Germanwings crash investigators review cockpit recordings found on black box | World news | The Guardian

Remi Jouty, director of the Bureau d’Enquetes et d’Analyses, holds a press conference about the Germanwings crash investigation. Photograph: Ian Langsdon/EPA

French air accident investigators say they have extracted a recording that contains “voices and sounds” from the cockpit of Germanwings flight 4U9525 that crashed on Tuesday, killing all 150 on board.

The Airbus A320 that ploughed into an Alpine mountain flew “right to the end”, the investigators said, and did not explode mid-flight. It also appeared not to have suffered a sudden drop in pressure.

The audio file was extracted from the cockpit voice recorder, one of the black boxes discovered in the wreckage of the plane, which was en route from Barcelona to Düsseldorf.

Related:Germanwings crash leaves an Alpine village shrouded in grief

The French Bureau d’Enquêtes et d’Analyses (BEA) said it was “optimistic” the second black box, the flight data recorder, would be found and the mystery of the crash solved.

“We have an audio file we can use,” Rémi Jouty, a BEA spokesperson said.

The task of the investigators in the first instance is “a job … of understanding the sounds, the alarms, the voices, to attribute the voices to different people,” he added.

“The crash zone is two hectares, which is big but not massive. We are combing the site and we will find the flight data recorder, which is built to resist a severe crash. I am confident we will find out what happened.”

Carsten Spohr, CEO of Lufthansa, the parent airline of Germanwings, said it was doing what it could to help the families of the victims, including offering flights to the crash site.

“Running an airline during such an accident is terrible,” he said at a press conference in Barcelona, adding that the Airbus 320 had been given a clean maintenance bill on Monday.

On Wednesday, grieving families of the 150 victims – mostly Spanish and German – began to arrive in Alpine villages around the crash zone.

Germanwings chief executive, Thomas Winkelmann, said that 72 Germans had died. In a statement on Wednesday afternoon, Spain’s government said 51 of the dead were Spanish.

At least three Britons are believed to be among the dead, as well as two Americans. Casualties have been confirmed from at least 16 countries overall.

Aviation experts have been puzzled as to why the plane failed to respond to calls from air traffic control and why the pilots did not send out a distress signal as the plane dropped steadily for more than eight minutes before ploughing into a mountain ravine.

Jouty said it was too early to give details of the cockpit recording. However, he said the information investigators had put together suggested the plane had not exploded and did not suffer a “classic decompression situation”.

Related:A320 is one of world's safest planes, but Germanwings crash will raise questions

Investigators refused to say more about what the cockpit recording contained.

“We have had this for a few minutes and we cannot say who is speaking. It takes time to understand these things. It’s too soon to draw conclusions about what happened,”Jouty said.

Investigators say the last recorded message from the plane came at 10.30am local time, when air traffic control at Aix-en-Provence responded to the crew’s request for permission to continue its route.

“A little while afterwards, the aircraft started a descent that it continued right up to impact just under ten minutes later,” Jouty said.

“We lost a radar signal from the aircraft extremely close to the site of impact. At which point the aircraft was at 6000 ft. The radar followed the plane to just before impact.”

He added investigators needed to explain why the plane continued to descend and did not respond to calls from air traffic control.

“We had some difficult to read it, but to our relief we have succeeded in extracting an information file, an audio file, that we can use. Now we have to work on the audio file to understand the sounds and voices that can be heard.”

Asked about the aircraft’s apparently controlled descent before it crashed, he added: “The path is compatible with the plane being controlled by pilots, except it’s hard to imagine that a pilot would send an aircraft into a mountain, and it’s compatible with an autopilot.”

He was unwilling to give any more information.

Air traffic controllers reported total radio silence from the plane as it descended before smashing into the mountain.

After postponing the search on Tuesday evening, hundreds of gendarmes, firefighters and mountain rescue teams returned at dawn on Wednesday to comb the rocky ravine in the southern Alps, between the villages of Digne-Les-Bains and Barcelonnette, where debris from flight 4U9525 is scattered.

Some had to walk three hours to reach the crash spot. Others had to be winched down from helicopters hovering over ravine that struggled to maintain their position in the wind. Rescue teams spoke of the impossibility of landing anywhere near the base of the steep escarpment.

An air investigation team from Paris has also arrived at the scene and was joined by three German colleagues.

In Seyne-les-Alpes, the picturesque alpine mountain village of 1,500 people which has been transformed into a makeshift centre of operations, support staff received the first relatives of the victims. Many families had chosen to fly to Marseille overnight and be taken by bus to the Alps to get as near as possible to the crash site and to begin grieving as they waited for relatives’ remains.

In the village, there was a mood of grief and sadness. Looking up at the mountain beyond which the plane had crashed, Maurice Borel, a retired volunteer firefighter, said: “We’re in shock, nothing of this scale has ever happened here before.”

The Seyne-les-Alpes youth centre, which would normally be packed with riotous children’s sports clubs on a Wednesday afternoon, had been made into a silent makeshift chapel and remembrance centre for the victims’ relatives.

“We just feel so powerless,” said René Dufour, a retired textile worker, as he looked out towards the snowy peaks beyond which the plane crashed. “All we can do is send all our thoughts to the families.”

The French president, François Hollande, visited the area on Wednesday afternoon with the German chancellor, Angela Merkel, and Spanish prime minister, Mariano Rajoy. At a joint press conference they pledged to do everything they could to find the cause of the crash.

The Airbus appears to have smashed into the mountain at a speed of around 700km/h (more than 430mph) violently shattering the plane into small pieces. Among the debris, investigators have the grim task of finding the remains of the 144 passengers, including two babies and 16 schoolchildren, as well as six crew.

On Wednesday, staff at Germanwings’ headquarters in Cologne held a silent tribute to the dead.

Teachers and pupils from the Joseph-König high school in the western German town of Haltern held a special assembly in memory of 16 pupils and two teachers who died in the crash while returning from an exchange trip.

Brice Robin, prosecutor for the city of Marseille, said the investigation would take weeks.

“The priority on the ground is to identify the bodies,” he told reporters after flying over the crash site.

“We owe that to the families of the victims. But it will not be done in five minutes. It is going to take a number of weeks and I think everyone should be aware that we are talking about a long time.”

Asked about the causes of the crash he said “at the moment the reasons are completely undecided”.

Earlier he told Reuters what he saw over the crash site: “We saw an aircraft that had literally been ripped apart, the bodies are in a state of destruction, there is not one intact piece of wing or fuselage.”