I cannot resist to 'paste' here the conclusion BEA extracts from its investigation on the probable causes of the accident. They are a lot, but worth to read them, in my opinion:
"Thus, the accident
resulted from the following succession of events:
□ 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;
□ Inappropriate control inputs that destabilized the flight path;
□ The lack of any link by the crew between the loss of indicated
speeds called out and the appropriate procedure;
□ The late identification by the PNF of the
deviation from the flight path and the insufficient correction applied by the
PF;
□ The crew not
identifying the approach to stall, their lack of immediate response and the
exit from the flight envelope;
□
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.
These events can be
explained by a combination of the following factors:
□ The feedback mechanisms on the part of all
those involved that made it
impossible:
-- To identify the repeated
non-application of the loss of airspeed
information procedure and to remedy
this,
--
To ensure that the risk model for crews in cruise included icing
of the
Pitot probes and its consequences;
□ The absence of any training, at high
altitude, in manual aeroplane handling and in the procedure for ”Vol avec
IAS douteuse”;
□ Task-sharing that was weakened by:
-- incomprehension of the
situation when the autopilot disconnection
occurred,
-- Poor management
of the startle effect that generated a highly charged emotional factor for the
two copilots;
--
The lack of a clear
display in the cockpit of the airspeed inconsistencies identified by the
computers;
--
The crew not taking into
account the stall warning, which could have been due to:
--
A failure to identify
the aural warning, due to low exposure time in training to stall
phenomena,
stall warnings and buffet,
--
The appearance at the
beginning of the event of transient warnings that could be
considered as
spurious,
--
The absence of any
visual information to confirm the approach-to-stall after the loss
of the limit
speeds,
--
The possible confusion
with an overspeed situation in which buffet is also
considered as a symptom,
--
Flight Director
indications that may led the crew to believe that their actions were
appropriate, even though they were not,
□ The difficulty in recognizing and
understanding the implications of a
reconfiguration in alternate law
with no angle of attack protection."
Have a nice night all. I love you.
TWRman
