airfoilmod;
FBW couldn't handle a little poly-urethane in a little hole (s). Like the B-2 that was programmed wet by ground crew and went in with a ridiculous deck angle, because electrons don't think, and when no allowance (training or disconnect) is available to the handling pilot, he's along for the very expensive and life-ending final flight. Got it?
If I may...
Clearly electrons don't "think" but neither do hydraulic fluid or cables/pulleys. The method by which control is executed is less important than the interventions available to the crew. I think most are agreed on this.
The intervention available to this crew was manual pitch through the THS Wheel on the pedestal. While we do not know yet whether the amber message, "Use Manual Pitch Trim" was actually displayed, it is whenever the airplane is in Direct Law. Regardless, the THS manual input is always available in Normal Law/Alternate Law. Clearly, the design concept behind elevator authority could not be expected to extend to 57deg NU pitch attitude. No transport category aircraft does this - the aircraft is out of control at this stage of flight and beyond test-pilot territory, from which recovery may or may not be possible.
I think had the THS wheel been aggressively moved towards ND, there is a possibility that the aircraft may have recovered but that is pure conjecture. The secondary stall may or may not have been prevented.
What is not conjecture is the behaviour of the airplane. In the circumstances and regimes this aircraft was placed in at the altitude it was, without timely and aggressive intervention, no transport category aircraft would have survived.
The suggestion that an approach-to-stall manoeuvre be carried out at low altitude, (3000ft ASL, approx), in Config FULL/gear down, with no prior briefings as to crew actions before/during/post test, indications to be expected, etc including an "in case of...", was made, contrary to the SA CAM (Single Aisle Customer Acceptance Manual) developed by Airbus for this manoeuvre/test.
The captain even indicated reluctance to execute the manoeuvre. From the Interim Report:
While the co-pilot was reading back, the Captain indicated to the New Zealand pilot that the low speed flight should be made later, during the flight towards Frankfurt. He even considered not performing it.
It is hard to say how the ELACs/SECs/FACs were responding in terms of time -the rapid changes in pitch and roll may or may not have passed the aircraft into the Abnormal Attitudes Laws due to 57deg NU pitch, followed by 42deg ND. Autotrim is not available in these regimes but manual (cable, actually), always is available to the crew. That fact is no different than any other transport category aircraft in the sense, once again, that the engineers will not consider 57deg NU, "normal flight" nor will the certification authorities require (as per earlier posts) "auto..." response from the flight controls when the aircraft itself is out of control.
From the Interim Report, regarding flight in low speed regime. My bolding:
1.17.3 Flight at low speed – FULL configuration
he flight at low speed described in the SA CAM consists of checking the activation of the angle of attack protections in normal law and FULL configuration. The flight at low speed as described in the OFC document is identical but does not include going as far as the check on the alpha max protection.
The check is supposed to be performed at about FL140. The crew must adjust the thrust in order to maintain the speed at VLS. When the speed is stable, they should place the thrust levers in the IDLE position and manage the airplane’s pitch attitude so as to obtain a rate of deceleration of one knot per second. During the deceleration, they should observe auto-trim disconnect (activation of alpha prot) then activation of the alpha floor function. This function should then be de-activated.
At a weight of 53.7 tons at the time of the check, the OFC document indicates a VLS speed of 123 knots and a minimum speed of 107 knots.
N.B.: the speeds indicated by the SA CAM document depend on the type of engines. The speed reference in the OFC document corresponds to CFM engines but the speeds indicated are in conformity with the speeds in the SA CAM manual for IAE engines. In the ISATM manual, the flight at low speed is described in more detail. It should be performed first in clean configuration and it is specifically required to compare the three AOA values before performing the flight at low speed in FULL configuration.
I do not believe any of the above was heard briefed on the CVR but we haven't heard the entire record yet.
PJ2