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Old 19th Mar 2019, 09:50
  #2047 (permalink)  
Rated De
 
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Similarly, outcome and assumption in piloting ability. Regulations might imply that there is ‘an average pilot’ (as I recall the wording - ‘without exceptional skill or force’), the danger is if the industry judges or classifies people in a mathematical or mechanical manner; we are not machines, computers, but variable and fallible individuals.
Thanks Safetypee.

This is relevant. At some point a subtle shift occurs; moving ever so slightly away the assumption changes, more specifically the definition shifts.
It is not noticed and to the casual observer the base assumption is unchanged. Over time, the foundation upon which the assumption was founded bears little resemblance to the original.
Subtle language shifts will give a clue, but the regulator must be looking for them.
Self regulation, regulatory capture.

The safety analysis Boeing sent to the FAA reported that the MCAS could only move the plane’s horizontal tail 0.6 degrees (out of a physical maximum of a little less than five degrees). But during later flight tests, Boeing discovered that 0.6 degrees of movement wasn’t enough to avert a high-speed stall, the Seattle Times reported. Boeing eventually increased the limit to 2.5 degrees.Despite quadrupling the amount that the MCAS could move the plane’s tail, Boeing never updated the documents it sent to the FAA. FAA engineers only found out about the change after the Lion Air crash, when Boeing sent a notice to airlines explaining how the system worked.

This encapsulates organisational deviance from normal.
Although this change is more substantial, it is often missed, so the outcome isn't adjusted either.
It is an incremental tweak here, a subtle shift there.
None of it is really nefarious, over time it isn't questioned. Call it 'assumption precession'. Small changes unnoticed do not alter the course of the event however over time the outcome will be nothing like what was envisaged. They can deliver a big shock when they are finally noticed.

“The FAA believed the airplane was designed to the 0.6 limit , and that’s what the foreign regulatory authorities thought, too,” an FAA engineer told the Times. “It makes a difference in your assessment of the hazard involved.
Bad assumption, insufficient cirtique.

Economic models are built on assumptions, like rational expectations and reasonable man.
Does Bill Gates perceive a change in say interest rates and act the same as a minimum wage worker in Chicago? Of course not but these assumptions are what underpin modern economic theory and they are in part the reason why the model fails: Bad assumptions.

Last edited by Rated De; 19th Mar 2019 at 10:30.
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