Co-pilot treated for suicidal tendencies.

Byline: Frank Jordans and Christoph Noelting

DUESSELDORF, Germany -- How could someone once diagnosed with suicidal tendencies get a job as a commercial pilot, entrusted with the lives of hundreds of people? That's the question being asked after officials confirmed Monday that Germanwings co-pilot Andreas Lubitz received lengthy psychotherapy several years ago.

All 150 people on board were killed by what prosecutors believe was a deliberate decision by Lubitz to slam the Airbus A320 he was flying from Barcelona to Duesseldorf into a mountain in the French Alps last Tuesday.

Lufthansa, Germanwings' parent company, declined to say whether it knew of Lubitz's mental health problems.

But it said the young pilot had passed all required medical checks since starting work for its subsidiary two years ago.

The country's aviation authority wouldn't comment on Lubitz's health, despite acknowledging last week that his record with the agency noted he needed ''specific regular medical examination'' beyond the annual checkup required of all pilots.

''The German Federal Aviation Office isn't directly responsible for assessing the air-medical fitness of pilots,'' said Cornelia Cramer, a spokeswoman for the agency, which is in charge of granting pilots' licenses.

Cramer said the medical checks are conducted by specially trained doctors, but declined to say whether their findings are passed on to the agency.

The head of the German Aviation Medical Practitioners Association, the organization representing doctors who determine if pilots are medically fit to fly, said the standard medical evaluation would not have been able to determine if a pilot suffered from a serious mental illness.

All pilots must undergo regular medical checks that include a cursory psychological evaluation, according to Dr. Hans-Werner Teichmueller, the agency's head.

But such tests rely on patients being honest with their doctors, and even a seriously mentally unstable person would have been able to put a ''mask'' on for the investigation, he said.

''You can't see anything beyond the face,'' Teichmueller said. ''We have developed a very refined system in Europe and most of us are in agreement that this system is optimal. If we were to add more psychological tests or modify the way we test, then we can still not change a situation like this.''

Prosecutors in Duesseldorf, where Lubitz had an apartment, said the psychotherapy he received took place before he received his pilot's license...