Arrange in order.
1. The EU and the European Aviation Safety Agency are now considering the introduction of a similar rule.
2. It underscores the fragility of the human factor which is truly the critical element in the rigorous processes required for aviation.
3. Significantly, last year's mysterious Malaysia Airlines MH 370's disappearance also involved a captain who may have been disturbed.
4. The Lubitz issue showed that the annual medical examination of pilots done under strict European Union regulations can fail to identify psychological problems such as depression.
5. Had the EU implemented a 'two-person' cockpit rule, such as in the U.S., which requires two crew members to be present in the cockpit always; this act of mass murder could have been stopped.

@mayur_arora I went through this question few days back. That's why I know about this article :P
@iswarnima omg