A top airline executive admitted yesterday that the co-pilot behind the Germanwings air disaster had slipped through the safety net.
Speculation has been mounting about the mental state of Andreas Lubitz, who flew the airliner into the French Alps on Tuesday, killing 150.
Carsten Spohr, th head of Germanwings parent company Lufthansa, said: "The pilot had passed all his tests, all his medical exams. He was 100 per cent fit to fly without any restrictions .
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"We have at Lufthansa, a reporting system where crew can report – without being punished – their own problems, or they can report about the problems of others without any kind of punishment.
"All the safety nets we are all so proud of here have not worked in this case."
Lubitz was silent but breathing for eight terrifying minutes after he locked the captain out of the cockpit and initiated the landing procedure on Tuesday.
Mr Spohr said the 28-year-old had been working as a flight attendant when he first tried to become a pilot in 2008, after waiting eight months.
But his training was "interrupted", Mr Spohr said.
"I cannot tell you anything about the reasons of this interruption," he added.
"But I told you before that anybody interrupts the training has to do a lot of tests so the competence and fitness would be checked again."
Lubitz eventually gained a position as a first officer on board Airbus A320s in 2013, Mr Spohr said.
Mr Spohr said Lubitz and the captain who died alongside him in the French Alps on Tuesday had gone through training in Bremen, Germany, and Phoenix, Arizona.
Both pilots took the DLR psychiatric test which is standard throughout the airline industry.
"His performance was without any criticism," Mr Spohr said. "Nothing at all was striking.
"Not in our worst nightmares would we ever have imagined such a tragedy.
"In a company like ours where we are so proud of our selection criteria, our safety criteria, this is even more of a shock for us than it is for the general public."