Bearfoil
the initial pitch up is a direct response to the thrust application, and achieves a rapid pitchup rate being developed. During the pitchup, the pilot inputs full AND SSC elevator input, but the pitch couple of the thrust line defeats the available elevator authority in the full ANU stabiliser position which has been achieved due to the continued trimming during the deceleration which has occurred due to the underlying fault of the AOA probes being frozen from water ingestion through the seals. The aircraft (IIRC... haven't looked at the data for about 12 months...) exhibits lateral instability during this due to aerodynamic stall, coupled in part with the plots lateral control inputs (the system is not designed to be operating in this regime... and this area was the most interesting to assess if the aircraft fully complies with CS25 stability requirements, it being evident from a number of cases that the FBW aircraft can end up in aerodynamic stall contrary to the design specifications of envelope protection. A conventional control aircraft is required to achieve particular lateral stability and control requirements in a stall, whereas the certification of a FBW aircraft that "avoids" stall has alternative compliance criteria....)
The aircraft pitches up due to the out of trim condition and achieves a very low speed, high pitch attitude, but at a moderate AOA, until it finally runs out of energy and starts to fall off with both roll and pitch excursions, with initially increasing AOA. The ensuing flightpath increases CAS, and results in an increase in AOA again, leading to secondary stall... pitch attitude lowers and the aircraft enters a final dive.... with increasing CAS and increasing AOA again...
To regain control the crew needed to reduce the pitch up couple ie reduce thrust, or trim the stab forward from it's extreme ANU position (11u?... memory fading...), and lower the pitch attitude, possibly by rolling off. Ailerons are low effectiveness (and the data showed possible roll reversal IIRC... which is not too good for a CS25 certified aircraft...
), and judicious use of rudder sounds nice but is rather nasty in a swept wing jet transport (do not take the simulators behaviour in training as being representative of the control derivative in the stall regime... data from various events show that the aircraft can achieve very high roll rates ie 5-6 times higher than normal control authority when in a stalled condition). Judicious may be a great term in a subsequent inquiry but it is hardly precise in a high oscillatory loading, dynamic upset event. refer FAR25 CS25, and AC25.7A.
Power reduction at low altitude in a low speed condition is not going to be foremost in a pilots mind... and the rapidly deteriorating flightpath (which additionally result in g loads in the cockpit that are not simulated in any FFS) results in a high cognitive workload, and a likely massive spike in stress levels in the crew. The oversight of the trim state is not a surprise, and has been evidenced on numerous occasions on various types, (the A310 being over represented, as well as the A300-600...)
Humans are a bit like democracy, a lousy program, but far better than all the alternatives... The crew didn't go out planning to have a bad day, but the circumstances they were placed in technically coupled with their unfortunate ad-hoc attempt to achieve a desired "mission" goal placed them in a rapidly deteriorating situation where the time line, workload and stress resulted in their being unable to recover the SA that they had lost in the commencement of the procedure.
Any perception that aviation is a simple task fails to understand the facts of the physics of flight. The routine nature of RPT makes it easy to underestimate the underlying demands of operating high energy machinery in varying environmental conditions with varying levels of system serviceability.
Would think it appropriate for AI to add a CWS voice command such as: "MANUAL STABTRIM REQUIRED" or similar for degradation to direct law, instead of the fairly anemic ECAM messages which were patently not cognitively effective on the day.
RIP.
FDR