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Old 17th Dec 2013, 16:47
  #67 (permalink)  
gonebutnotforgotten
 
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(re AF incident at Tel Aviv) There's more to it than just dumb use of A/Thr

Yes, not nice, but I thought the most interesting bit in the report might be this (end of para 3.4):
Lors de ce dernier virage, la PF a donné un ordre à cabrer pendant dix secondes en contradiction avec les ordres des FD. Le facteur de charge a augmenté ainsi que la vitesse du seuil de la protection ALPHA FLOOR. La vitesse a chuté en dessous de VLS jusqu’au déclenchement de la protection ALPHA FLOOR.
Les pilotes indiquent qu’ils pensaient que l’A/THR ajusterait la poussée pour maintenir la vitesse. L’action à cabrer de la PF sans intervention du PNF montre que l’équipage n’a pas identifié les risques associés au non-suivi des FD en mode OPEN DESCENT
Which roughly translates to:
During the final turn, the PF applied a pitch up command for 10 seconds, opposite to the FD indications, The g increased as well as the Alpha Floor Threshold speed. The speed fell below VLS until Alpha Floor Protection was triggered.
The pilots said that they thought that the A/THR would adjust thrust to maintain speed. The pitch up command from the PF, without intervention from the PNF, showed that the crew did not identify the risks associated with not following the FD in OPEN DESCENT.
I would go further, the rearward heave on the side stick showed that the PF simply hadn't a clue about how the C* control law worked in pitch, and that she thought she was still flying a conventional aircraft aircraft like a 737. She ALSO didn't understand the concept of thrust versus speed modes of the A/THR, but it is hard to know which is more egregious.

Later on the report says:
L’enquête a montré une méconnaissance du fonctionnement de l’A/THR et de l’importance du suivi des FD en mode OPEN DESCENT. La même incompréhension des automatismes se retrouve dans l’événement survenu cinq jours plus tard sur le F-GKXO.
The investigation has shown a lack of knowledge of the A/THR function and the importance of following the FD in OPEN DESCENT. The same lack of understanding is seen in another event 5 days later on [another aircraft].
With respect, it shows a lot more, just as the investigation into AF447 showed a lack of knowledge that went far beyond the stall warning system, basic instrument flying for a start. But the world, FAA, EASA, ICATEE et al, is reacting to the bits the BEA noticed, not the ones they missed.

Last edited by gonebutnotforgotten; 17th Dec 2013 at 22:26. Reason: To clarify the subject after mods moved the thread to this one
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