Outstanding discussion, especially from ELAC, Bernd, ChristiaanJ, Flight Safety et al. I'm sure we have all learned a huge amount about both the accident itself and the workings of the A320 (auto) thrust system. The whole 100+ pages should be compulsory reading for all Airbus pilots. Danny, the whole reason for having Pprune in the first place is eloquently proved by the contributions of the above gentlemen - thank you all.
If one discounts the possibility of a fault in the thrust/thrust lever system (I'm not discounting the possibility but it is a long shot), then the investigation must centre on the "WHYs."
Why did the PF leave the lever in the climb detent?
Why was his mind set in that direction?
What was it about the system that had him thinking in that way?
Why did Airbus design it that way?
Having flown both Airbus and Boeing types in the past 5 years including the 320, I am convinced that the non-moving thrust levers are not a good idea. Someone asked a long way back why it is that Airbus designed the system this way. I seem to remember that one of their sales brochures mentioned that it was simpler (no back-drive mechanism to go wrong), thus lighter and of course cheaper but I cannot find the reference now.
Having also watched many pilots new to this system, operate the aircraft very poorly in both sim and aircraft, with little or no idea of what actual thrust the system was giving them, I am convinced that the design is inherently faulty. The essential cues of a moving lever are missing from the pilot's sensory system particularly in the most critical areas - approach and landing.
I've lost count of the number of times I've covered the EPR/N1 gauges and asked the other pilot what his power setting was, only to discover he had absolutely no idea. The system sucks you into believing that it will always look after you.
The tactile, aural and visual cues given by the thrust lever position cannot be over-emphasised, in my opinion. Having read the whole thread from day one, I find it very difficult to believe that this is not seriously implicated in whatever thinking led to the No 2 being most probably left in the CLB position. This is not anti-Airbus - one has to remember merely the ridiculous config/cabin altitude warning horn on the 737 to see that bad design affects both manufacturers - but it surely is an area that must be looked at in a critical manner after a number of such incidents/accidents. If not, I fear we will be discussing a similar accident in a few years time. The confusion that reigned on the TAM flight deck after touchdown should not be possible on any modern airliner. Unfortunately, such mode/situational confusion is common on many types. Professional pilots and the travelling public deserve better. Airbus and Boeing please do not forget the fallible humans at the front end and design man/machine interfaces that take full account of our human frailties. Your machines are technically excellent in most areas and rarely fail catastrophically. Can the same be said for the humans?
SID
ps It is also worth bearing in mind that Airbus and Boeing are not above using forums such as this for their own purposes, especially after an accident such as this. Major corporations don't have morals or scruples - only 'interests'.
Last edited by SIDSTAR; 9th Sep 2007 at 07:38.
Reason: for clarification