Co-pilot's four 'cold' words before crashing plane into mountain killing all passengers

A harrowing Sky documentary has delved into the tragic tale of Germanwings Flight 9525, which plunged into the French Alps on March 24, 2015.

The plane, which was en route from Barcelona to Dusseldorf, met a horrifying end when it crashed at 430mph, killing everyone aboard.

What started as a routine flight for the passengers and crew turned into disaster just one hour post-departure as Flight 9525 was obliterated against the mountainous terrain.

The subsequent investigation unearthed shocking revelations through the black box data, unveiling that co-pilot Andreas Lubitz deliberately orchestrated the crash.

In the wake of this revelation, aviation regulations were immediately reformed to prevent a pilot from remaining alone in the cockpit, reports the Daily Record.

The doomed aircraft lifted off at 10am local time and last contacted air traffic control 30 minutes later.

Tragically, it was following Captain Patrick Sondenheimer's exit to the lavatory and Lubitz's fateful decision to lock him out of the cockpit that the descent began. The chilling final words recorded by the cockpit voice recorder were from Lubitz: "You can go now."

Sondenheimer entrusted Lubitz with radio communications just before stepping out at about the 28-minute mark, shortly before the sound of the cockpit door signifies its closure.

At this juncture, Lubitz altered Flight 9525's altitude from 38,000 feet 100 feet before initiating a descent into the mountains, disregarding all communication attempts from air traffic control as the plane plummeted towards the earth.

The co-pilot remained ominously silent for the remainder of the flight while Sondenheimer can be heard pounding on the door in a desperate bid to regain access to the cockpit.

However, the captain's efforts proved futile as Lubitz had also bypassed the emergency access codes which would have permitted the flight crew entry to the cockpit.

This left him alone in the command centre with complete control over the aircraft. As Sondenheimer's desperation escalated, he can be heard bellowing, 'open the damn door' whilst continuing his attempts to breach it.

In the final moments captured on the recording, passengers can be heard screaming just before Flight 9525 crashes into the mountainside. This chilling sound suggests many were oblivious to the impending disaster until the very last moment.

In the wake of the crash, it emerged Lubitz had been battling severe depression and had shown signs of suicidal tendencies.

He had been deemed unfit to fly by his doctor but this crucial information had been concealed from his employer.

Following the incident, there was increased dialogue around medical confidentiality and new policies were introduced in the aviation industry to address pilot mental health.

A former partner of Lubitz has shared a haunting memory of the pilot, recalling a conversation he had with her before the tragedy. She revealed to a German newspaper: "One day I will do something that will change the whole system, and then all will know my name and remember it. I never knew what he meant, but now it makes sense."

This contrasts with claims from Lubitz's family, who dispute the findings of the final report into the crash. They argue that he lost consciousness before the plane went down, rather than deliberately causing the disaster.