On the screen, facing a silent courtroom, an A330 plane flies between the sky and the ocean.
At the Rio-Paris trial, experts retraced on Wednesday October 12 the four and a half minutes that led to the crash on June 1, 2009. On the third day of the trial for involuntary homicides of Airbus and Air France, four members of the first college of experts, appointed during the long investigation which followed the disaster, detailed their work.
After the discovery of the black boxes two years after the crash at 3900 meters at the bottom of the Atlantic, they were tasked with exploiting the two components, namely the "
Flight Data Recorder
" (FDR) which keeps the flight parameters and the “
Cockpit voice recorder
” (CVR) which records voices and noises from the cockpit.
Before the possible broadcast of the CVR soundtrack, requested by the families of the victims and which will be decided on Thursday morning, the experts described to the Paris Criminal Court the last minutes of flight AF447.
Read alsoCrash of the Rio-Paris flight: Air France and Airbus in court
228 people on board
On the evening of May 31, 2009, the plane took off from Rio de Janeiro with 228 people on board and the flight went normally at first, summarizes one of the expert at the helm, relying on a map, charts and diagrams.
The A330 is entering the Intertropical Front (ITF), a dangerous weather zone at this time of year, characterized by large cumulonimbus clouds as well as thunderstorms and violent showers.
The plane was in the hands of the two co-pilots, the captain having gone to rest when, at 2:10 am in universal time, three short rings signaled that the autopilot was disengaging.
Following the “
procedure
”, one of the co-pilots declares “
I have the controls
” and takes the hand, describes the expert who specifies that, over a period of ten seconds, “
six alarms will follow one another
”.
Read alsoRio-Paris crash: the Paris prosecutor's office appeals the general dismissal
The pilots quickly realize that they have “
lost gears
”: the indications they receive in this regard are erroneous.
The altitude is also suddenly about 400 feet (122 meters) lower than the 10,700 meters previously displayed.
"
This does not correspond to reality
", specifies the expert: "
It is an effect of the freezing of the
Pitot probes which, obstructed by ice crystals, will stop working for less than a minute.
In response, the co-pilot caused the aircraft to pitch up, which began to climb and oscillate to the sides.
The stall alarm sounds, a synthetic male voice that repeats “
Stall
”.
"
It's a first element of surprise that will destabilize the crew
", specifies the witness.
"Incomprehension"
The note “
do
” sounds next: this is the altitude deviation alarm, which sounded before because of the false altitude loss and which sounds again.
This time, it is on the contrary because of a “
higher altitude
” than normal, because the plane, pitched up, climbs.
In the middle of the night, "
one can imagine that the pilot does not necessarily perceive
" this difference, underlines the expert.
Read the fileThe tragedy of flight AF 447 and its consequences
Soon, the “
Stall
” alarm starts ringing again, for 54 seconds.
And the plane, after reaching an altitude of 11,600 meters, no longer has lift: it begins to stall.
"
We have a choppy piloting
", "
totally disordered
", comments the expert.
Disoriented, the navigator has “
doubt about the effectiveness of the controls
”.
Called back by his colleagues, the Captain then returned to the cockpit.
“
We lose control of the plane
,” they tell him.
The device "
is falling at 14,600 feet (4.5 km) per minute, it's considerable
", comments the expert.
"
During the following two minutes until the impact, it is the incomprehension which dominates, the situation is confused
".
As the ground proximity alarm sounds, they attempt to pull the plane up.
"
Until the end, there is a dialogue that takes place in the crew, which seeks to find out what is happening to it
," said the expert.
The plane hit the sea at 300 km/h, almost horizontal.
After their explanations, the experts broadcast a digital reconstruction.
For 4:30 minutes, total silence filled the courtroom.
During the rest of the hearing, differences emerged between one of the experts and the other three on certain aspects of the report.
Its conclusions nevertheless clearly question the role of Air France and Airbus with regard to the icing of the Pitot probes.
Questions are to be put to them on Thursday.
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