German pilot said to have suffered from depression, anxiety

Family and relatives of the victims of the Germanwings plane crash in the Alps are taken on bus to the Prat airport from a hotel in Castelldefels in Barcelona, Spain, to take a Lufthansa flight to visit the crash site in Seyne les Alps in France, March 26, 2015. [Photo/IC]

Randy Knipping, a Toronto-based specialist in aviation medicine, said it was extremely difficult to conduct screening for psychiatric problems among pilots, in part because they can put their careers in jeopardy by admitting to such problems.

"If somebody wants to withhold or conceal, there's no reasonable test," he said, adding that unless a family member comes forward to flag a mental problem, then problem cases can "slip through".

In Montabaur, a small town of 12,000 near the Rhine River, friends who knew Lubitz at the local flying club were stunned and saddened. Some pleaded with reporters who descended on the town not to rush to judge Lubitz until all the facts are known.

He appears to have had an active lifestyle, running a half-marathon in a good time and showing an interest in pop music and night-clubs, according to his Facebook page, which also featured a photo of Lubitz by the Golden Gate Bridge in San Francisco.

"I'm just speechless. I don't have any explanation for this. Knowing Andreas, this is just inconceivable for me," Peter Ruecker, a long-time member of the flight club, told Reuters.

Germanwings has so far released few details of the co-pilot, who had only 630 hours of flying time to his name, unlike the captain who had flown for more than 6,000 hours and had worked for Lufthansa for 10 years.

Lubitz was trained at the Lufthansa pilot training academy in Bremen, which declined to talk about him, as well as in Arizona.

After news of the crash, his local flight club in Montabaur put a black ribbon on its website with the flight number and the name "Andreas". But the website was no longer accessible on Friday.