A stock image of an Airbus A320 cockpit. The black box of Flight 4U9525 revealed frantic attempts by the pilot to re-enter the cockpit. (AAP)
Germany's aviation association BDL has announced plans to introduce a two-person cockpit rule after it emerged that the co-pilot on a Germanwings flight deliberately crashed after being left alone.
The announcement was made by the federation's chief Matthias von Randow, a BDL spokeswoman told AFP.
The new policy would require two crew members to be in the cockpit at all times. The second person could be a flight attendant if the pilot or co-pilot has to exit the cockpit in flight.
Separately, the head of Germanwings' parent company Lufthansa, Carsten Spohr, said the two-person cockpit rule would be discussed at an industry meeting on Friday to be attended by the Federal Aviation Office (LBA).
The meeting will focus on "ways that could in the short term help increase security" on planes, Spohr told German public television ARD.
Earlier today, the Canadian government and several European airlines, including easyJet and Norwegian Air Shuttle, announced that they were introducing the "rule of two" on all their flights.
The policy changes came after French authorities said the co-pilot of the doomed Germanwings flight appeared to have intentionally slammed his Airbus A320 into the French Alps, killing all 150 passengers and crew.
The 28-year-old initiated the plane's descent while alone at the controls and refused to open the locked cockpit door for the captain, who was believed to have gone to the toilet.