Germanwings co-pilot Lubitz reset the autopilot before crashing plane

Police in Germany have removed what they say could be a 'significant clue' from his home, but did not elaborate.

Passengers with moments to live screamed in terror and the captain pounded frantically on the locked cockpit door as Lubitz, 27, wordlessly slammed the plane into the mountainside.

The shocking account of the final moments of Germanwings Flight 9525 prompted some airlines to immediately impose stricter cockpit rules and raised haunting questions about the motive of the co-pilot, whose breathing never wavered as he destroyed the plane and the lives of those on board.

“We have no idea of the reason,” Marseille prosecutor Brice Robin said, revealing the chilling conclusions reached by investigators reconstructing the final minutes of Tuesday’s flight from the plane’s “black box” voice recorder, but Lubitz’s intention was “to destroy this plane”.

German chancellor Angela Merkel, whose nation lost 75 people on the flight, said the conclusions brought the tragedy to a “new, simply incomprehensible dimension”. Devastated families of the victims visited the crash scene at Seyne-les-Alpes, looking across a windy mountain meadow towards where their loved ones died.

The Airbus was flying from Barcelona to Duesseldorf when it lost radio contact with air traffic controllers and began plunging from its cruising altitude. Eight minutes later, it slammed into the mountainside.

An analysis of transponder data by Flightradar24, a flight tracking service, showed the autopilot was reset to take the plane from 38,000 to 100 feet.

The prosecutor laid out in horrifying detail the final sounds heard in the cockpit extracted from the mangled voice recorder.

Lubitz, courteous in the first part of the trip, became “curt” when the captain began the mid-flight briefing on the planned landing, Mr Robin said.

The captain, who has not been identified, left the cockpit for an apparent bathroom break, and Lubitz took control of the jet. He suddenly started a manual descent, and the pilot started knocking on the door.

There was no response. “It was absolute silence in the cockpit,” the prosecutor said – except for the steady breathing he said indicated Lubitz was not panicked – and acted in a calm, deliberate manner.

The A320 is designed with safeguards to allow emergency entry into the cockpit if a pilot inside is unresponsive. But the override code known to the crew does not go into effect if the person inside the cockpit specifically denies entry.

Instrument alarms went off, but no distress call went out from the cockpit and the control tower’s pleas for a response went unanswered.

Just before the plane hit the mountain, passengers’ screams of terror could be heard.

“The victims realised just at the last moment,” Mr Robin said. “We can hear them screaming.”

Their families “are having a hard time believing it”, he said.

Lubitz’s family was in France but was being kept separate from the other families, Mr Robin said.

German investigators searched his apartment and his parents’ home in Montabaur, Germany, where the curtains were drawn.

The prosecutor’s account prompted quick moves toward stricter cockpit rules - and calls for more.

Airlines in Europe are not required to have two people in the cockpit at all times, unlike the standard US operating procedure, which was changed after the 9/11 attacks to require a flight attendant to take the spot of a briefly-departing pilot.

Canada and Germany’s biggest airlines, including Lufthansa and Air Berlin, as well as low-cost European carriers easyJet and Norwegian Air Shuttle announced new rules requiring two crew members to always be present.

Some experts said even two was not enough, and called for rules to require three and others questioned the wisdom of sealing off the cockpit at all.

Neither the prosecutor nor Lufthansa, the parent company of budget carrier Germanwings, indicated there was anything the pilot could have done to avoid the crash.

Before yesterday’s shock revelations emerged, Lufthansa chief executive Carsten Spohr said the airline was already “appalled” by what had happened. Later he said: “I could not have imagined that becoming even worse.

“We choose our cockpit staff very, very carefully.”

Lubitz joined Germanwings in September 2013, directly out of flight school, and had flown for 630 hours.

He underwent a regular security check on January 27, which found nothing untoward, and previous security checks in 2008 and 2010 also showed no issues, the local authority in Duesseldorf said.

Lufthansa’s chief said Lubitz started training in 2008 and there was a “several-month” gap in his training six years ago. Mr Spohr said he could not say what the reason was, but after the break “he not only passed all medical tests but also his flight training, all flying tests and checks”.

Mr Robin avoided describing the crash as a suicide. “Usually, when someone commits suicide, he is alone,” he said. “When you are responsible for 150 people at the back, I don’t necessarily call that a suicide.”

In the German town of Montabaur, acquaintances said Lubitz appeared fine when they saw him last year as he renewed his glider pilot’s licence.

“He was happy he had the job with Germanwings and he was doing well,” said Peter Ruecker a member of the glider club, who watched Lubitz learn to fly. “He gave off a good feeling.”

Mr Ruecker said he remembered Lubitz as “rather quiet but friendly” when he first appeared at the club aged 14 or 15.