Well, the same question that arises on a half-dozen other threads seems to have chosen different venues for its emergence. A bit like thunderstorm cells, isn't it? One matures and dies within a fraction of an hour but the squall line persists. This thread seems to have died over people's positions on the Cali accident.
Let's see if we can resurrect the discussion.
Terpster wants to prioritise the crew's violation of the good arrival/approach practice, as laid down in the design assumptions for the arrival/approach (say, similar to TERPS). RAT and bubbers want more or less to join that view.
I argue for consideration of all the factors, and consider that view proposed also by fdr, SR71, and Dozy.
Even though we were arguing, these views are not necessarily in contradiction.
Alf pointed out that, besides the comprehensive analysis (which he termed "academic" - surely he knows better than that!), there is a need to provide guidance to the front-seaters. My view on that: yes.
I pointed out that there is a trope:
Originally Posted by PBL
(a) there was a failure of airmanship; (b) other stuff is secondary; (c) failure of airmanship is thus "root cause".
"Airmanship", or "adherence to TERPS-like approach procedures", or what-have-you. There was a failure of two organs sitting behind the eyes in the front seat; we have agreed. That failure was, as I have argued, facilitated in a way that those who have not experienced suchlike will not necessarily readily understand.
Let me offer an extreme example. Suppose it is well known that, at one specific crossing in the middle of town, the traffic lights show red for "go" and green for "stop". Everybody knows it. They know to take it into account. Nevertheless, would we be surprised if more accidents take place at that intersection than elsewhere in town? I would suggest: we would not be surprised.
Now, suppose we look at causes. We have a specific accident in mind. Mr. Jones went through a green light and collide with Mrs. Smith. One might argue: (i) Jones knows about the light and the convention; (ii) he willfully went through a green light without sufficient care and attention; (iii) he hit Smith's car; (iv) his insurance pays. One might also argue (I) as (i) above; (II) the city council knows about the light, that this is a counterintuitive affordance (in Don Norman's use of the word), and the result of counterintuitive affordances, namely that people are induced to do the "wrong" thing, even though they might theoretically "know better"; (III) the council's insurance pays.
There are two issues here. One is causality, the other is responsibility (phrased here as responsibility for compensation, as it often is in real life). I have tried previously to separate the two, with limited success. Let me point out here that in terms of causality we cannot ignore any of (i), (ii), (iii) or (II). Ideally, AngloSaxon common law (for example) suggests in general that responsibility follows causality, but in practice (that is, in the actual legal environments of countries following this paradigm) other factors mitigate.
Automation provides affordances in Norman's sense, lots and lots of them, for example behavior of nav data bases in unanalysed situations (two navaids within reception range with identical ID and FREQ). And so do variant design of approach procedures (naming an approach after an end point, for example). Causal analysts cannot ignore those, as I have tried to argue.
There is a criterion that will prioritise crew behavior over other causal factors, as terpster, RAT and bubbers wish to do, namely that other factors, such as DB design, FMS design, approach design, are temporally prior to the playing-out of the accident event, and the behavior of the participants during that playing-out should be prioritised over the temporally-prior factors. The reason for this causal priority can be seen to lie in the phenomenonen that the participants are expected to avail themselves of free choice, and choices are available to them whose consequences are not the accident scenario. Furthermore, those choices (which they unfortunately did not make) are worth making for more than the reason that they would have avoided *this specific* accident.
Examples of these choices are: (A) follow the full approach procedure diligently, including the arrival; (B) don't descend below MSA unless following the arrival/approach diligently; (c) in the sim, practice cleaning up the airplane upon GPWS warning.
Difficulties with the application of this criterion are that, although the design of the DB/FMS/airplane automation in general temporally precedes the playing-out of the accident event, that design is a design for certain specific future behavior, and that future (at design time) behavior is part of the behavior during the playing-out of the accident event. Forethought is explicitly required of the designers: possible future behavior must be analysed and hazards avoided or mitigated.
Similarly, crew behavior, with its MttB characteristics, is heavily mediated by the flying environment in which they have operated (which is the basis for terpster's 1996 critique of the US regulators, which he reprinted here).
So in fact it is not so easy to discriminate on the basis of the temporal situation of factors. Because we look with different-colored glasses. For the crew, we look at behavior-at-the-time and fail to look so closely at what in the past has afforded their current behavior (rose-colored glasses). For the kit designers, we look at the decisions they made in advance, and not so much at the behavior-at-the-time of the kit (lilac-colored glasses). There are other participants, past and present: controller, approach designers, navaid-placement designers, etc - let me stop for the moment with rose- and lilac-colored.
I propose we should look with clear-colored glasses. This is where I think there is lots of material to continue the discussion. For I don't think this is all about a few variously-experienced people blabbering in their free time on an internet forum. I think it is a major research topic for those interested in reducing complex-system accidents in general and commercial-aviation accidents in particular. SR71's citation of Kathy Abbott's view is pertinent.
PBL