Originally Posted by Rob21 Maybe this can explain why on "nice" runways (POA) is SOP (TAM) both TLs to reverse and also (maybe) there is another "SOP" selecting only one TL to reverse on the "good" engine when runway is slippery (CGH).
If you are correct, on the preceding track (CGH-CNF), the landing at Confins should have be done with both TLs to reverse, because of the runway's lenght there.
Originally Posted by PBL AI's position on (5) will be that, until the Congonhas accident, there was little evidence that failing to reduce thrust to idle on flare was an oft-repeated error. There were two incidents on record in (what AI claimed in its deposition) over 30 million fleet landings in 19 years.
Originally Posted by PBL Now we come across is a deeper reason that one cannot do what marciovp and Rob21 are suggesting. We cannot derive any meaningful *statistical* conclusion. That is: the number of total events non-X that one has registered is too small. Any Tests of Significance (I capitalise it because this is another technical term which I suggest that people look up) would show that any correlation derived from a sample of two are not significant.
It is right. You can't look at the event from a purely statistical point of view, since the kind of causality in this kind of event is not direct, but systemic. In other words, it is the well known theory of the holes and the layers, or the slices of cheese. Two three, or even ten events of this type are not by themselves statistically significant, but, if we see the things from the point of view of the relevance of the event in terms of possible consequences (or his quality), the story changes. If the runway at Taipei had been shorter and there were buildings at his end, this event could be far more tragic. After two accidents with a similar dynamic, and probably some more mistakes without consequences, it should be expected that AI at least made mandatory at that time
only one procedure with locked-out reverser, the one with both TL to idle and then both to rev, i.e. the usual and simplest one.