In their probe into the March 24 disaster, prosecutors in Dusseldorf found Lubitz had been diagnosed as suicidal "several years ago". He had recently been receiving treatment from neurologists and psychiatrists, who had signed sick notes a number of times. One of these, found torn-up in his apartment, was valid from March 16 to 29, prompting suspicions he had been hiding a mental condition from his employer. On Thursday, investigators said a tablet computer found at Lubitz' home showed he had been surfing the internet for information on suicide and cockpit doors.
Lufthansa says it knew nothing about the sick notes, and, in any case, under German law the documents would not have spelt out the reasons for his being unfit to work and the employer would have had no right to ask. The onus would have been on Lubitz to inform his boss - if he felt like it.
Germanwings' parent company is Lufthansa, a 60-year-old company that has a reputation for being bland but excellent on safety. That such a conscientious firm had been kept in the dark over Lubitz's mental problems has prompted calls for an overhaul of Germany's strict laws on medical secrecy, but others warn of the risk this could have for the doctor-patient relationship.
"In jobs where it is a matter of life or death, the doctor should be required to inform the employer that an employee is unable to work," Karl Lauterbach, the spokesman on health for the Social Democratic Party (SDP), which is in a governing coalition with conservatives, told reporters.
"This is especially so when it comes to cases of mental illness or a possible risk of suicide," said Lauterbach, a trained doctor and former professor of medicine.
His appeal found echoes within the SDP's coalition partner, the Christian Democratic Union (CDU), whose transport spokesman, Dick Fischer, said medical confidentiality should be eased in high-risk professions. "Pilots should go to doctors who are specified by their employer," he said. "These doctors should not be constrained from medical secrecy with regard to the airline and the federal aviation authorities."
But any tampering with rules on confidentiality is widely unpopular in a country with a traumatic history of snooping by Hitler's Gestapo or, in the former East Germany by the Stasi secret police.
In 2013 there was an outcry after whistle-blower Edward Snowden revealed the United States National Security Agency had been spying massively on Germany's public and Chancellor Angela Merkel.
Doctors' representatives are against any change, arguing that patients will hesitate to seek treatment for problems if they feel their boss will get to know about it - and things could thus be made much worse.
Medical secrecy "is a great benefit to the German public, and a human right", said Frank Ulrich Montgomery, president of the Federal Association of Doctors.
German law allows a doctor to alert authorities if it is suspected the patient has contracted an epidemic disease or is, or may be, planning a crime.
But in Lubitz's case, there had been no recent sign that he had intended to hurt himself or others, according to the investigation at this stage.
"The politicians are saying, 'let's change these rules, we need more security in this special area'. But the medical sector is saying, 'no way, never'," said Rene Steinhaeuser, a lawyer in Hamburg who specialises in medical law.
Steinhaeuser doubted whether change would be accepted by the public, given the intimacy between doctor and patient.
"What the security services are doing is abstract," Steinhaeuser told the Herald.
"When you are sitting there with your doctor, telling them what you feel, what you did, this is an absolutely different situation. There is much more sensitivity in this area."
