Flight 4U 9525: What happened in the final 30 minutes
Richard Westcott on what we know from the cockpit voice recorder
French accident investigators have released a preliminary report into the downing of the Germanwings flight 4U 9525 in March 2015.
Their evidence, obtained from the cockpit voice recorder and other "initial information" outlines in more detail how co-pilot 28-year-old Andreas Lubitz brought down the Airbus.
So how did this final half hour unfold?
Germanwings flight 4U 9525 took off from Barcelona Airport heading for Duesseldorf, with 150 people on board, at 09:01 GMT on 24 March.
The Airbus 320 began travelling over the sea towards France, taking about half an hour to climb to 38,000ft (11,600m).
It should have been a two-hour flight and, in the first 20 minutes of the flight, the pilots can be heard discussing the stop-over at Barcelona with a flight attendant.
At 09:30 the plane made its final contact with air traffic control - a routine message about permission to continue on its route. Everything seemed to be going as planned.
Shortly afterwards, the captain told the co-pilot he was leaving the cockpit and asked him to take over radio communications. The cockpit door is heard opening and closing.
Seconds later, shortly before 09:31, the selected altitude is changed from 38,000 ft to 100 ft and the plane begins its descent.
At 09:33, air traffic control contacts the co-pilot - and continues to do so over the coming minutes - but receives no answer.
A buzzer requesting access to the cockpit is heard at 09:34. Knocking and muffled voices asking for the door to be opened are heard until the end of the recording.
At 09:39, "noises similar to violent blows on the cockpit door were recorded on five occasions" over the course of a minute.
The "Terrain, Terrain, Pull Up, Pull up" warning is triggered at 09:40: 41 and continues until the end of the recording at 09:41:06.
French prosecutor Brice Robin gave details of events on board the Airbus when he briefed journalists after the cockpit voice recorder was analysed in the days after the crash.
He said that during the first 20 minutes of the flight, the co-pilot's responses were courteous, but he become "curt" when the captain began the mid-flight briefing on the planned landing.
It was shortly after this that the captain left the cockpit, probably to go to the toilet, and within seconds Lubitz had altered the flight monitoring system to send the aircraft into descent.
"This action on the altitude controls can only be deliberate," said Mr Robin.
- 1. 09:30 - The plane makes final contact with air traffic control
- 2. 9:30:55 - Autopilot is manually changed from 38,000ft to 100ft
- 3. 9:31 - The aircraft begins its descent above the French coast
- 4. From 09:33 - Air traffic controllers try to contact the pilots, with no response
- 5. 09:40:47 - Last radar position of the plane registered at 6,175ft, just 2,000ft above ground
- 6 09:41:06 - Cockpit recording ends at the moment of collision
In the 10 minutes it took for the plane to plummet through the sky, Lubitz did not say a word and his breathing remained normal - despite repeated attempts by crew members and air traffic control to get him to respond.
The Airbus descended at a rate of about 3-4,000ft per minute. The last radar contact was at 09.40:47 GMT at 6,175ft.
During the very last moment of the recording passengers can be heard screaming. Mr Robin said he believed they were unaware of what was happening in the cockpit up until this point.
The plane hit the mountain at 700km (430mph) an hour. "Death was instant," he added.
Co-pilot 'wanted to destroy plane'