The co-pilot of the Germanwings aircraft that crashed into the French Alps last week, killing all 150 people on board, had a medical exemption from work for the day of the crash but hid it from his employer, the German website Der Spiegel Online reported on Friday.

According to the report, German police discovered the medical exemption in the Dusseldorf apartment of Andreas Lubitz, 28, who a French prosecutor accused on Friday of deliberately flying the aircraft into a mountain.

German state prosecutors confirmed on Friday they had found evidence that Lubitz had hidden an unspecified medical condition from his employers.



"Documents with medical contents were confiscated that point towards an existing illness and corresponding treatment by doctors," said the prosecutors' office in Dusseldorf.

"The fact that there are sick notes saying he was unable to work, among other things, that were found torn up, which were recent and even from the day of the crime, support the assumption based on the preliminary examination that the deceased hid his illness from his employer and his professional colleagues," the prosecutors said.

A voice recording retrieved from the wreckage of the plane indicated that Lubitz deliberately locked the flight commander out of the plane's cockpit before initiating an eight-minute long descent into the mountain.

While police searched the properties in which the lived in Dusseldorf and the town of Montabaur on Friday, the German media speculated feverishly about Lubitz's alleged psychological problems, which are said to have included taking a year off from his pilot training program in 2009.

Carsten Spohr, CEO of Lufthansa, the parent company of Germanwings acknowledged on Thursday that Lubitz had interrupted his aviation training in 2009, but refused to say why.

Meanwhile, airlines around the world were scrambling on Friday to introduce new rules to increase aviation safety by ensuring that there are always two crew members present in the cockpit.

Emergency codes allow crew members to enter the cockpit when a pilot becomes incapacitated, but Lubitz is thought to have overridden this system, which was put in place after the September 11, 2001, terrorist attacks in the United States.

The German Aviation Association (BDL) was set to discuss the new rule with the country's civil aviation authority on Friday, with German carriers expected to change its procedures shortly thereafter.

Also on Friday, data from the transponder of the Germanwings plane confirmed that someone had manually altered the autopilot altitude to less than 100 feet (30 meters), a flight data organization said.

"Between 09:30:52 and 09:30:55 we can see that the autopilot was manually changed from 38,000 feet to 100 feet," said a post by FlightRadar24, which tracks aviation traffic, late Thursday.

"Nine seconds later the aircraft started to descend, probably with the 'open descent' autopilot setting," it said.

Germanwings flight 4U9525 left Barcelona around 10 am on Tuesday, and disappeared from radar around an hour later before crashing into a mountainside 165 kilometers north-east of the southern French city of Marseille.

The crash claimed the lives of 75 Germans, 50 Spaniards and citizens from 14 other countries, including one Israeli.