The BEA releases the “Final report” on Air France Flight 447

The BEA report (pp 200-201) concluded:

• The crew possessed the licenses and ratings required to undertake the flight.
• The aeroplane possessed a valid Certificate of Airworthiness, and had been
  maintained in accordance with the regulations.
• The aeroplane’s weight and balance were within operational limits.
• The aeroplane had taken off from Rio de Janeiro without any known technical
  problems, except on one of the three radio management panels.
• The composition of the crew was in accordance with the operator’s procedures.
• The meteorological situation was not exceptional for the month of June in the
  inter-tropical convergence zone.
• There were powerful cumulonimbus clusters on the route of AF 447. Some of
  them could have been the centre of some notable turbulence.
• An additional meteorological analysis showed the presence of strong
  condensation towards AF 447’s flight level, probably associated with convection
  phenomena.
• The precise composition of the cloud masses above 30,000 feet is little known,
  in particular with regard to the super-cooled water/ice crystal divide, especially
  with regard to the size of the latter.
• Several aeroplanes that were flying before and after AF 447, at about the same
  altitude, altered their routes in order to avoid cloud masses.
• The crew had identified some returns on the weather radar and made a heading
  change of 12° to the left of their route.
• At the time of the autopilot disconnection, the Captain was taking a rest.
• The departure of the Captain was done without leaving any specific instructions
  for crossing the ITCZ.
• There was an implicit designation of a pilot as relief Captain.
• There was an inconsistency between the speeds measured, likely following the
  blockage of the Pitot probes by ice crystals.
• The AP then the A/THR disconnected while the aeroplane was flying at the upper
  limit of a slightly turbulent cloud layer.
• The aeroplane systems detected an inconsistency in the measured airspeeds. The
  flight control law was reconfigured to alternate 2B.
• No failure message on the ECAM clearly indicates the detection by the system of
  an inconsistency in measured airspeeds.
• The pilots detected an anomaly through the autopilot disconnection warning
  that surprised them.
• The engines functioned normally and always responded to the crew’s inputs.
• The PNF called out imprecise flight path corrections. They were however essential
  and sufficient for short-term management of the situation.
• The last recorded values were a pitch attitude of 16.2 degrees nose-up, roll of
  5.3#degrees to the left and a vertical speed of -10,912 ft/min.
• The Pitot probes installed on F-GZCP met requirements that were stricter than
  the certification standards.
• Analysis of the events related to the loss of airspeed indications had led Airbus
  and Air France to replace C16195AA Pitot probes by the C16195BA model. The
  first aeroplane had been modified on 30 May#2009.
• EASA had analyzed Pitot probe icing events; it had confirmed the severity of the
  failure and had decided not to make the probe change mandatory.
• The flight was not transferred between the Brazilian and Senegalese control
  centres.
• Between 8 h 22 and 9 h 09, the first emergency alert messages were sent by the
  Madrid and Brest control centres.
• The crew was not able to use the ADS-C and CPDLC functions with DAKAR Oceanic.
  If the connection had been established, the loss of altitude would have generated
  an alert on the controller’s screen.
• The first floating aeroplane parts were found 5 days after the accident.
• The flight recorders were recovered 23 months after the accident.

The accident occurred after the following events:

1. Temporary inconsistency between the airspeed measurements, likely following
   the obstruction of the Pitot probes by ice crystals that, in particular, caused the
   autopilot disconnection and the reconfiguration to alternate law;
2. Inappropriate control inputs that destabilized the flight path;
3. The lack of any link by the crew between the loss of indicated speeds called out
   and the appropriate procedure;
4. The late identification by the PNF of the deviation from the flight path and the
   insufficient correction applied by the PF;
5. The crew not identifying the approach to stall, their lack of immediate response
   and the exit from the flight envelope;
6. The crew’s failure to diagnose the stall situation and consequently a lack of inputs
   that would have made it possible to recover from it.

Download the complete final report here:

BEA FINAL REPORT on AF 447