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[wetbehindear]

The myth of perfect automation

Machinbird thank you .

Qte

Natural Decisions. As Klein (1991) points out in naturalistic human decision making, especially that of experts, is not a formal and analytical process.
Instead it’s based on rapid situation assessesment (including the context of the situation), the serial matching of remembered patterns to the current situation and the selection of the first course of action that satisfices the need(3). Once an action is selected it is mentally simulated by the operator to determine what adverse outcomes there may be.
In naturalistic human decision making the emphasis is not upon analysis and comparison of options but upon situation assessment. Experienced operators develop a sophisticated sense of what the system is doing, and can use it to predict future states (termed expectancy) and adjust the relative salience of various cueus. In aviation this ability is known as ‘flying ahead of the aircraft’.
This expectance also allows operator’s to accept or reject data based on their internal model of the system or update and modify their model should the data call into question the validty of the model.
Automated protection decisions. The Airbus flight protection laws decision-making is quite different to the way in which human aircrew would make make such decisions.
The first stage uses a set of sampling statistics (mean and median values) and rate limiting to eliminate erroneuous data. Having eliminated erroneous inputs the second stage decision agorithm then considers a fixed set of parameter’s and initiates the protection action if required.
Epistemic vulnerability. There are a couple of philosophical problems with this approach. By using sampling statistics and filtering we are essentially removing information from the control loop.
This results in automated protection laws able to cope with aleatory uncertainty (e.g. the random distribution of noise of component failures) but vulnerable to epistemic uncertainty (e.g. events such as failures or noise that violate the assumed distribution).
The QF 72 accident is a good example of this type of system vulnerability (ATSB 2008).
In contrast a human operator directly monitoring a process would integrate the presence of noise or unexpected values into their understanding (and model) of the system and therefore this would inform their decision as to the advisability of initiating a control action.
Context vulnerability. Vulnerability is also introduced by the narrow context of data upon which the decision is made.
For example the alpha-protection law only considers angle of attack and altitude (both air data) and does not consider, for example, the presence of pilot command inputs even though the law is putatively there to prevent aircrew flying the aircraft outside the envelope.
This makes such laws vulnerable to being triggered in the wrong system context as was the case in the Iberia FL 1456 accident (4).
Expecting the unexpected. In a broader sense the Airbus protection laws are vulnerable because their sense of ‘expectancy’ is extremely weak, that is there does not exist a strong internal model of system behaviour which is used to check input values and predict future behaviour.
For example in the Airbus QF72 incident there was a persistent time history of ‘spike’ values on the ADIRU 2 channel, however this deep history was not considered in determining the validity of that input.
Rehearsal. A further limitation of the protection laws is the lack of forward projection or simulation to predict the results of the action, in the case of Iberia FL1456 the projection of the continued flightpath into impact was assuredly not considered by the automation.
Perhaps a ‘meta protection law’ should be introduced that no application of a protection law will cause the aircraft’s flight path to intersect the ground!

Uqte

I am not an expert on the matter. So I need expert view( i.e. epistemic vulnerability and context vulnerability).Can anyone quote or countermand views expressed?

If the content does not belong this thread, mods kly move this to an appropriate thread.

wetbehindear