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Seeking to ensure that suicidal pilots can't crash their jets, French authorities investigating last year's Germanwings crash are urging new reporting requirements for doctors treating pilots, and new measures to keep pilots from hiding mental health issues.

The recommendations are delicate. The investigators from France's BEA air accident agency acknowledged Sunday that it's not easy to balance patients' right to medical privacy and public safety, and said they don't want to stigmatize people suffering depression.

But they argue that aviation authorities around the world need clearer rules, after Germanwings co-pilot Andreas Lubitz locked his captain out of the cockpit and slammed Flight 9525 into an Alpine mountainside March 24, 2015. All 150 people aboard were killed.

Lubitz had suffered from depression in the past, but authorities and his airline later deemed him fit to fly. What they didn't know is that his mental health troubles had returned.

The final crash report released by the BEA Sunday lays out in chilling detail how bad things had become.

Lubitz consulted dozens of doctors about perceived vision troubles and sleeplessness in the months leading up to the crash. One doctor prescribed antidepressants, including one whose side effects can include suicidal tendencies. Another doctor referred Lubitz to a psychiatric clinic two weeks before the crash, suspecting a potential "psychotic episode," said Arnaud Desjardin, leader of the BEA's Germanwings investigation.

Lubitz reported none of this to Germanwings or its parent Lufthansa. Neither did the doctors, citing Germany's strict medical confidentiality laws.

The BEA says those rules need to change.

Among a list of 10 safety recommendations to international, European and German aviation authorities, the BEA said they should draw up new rules requiring medical workers to warn authorities when a pilot's mental health could threaten public safety.

It suggested more rules like those in the U.S. and some other countries, which allow use of some antidepressants under medical supervision, to encourage pilots to seek treatment and come forward about depression.

Germany's confidentiality laws prevent sensitive personal information from being widely shared, though doctors are allowed to suspend patient privacy if they believe there is a concrete danger to the person's safety or that of others.

Desjardin said German doctors fear losing their jobs or potential prison terms if they unnecessarily report a problem to authorities. The doctors who treated Lubitz for depression and mental illness also refused to speak with the BEA investigators, citing medical privacy — and complicating the investigation.

Johann Reuss of Germany's air accident investigation agency told The Associated Press "there is no need to change the law." Reuss said "it might not be easy" to loosen the privacy rules and suggested that authorities instead focus on giving doctors checklists to prevent similar scenarios with pilots.

The BEA safety recommendations also include special insurance options and peer support groups for aviation workers, to ease concerns about losing a job that pilots with mental health issues face.

Even though Germany's medical privacy laws are stricter than those in the U.S., it's hard to imagine a U.S. doctor reporting mental health concerns about a pilot to an airline or the FAA without his patient's permission, said John Gadzinski, an veteran U.S. airline pilot and safety consultant.

The underlying problem is that society hasn't figured out how to deal with mental health in a way that protects both the patient and society, Gadzinski told the AP from his home in Virginia Beach, Virginia.

"I think the Germanwings accident is more of a symptom than the major issue," he said. "The major issue is how do we deal with mental health."

Jim McAuslan, general secretary of the British Airline Pilots Association, said in a statement, "Pilots welcome recommendations to introduce peer support programs for pilots across the aviation industry. ... By encouraging those with mental health problems to seek help, offering them treatment and ensuring they do not suffer financially if they do come forward, we prevent these issues being driven underground."

The BEA also recommended more frequent, deeper monitoring of pilots who had mental health issues in the past — for example every three months instead of every year. Lubitz' relapse appeared to begin around four months before the crash.

The agency said airplane cockpit security rules shouldn't be changed, saying hijacking remains a greater threat than pilot suicide. Current cockpits are equipped with a code system to prevent the kind of hijackings that occurred on Sept. 11, 2001, in the United States, where planes full of passengers were turned into weapons.

After the Germanwings crash, some airlines required that at least two people be in the cockpit at any given time.

Lufthansa pledged to back the new safety recommendations. Since the crash, the airline has replaced its Germanwings brand with the name Eurowings.

On the day of the flight, Lubitz rehearsed a similar crash a few hours earlier. Then half an hour after Flight 9525 took off from Barcelona, Capt. Patrick Sondenheimer handed the controls to Lubitz and went to the restroom. Lubitz quickly locked the cockpit and set the plane into an accelerated dive for a mountainside near the French village of Le Vernet, where a stone memorial to victims marks their memory.

Traces of anti-depressive medications Citalopram and Mirtazapine were found in Lubitz's remains, as well as the sleeping medication Zopiclone, the BEA report says. The U.S. National Library of Medicine notes on its entry for Citalopram that children and young adults who take the drug can become suicidal.

Lubitz was 27 when he crashed the plane.

The BEA investigation is separate from a manslaughter investigation by French prosecutors seeking to determine eventual criminal responsibility. Lufthansa strongly denies any wrongdoing, but relatives of those killed have pointed to a string of people they say could have raised the alarm and stopped Lubitz, going back to the days when he began training as a pilot in 2008.

Families of Germanwings victims met with BEA investigators Saturday, but many were disappointed in the explanation.

"Some of the family members felt as if these BEA representatives were Lubitz's lawyers — making excuses as to why Germanwings didn't take action knowing what they knew," Robert Tansill Oliver, whose son died in the crash, told the AP.

"How is it possible Germanwings would let a crazy guy fly a plane? He was mentally unbalanced, tremendously unbalanced," Oliver said.