Europe's aviation watchdog recommended Friday that two people be present in plane cockpits at all times after a lone rogue pilot apparently deliberately crashed a Germanwings jet in March, killing all 150 people on board.

The European Aviation Safety Agency said pilots should "undergo psychological evaluation" during training or before entering service and face random drug and alcohol tests, although investigators have not cited those substances as factors in the Germanwings tragedy.

"This report is the result of a thorough analysis with practical recommendations so that such a tragic event does not happen again," EASA executive director Patrick Ky said in a statement.

Investigators say that 27-year-old German co-pilot Andreas Lubitz, who had a history of severe depression, intentionally slammed the Airbus A320 into the French Alps.

They say he locked the other pilot out of the cockpit when the latter went to the toilet on the March 24 flight from Barcelona to Duesseldorf, and then put the aircraft into a steep dive as his colleague tried desperately to get back in.

French prosecutors said Lubitz, who suffered from "psychosis," was terrified of losing his sight and consulted 41 different doctors in the previous five years, including psychiatrists and ear, throat and nose specialists.

Several of these doctors who were questioned by German investigators said Lubitz complained he had only 30 percent vision, saw flashes of light and suffered such crippling anxiety he could barely sleep.
Lubitz reportedly said "life has no sense with this loss of vision."

However the doctors he consulted -- including one who booked him off work two days before the ill-fated flight -- did not reveal his mental struggles due to doctor-patient confidentiality rules.

Immediately after the crash, the EASA published a "temporary recommendation for airlines to ensure that at least two crew, including at least one qualified pilot, are in the flight crew compartment at all times of the flight."

Many European airlines already enforced such a measure before the crash and others have adopted it since.

After a three-month review ordered by the European Commission, the EU executive arm, EASA confirmed the recommendation and said it would look at the situation again after a year.

- Oversight of tests -

Airlines will have to ensure that the psychological evaluations are carried out properly, it said.

More widely, it recommended "the establishment of a robust oversight programme over the performance of aero-medical examiners."

In addition, a "European aeromedical data repository" would be a step toward sharing medical information about airline crew.

Violeta Bulc, the EU commissioner for transport, welcomed the findings of the study undertaken at her request.

"If improvements are to be made in European safety and security rules or in their implementation, in order to help prevent future accidents or incidents, we will take the necessary action at EU-level," she said.

The watchdog carried out its review in parallel with the French investigation, whose final report on the crash is due in 2016.