Post #144, Tree, Bubbers 44;
Quote:
We Boeing pilots don't have to delay reversing for a ground spoilers call because we have a handle that the PNF verifies or pulls so ground spoilers don't go through computer logic. We can reverse at touchdown. It is a nice safety feature.
I agree bubbers 44. Not being able to manually select ground spoilers with Config full is a deal breaker. Using Config 3 on short and slippery runways was to me an unsafe "workaround" due to increased speed and increased tendency to float.
My record: 10,000 + on short and slippery/icy runways in 732, about 1,000 in the 320. Caveat emptor.
It is a nice safety feature but there are also accidents which have resulted from manual selections of both systems on the 732 (reverse) and the DC8, (spoilers - more than one accident). It can be assumed that Airbus' intentions were to deal with the possibility of inadvertent deployment while ensuring their availability once the a/c was solidly on the ground and they used the technology around which the design concept was created to do so rather than defaulting to cable & pulley systems with associated mechanical interlocks.
I'm not trying to compare the two as such a discussion is profoundly pointless and a waste of time given the success of both models/types but merely trying to clarify why the design might be as it is on the Airbus.
I discussed the work-around here during the TAM accident discussion last year. The technique was discussed in terms of bringing the flap lever up one step after touchdown, (ie, Conf Full to Conf 3) to enable spoilers/brakes then reverse. Those that disagreed I don't think were aware or had not flown the 727 in which a one-step-up flap re-configuration was done routinely
after touchdown. I agree it ought not to be a work-around but a manufacturer-sanctioned and available technique for crews faced with short, contaminated runways. I agree that there may be more politics and operational or technical risk involved and that the design was a point raised in the Lufthansa Warsaw overrun accident, (Conf 3 vs Conf Full on contaminated runways). I believe that Lufthansa (and others) went to Conf 3 as a standard flap configuration for landing shortly after. Config 3 is the "recommended" flap setting but we rarely see it in the data.