Originally Posted by
FullWings
Very much in agreement.
The Human Factors are, IMO, the most important/interesting part of these accidents.
To recap: There are many situations which require some sort of action from pilots, be it promptly or after consideration. The more time-critical an event is, the less time/capacity there is to figure out what to do, so responses to predictable events are based more on rules than extended cognition, hence “memory” or “recall” items are used. They need to have a simple, unambiguous trigger, e.g. an engine fails below V1, perform an RTO or GPWS says “PULL UP!”, perform the GPWS pull up manoeuvre.
When the situation is more complex and there is normally time for diagnosis, we have reference checklists which may contain decision trees, often leading to different actions and outcomes, dependent on further data. If no checklist really fits the bill completely, maybe due to multiple failures or unusual circumstances, then you need to use your general aviation understanding, backed up by specific type knowledge and all the resources you have access to in order to formulate and execute a plan of action. This is something you would generally do *after* you had determined there were no published normal or non-normal produces that were applicable, or you had applied the procedures and they had not helped or made the situation worse. Boeing specifically caution against “troubleshooting” unless all other possibilities have been exhausted but they also provide a useful “Situations Beyond the Scope of Non-Normal Checklists” guide in their training manuals.
Now, it is good aviation practice to have some kind of action associated with a single, predictable failure which affects the safe operation of the airframe, be it recall items or a reference checklist, or even just a note for crew awareness. In the case we are discussing, an AoA probe failure (which is singular, predictable and measurable) has caused a cascade of issues and warnings that are difficult to assimilate and don’t immediately point to any particular checklist, except maybe the Airspeed Unreliable one, which doesn’t include deactivating the trim. Remember we are looking at these accidents with hindsight and the warnings that occurred can be triggered by many different events that require different responses - we only know which was the correct path to take because we have most of the data in front of us to peruse at leisure.
There have been quite a few posts highlighting the startle effect plus the saturation of input channels by excess information of questionable usefulness, e.g. stick shaker, GPWS, fault messages, high control loadings, etc. It is quite easy to see how some things were missed, in fact most of the above is taught in basic HF modules but this seems have passed some manufacturers by.
It’s easy to say that you’d have disconnected the trim as soon as you got a stick shake in the climb out because the flaps are correct and power is set. Well done. But supposing that was a *real* stall warning because you put the wrong weights in the FMC so have rotated 20kts early? Not so well done now, eh? This has happened before and will happen again and is just one example of why it is so important NOT to rush to conclusions if you can absolutely help it.
Hi FullWings.
Your explanation on how things are resolved in a modern day cockpit makes for a very interesting read and should be part of the curriculum for any up and coming MCC/JOC student. It should also be interesting for the laypeople frequenting these pages. For a professional airline pilot it should be obvious.
I agree with you that Human Factors is a subject of much interest and it is also where I feel I still have the most to learn about the Ethiopean accident. As much as I hate this MAX software addition and its capabilities, I do think I have picked up on the significant features of the MCAS and further detail on it would most likely not have had any influence on how I would deal with an "MCAS Runaway Stabilizer" or whatever we end up calling this scenario.
Although some contributors on this forum have a less than diplomatic way of stating certain facts and assumptions about the crew's actions and inactions I don't think this should be interpreted as putting the whole blame on the crew. Not even close. But there certainly is a lot to be explored following the statement by Ethiopean officials that the crew "followed expected procedures" implying there are no issues whatsover concerning the crew's way of dealing with the problems of this flight. And it is in this space I believe some posters in here get a little bit agitated, trying to get that point across.
There certainly were a number of crossroads at which catastrophy could have been avoided on ET302, especially up to the point of flap retraction and a bit, and from a Human Factors perspective it is extremely interesting to learn why certain choices were made. We all know that the company culture of an airline and also the culture of countries/regions greatly influence how we behave, both as people and as pilots. This has nothing to do with the "supremancy of the Western pilot" or however some may want to phrase it in these times of identity politics.
But when countries ban unions, when people are fired for having opposing views to those of their superiors, when airlines ban handflying within the autopilot envelope and mandate autolands, when airlines have the captain always be the Pilot Flying, when one thousand airline flying hours may entail only a dozen or two actual take-offs and landings.... If you become financially penalized or limited in your career advancement due to non-compliance with said policies, you know there are issues that need to be addressed. I don't think it should be perceived as offensive to ask if any of these or other factors were important when it comes to understanding why a seemingly experienced captain would try to engage the autopilot at 400'AGL while the stickshaker is going off? And why choose the onside autopilot? Why clean up? Regardless of any NNC memory/recall items or checklists, why not establish a known and safe pitch/thrust setting and fly the aircraft? Does everything boil down to "the startle effect" when at first the stick shaker goes off and then later the AP trips off at the same time they clean up? These are not unreasonable questions to ask.
It is a sad fact that whoever is left holding the matches when the house burns down will be looked at with much scrutiny - even by his friends.