I did follow that earlier discussion, PBL.
Originally Posted by PBL
Note, for example, that had the runway been, say, 3km long, there would have been no overrun. That means that the relatively short length of the runway was a causal factor in the accident. You need therefore to tell me why and how you prioritise not reducing thrust (as a factor) over the length of the runway (as a factor).
With respect, PBL, I did tell you how I prioritise not reducing thrust, by referring to it as the 'primary cause.' By definition, there can only be ONE primary cause.
Sure, the shortness of the runway, the lack of a runoff area, the surface, the weather, possible delay in applying manual braking etc. all contributed to the severity of this accident. They may even have been responsible for making it a catastrophic 'accident' instead of a mere 'incident.' But they are not the features of it which deserve the most urgent attention, from the point of view of avoiding any recurrences.
One of the problems with all crash investigations is that the resources allocated to them, and the notice taken of any findings, tend to be proportionate to the number of people killed. The fact that pilots were capable of making this mistake, and appropriate action which could have been taken to avoid it happening in the future, was very clearly spelled out by the Taiwanese Aviation Safety Authority in their very competent report on the 'carbon copy' 2004 Transasia A320 'no injuries incident' at Taipei. To quote their report:-
"According to the documents provided by the aircraft manufacturer, the reason of “RETARD” stop was caused that the thrust control lever no.1 was at reverse position. When the FWC detected an internal signal of TLA inhibition which includes either thrust control lever at REV position and then FWC stopped the aural “RETARD” alert.
"During landing, the FWC has delivered four aural “RETARD” alerts and then after touchdown two seconds it came to stop. But at this moment the thrust control lever no.2 was not pulled back to idle or reverser position yet. In this situation, one of thrust control lever is not in proper position but the aural “RETARD” alert already stopped. The aural “RETARD” alert should continue or there should be other ways to remind the pilots of pulling back thrust control lever to reduce the probability of an accident caused by human error."
They included a recommendation on this aspect in their Safety Recommendations and the Report records Airbus' response:-
"According to the Airbus Company
"1. In response to: Reviewing the design of stop mode of Retard warning sounds or accommodating other warning methods to ensure that the warning will continue before the thrust levers are pulled back to Idle notch after a touchdown has affirmed.
"Airbus Company Response:
"Airbus has developed a specific warning when one throttle is set to reverse while the other is above idle. This warning generates an ECAM warning "ENG x THR LEVER ABV IDLE", a continuous repetitive chime (CRC), and lights the red master warning light. This new warning is implemented in the FWC standard "H2F3".
"A Service bulletin will be issued very soon on this subject."
http://www.asc.gov.tw/acd_files/189-c1contupload.pdf
I gather that the modification has been offered to airlines as an option but has not been taken up much so far (if at all). It bothers me, too, that as far as I know Airbus are not even incorporating it in new construction.
With hindsight, if Airbus had 'pushed' the available mod. more - or, ideally, if the relevant authorities had made it the subject of an Airworthiness Directive - the Congonhas crash could have been avoided; or at least had much less severe consequences.
I hope that makes my tendency to concentrate on the 'primary cause' a little more understandable? As things stand, the same sort of accident could happen again tomorrow.