Günter Lubitz, the father of Germanwings co-pilot Andreas Lubitz, has called a press conference in Berlin for this Friday - the second anniversary of the crash that killed 150 people - to present his own findings into the disaster.

Lubitz is planning to challenge a German criminal investigation into the crash, which concluded in January that his suicidal son bore sole responsibility for crashing the Airbus A320 into the French Alps.

The probe focused on whether doctors who have treated the 27-year-old had been criminally negligent in not reporting him to authorities.

Germanwings crash: Investigators call for new mental health checks for pilots Doctors must report mentally ill pilots The BEA air investigation agency said new guidelines were needed to ensure pilots are properly screened for serious mental health conditions. Doctors should warn authorities if a pilot's psychological state poses a threat to public safety, the report said. But it stopped short of calling for regular psychiatric tests for all pilots.

Germanwings crash: Investigators call for new mental health checks for pilots Lubitz had 'psychotic' incident before crash The French report revealed how co-pilot Andreas Lubitz was advised to seek treatment at a psychiatric clinic just two weeks before the crash. Investigators said doctors had described his symptoms as compatible with a psychotic episode. Despite a history of depression and the fact he was on two antidepressants at the time of the crash, none of his doctors reported their concerns to authorities.

Germanwings crash: Investigators call for new mental health checks for pilots Pilots' privacy or passengers' safety? Arnaud Desjardins, the head of the French investigators, said on Sunday that the pilot certification process failed to identify the risks posed by Lubitz' severe depression. Germany's confidentiality laws were especially strict and clearer guidelines were needed to establish when public safety outweighed patient privacy, the report said. Germanwings maintains it knew nothing of Lubitz' illness.

Germanwings crash: Investigators call for new mental health checks for pilots Flight 9525's 10-minute descent On March 24, 2015, Germanwings Flight 9525 crashed in the French Alps during a flight from Barcelona to Düsseldorf. It was carrying 144 passengers and six crew, mostly Germans and Spaniards. Within hours, French investigators said they believed the co-pilot had deliberately caused the tragedy by locking the pilot out of the cockpit and setting the autopilot to a height of just 100 meters (328 ft).

Germanwings crash: Investigators call for new mental health checks for pilots Murder-suicide at high speed At 10:31 CET, Flight 9525 left its cruising altitude of 12,000 meters (38,000 feet) and began to descend rapidly. French air traffic controllers attempted to make contact but there was no response from the flight deck. Later, audio from the black box flight recorder revealed how the pilot attempted to get back into the cockpit, while Lubitz' breathing remained steady throughout the descent.

Germanwings crash: Investigators call for new mental health checks for pilots No new cockpit rules recommended The French report did not request a change to cockpit security, despite Lubitz being able to lock the plane's pilot out of the flight deck. The locking system was introduced to keep hijackers from gaining access to the cockpit after 9/11. Following the Germanwings crash, several airlines have made it compulsory to have two people in the cockpit at all times during the flight.

Germanwings crash: Investigators call for new mental health checks for pilots Families want lessons learned Lawyers for the victims' families say Lubitz' doctors, a US flight training school and the airline were responsible for failing to detect, and act on, his psychological problems. Lubitz had suffered a severe depressive episode during his pilot's training in 2009. The families were informed of the details of the report on Saturday in Barcelona and Bonn, a day before its release.

Germanwings crash: Investigators call for new mental health checks for pilots Victims' remains brought home The remains of 16 German teenagers and two teachers who had been in Barcelona on a school exchange and were killed in the crash traveled in a convoy of white hearses when they arrived back in Germany two months after the crash. In their home town Haltern, 18 trees - one for each victim - have been planted outside their school.

Germanwings crash: Investigators call for new mental health checks for pilots New start for the low-cost carrier Since the tragedy, Germanwings has rebranded and become Eurowings. On Sunday, its parent company Lufthansa welcomed the French recommendations. In a brief statement, the German carrier said that "ensuring the highest possible flight safety was and remains our utmost priority." The company said it would "support the possible implementation of concrete measures" based on the BEA report.

Germanwings crash: Investigators call for new mental health checks for pilots Flight 9525 victims remembered A monument in memory of the victims stands in the village of Le Vernet in southeastern France. Located close to the mountainous crash site, the tiny hamlet has become a permanent place of memorial for many of the relatives. Over the past year, several trips have been arranged to help the families of those killed get some sort of closure after the tragedy. Author: Nik Martin



Father unconvinced

"Up to now, everyone believes the theory of a co-pilot who was depressed for a long time, who deliberately crashed his plane into a mountain in a planned act. We are convinced this is false," the father said in a press release.

Günter Lubitz will be joined on Friday by journalist Tim van Beveren, who he called "an internationally recognized aerospace expert."

He said many questions remain unanswered and certain aspects of the investigation have been ignored.

Investigators have said Andreas Lubitz deliberately set the plane's controls to plunge into the mountains during a scheduled flight from Barcelona to Dusseldorf on March 24, 2015.

'Timing is wrong'

A lawyer for relatives of the crash victims told the regional paper "Rheinische Post" that the timing of the father's challenge to the official investigation was "very unpleasant."

"To do this exactly two years to the second that the plane crashed is irresponsible. From the victims' point of view, this is tasteless and likely to be traumatic for many of them," said the Berlin-based attorney Elmar Giemulla.

An investigation found that co-pilot Andreas Lubitz had mental health issues several years before the disaster

Giemulla added that the father was trying to spread a theory that "frees his son of all responsibility."

Andreas Lubitz's parents had already angered the families last year when they placed a heartfelt newspaper announcement in their son's memory to mark the first anniversary of the crash.

Without mentioning the victims of the crash, the ad entitled "Andreas," showed a smiling photograph of the co-pilot with the message: "We miss you very much, but you are and will remain in our hearts".

Ongoing legal cases

A separate manslaughter investigation is underway in France, while a lawsuit has been filed against the Lufthansa-owned flight school that trained Lubitz, after it was revealed he had been treated for suicidal tendencies prior to his training. He had also been temporarily denied a US pilot's license due to depression.

In the days before the crash, the probe found Lubitz, who believed he was going blind, researched online ways of committing suicide. A doctor's letter was found at his home declaring him unfit to work.

As well as the press conference, a memorial service is due to be held at the crash site on Friday, attended by many of the victims' families.

mm/gsw (AFP, dpa)