in Dusseldorf, Germany, on March 31, 2015. (Martin Meissner/Associated Press)

They also have found torn-up sick notes from doctors, including one that would have kept Lubitz off work on the day of the crash.

At the crash site in the French Alps, investigators said they hope to have found DNA samples for everyone killed on the flight in the next 24 hours. Lt. Col. Jean-Marc Menichini, speaking in the town of Le Vernet, said the search was still on for the plane's second black box — its data recorder.

"By the end of the week at the latest, it will be possible to identify all the victims thanks to the DNA samples taken," French President Francois Hollande told reporters during a trip to Germany.

Hollande said German and French ministers also discussed the need to improve checks of air passengers within Europe's visa-free Schengen travel zone and to "ensure that we can also strengthen our safety rules for piloting planes."

Recovery efforts continue 

Construction workers have cut a road up to the steep, mountainous crash site to speed up recovery efforts. Previously, emergency workers had to rely on helicopters. German investigators tasked with identifying the victims and determining their cause of death are expected Wednesday at the crash site.

Lufthansa — Germanwings' parent company — offered immediate aid last week of up to €50,000 ($68,630 Cdn) per passenger to relatives of the victims. Those payments are separate from eventual compensation payments.

Airlines on international flights are required to compensate relatives of victims for proven damages of up to a limit of about $157,000 ($199,000 Cdn) — regardless of what caused the crash. However, higher compensation is possible if a carrier is held liable.

Lufthansa has canceled plans to celebrate its 60th anniversary on April 15 "out of respect for the victims of the crash."