In response to prosecutors' allegations that co-pilot Andreas Lubitz deliberately crashed the Düsseldorf-bound Germanwings plane on March 24 on a day that he was supposed to be off sick, the head of the German Pilots' Doctors Association urged more thorough examinations.
"We are calling for more frequent and comprehensive laboratory tests for pilots," the association's chief Hans-Werner Teichmüller told Welt newspaper.
"We need to see results that can also show traces of psychotropic drugs and narcotics."
But a spokesman for pilots' union Vereinigung Cockpit told The Local on Tuesday that it was too soon to decide on particular measures.
"It's true that we now know how the accident happened, that it was on purpose, but we don't know what caused it - whether [Lubitz] was depressed or suffering from something else," he said.
"We need to find out what happened, and then get the doctors, the pilots, the authorities together and decide how we can reduce the risk of this happening again."
The spokesman added that there should be "no taboos" when considering possible fixes to the health system for pilots.
'Only indirect evidence'
Current annual physicals required of pilots only include a test of urine, haemoglobin levels and in some cases blood sugar.
If a standard blood test is ordered, only indirect evidence of excessive alcohol consumption can be identified and no evidence of drug use, according to Welt.
Teichmüller said that key data on the liver, kidneys and cholesterol levels were also absent from a typical medical file kept on pilots.
In the immediate aftermath of the catastrophe, the association's vice president, Uwe Beiderwellen, had said that he opposed routine psychological tests for pilots.
Germanwings parent company Lufthansa acknowledged last week that Lubitz had informed its flight school in mid-2009, when resuming training after a lengthy medical absence, that he had suffered from a "previous episode of severe depression".
He later received the medical certificate confirming he was fit to fly.
German prosecutors said that Lubitz was diagnosed as suicidal "several years ago", before he became a pilot, but doctors had recently found no sign he intended to hurt himself or others.
However Lubitz was receiving treatment from neurologists and psychiatrists who had signed him off sick from work a number of times, including the day of the crash.
Ripped up sick notes were found in a flat used by Lubitz, which authorities believe indicates that the 27-year-old was trying to hide his illness from his employer.
A spokeswoman for the Federal Aviation Office (LBA), which issues pilots' licences, told AFP on Sunday that Lufthansa had given it "no information about the medical background" of Lubitz.
Citing medical files obtained by investigators, Bild daily reported last week that Lubitz told his doctors he was on anti-depressants and Lorazepam, a mild tranquiliser used to treat anxiety.
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