Günter Lubitz told reporters in Berlin on Friday that he was “on a hunt for the truth” two years to the day after his son Andreas is believed to have deliberately crashed a passenger plane into the Alps, killing himself and 149 other people.
"We have to live with the fact that we not only lost our son, but also that it was concluded two days after the fact that he was a depressed mass murderer," Lubitz, who bears a striking physical resemblance to his son, told the packed hotel conference room.
Investigators have said that when the senior pilot temporarily left the cockpit to use the bathroom, the 28-year-old co-pilot refused to let him back in, overriding the code he entered on the locked door. While the captain was locked out, officials say Andreas initiated the plane's descent.
But the co-pilot's father set out the following points to make his own case.
‘Andreas wasn't suffering from depression'
Günter Lubitz told reporters that his son was not suffering from depression at the time of the crash, despite the media “characterizing him as permanently depressed.”
He said that his son was on the contrary “optimistic” at the time.
“He was a very responsible person,” Günter Lubitz told Die Zeit the day before the press conference, adding that the idea he was a mass murderer “simply doesn't correspond to his personality.”
Three days after the crash, the Berlin daily Tagesspiegel reported that Lubitz had been in treatment for depression at the time of the crash, but had hidden the illness from the airline.
It has been confirmed that Lubitz interrupted flight training in 2009 due to depression and that he informed Germanwings parent company Lufthansa.
But prosecutors have never said what type of illness Lubitz was in treatment for at the time of the crash.
Nonetheless Christoph Kumpa, the Düsseldorf prosecutor who led the German investigation, rejected the relevance of this detail.
“We never claimed that he was depressive," Kumpa said on Thursday.
The prosecutor said that he could not reveal the illness Lubitz was being treated for because of patient confidentiality, but said it commonly led to treatment with antidepressants.
A report in Spiegel on Friday claims prosecutors believe Lubitz suffered from an anxiety disorder.
Kumpa said on Friday that Lubitz had “suffered for months from insomnia, was anxious about his eyesight, and was suffering doubt."
Furthermore, the co-pilot had looked up suicide methods on the internet and ways of locking a cockpit door, the prosecutor added.
‘Prosecutors jumped to conclusions'
Günter Lubitz assigned Berlin aviation expert Tim van Beveren to look into how prosecutors in France and Germany had conducted their investigation.
At Friday's press conference, van Beveren accused investigators, in particular Marseille public prosecutor Brice Robin, of zeroing in on Lubitz from the start of the probe.
"Everyone heard that and wrote it - and everyone believed it," he said. "We all have theories, but theories are not proof."
Van der Beveren claimed during the press conference that there had been problems with the airplane in question before the crash, saying that a crew had previously locked themselves inside the cockpit by mistake and were unable to get out.
He also said that evidence taken from the plane's black box, which records sound in the cockpit, proved that Lubitz was alive at the time of the crash. But the breathing which was heard on the recorder did not prove he was conscious, he added.
The private investigator went further, saying that there was not even proof that Lubitz was the person in the cockpit.
But the Frankfurter Allgemeine Zeitung reports that there is more evidence to suggest that Lubitz was the person in the cockpit and that he intentionally crashed the plane.
On the black box, the pilot can be heard trying to get back inside, banging on the door and shouting.
On the flight to Barcelona earlier in the day, Lubitz also temporarily set the flight height to 30 metres altitude before changing it back. According to van der Beveren, this could have been “only a game.”
Furthermore, the person in the cockpit increased the speed of the plane before the crash, suggesting he was conscious.
Van der Beveren conceded that he had no alternative scenario for what could have happened.
“I don't know what happened, nobody knows,” he said.
But he insisted that “if [Lubitz] had survived, he would have been acquitted in ten minutes in court.”