The tragic irony from Germanwings crash in the French Alps this week, assuming that the scenario of the co-pilot’s reckless suicide proves the most prevalent, is the fact that the impassable cockpit door was a result of safety measures instituted after 9/11.

In the wake of the simultaneous terrorist hijackings back in 2001, aviation officials and airline companies made entry into an airliner’s cockpit almost impossible for would-be hijackers.

The fact that a codepad sequence to open the cockpit door was overridden by the co-pilot remaining at the helm is one such safety facet, ostensibly to prevent anyone from seizing a crewmember and forcing them to enter the code for access to the cockpit.

That’s apparently what 28-year-old co-pilot Andreas Lubitz did when pilot Patrick Sonderheimer tried to re-enter the cockpit after a toilet break.

ICAO clarified on Thursday amid the furor over the crash that when a crewmember needs to get into the cockpit and doesn’t know or remember the access code, a simple knock on the door or pushing an electronic ringer will suffice.

Nevertheless, according to experienced flight crewmembers, a pre-arranged password or even a set of passwords are agreed to in crew meetings before every flight. Moreover, most modern airliners also give pilots a camera view of the area just outside the cockpit door.

Meanwhile, according to media reports, the parents of co-pilot Andreas Lubitz learned that authorities suspected their son crashed the plane into the mountainside only moments before a press conference by the Marseilles prosecutor on Thursday.

They couple were told of the information before it was made public to a throng of waiting reporters and television cameras.

Lubitz’s parents had traveled to the French port city along with family members of other victims, but immediately departed after the revelations from data reprieved from the plane’s “black box” in order to avoid possible tension.

Eyewitnesses present during the Lubitz couple’s briefing by French authorities appeared shocked, according to the Daily Mail.