Originally Posted by
clearedtocross
This thread contains a lot of interesting and intelligent proposals to improve pilot training, aircraft system design and certification procedures. But even with all these things still further improved (which is ok of course), modern jets like all other complex systems will go on to produce odd quirks, bugs and failures. Troubleshooting by pilots and maintenance does not get easier with added complexity and some basic failures like a malfunctioning sensor get camouflaged by quadruple redundant systems, voting algorithms, Kalman filters, Fuzzy Logic, Artificial Intelligence and you name it. We all know this.
But what I cannot understand is why an airline organisation does not prevent loading poor SLF and non-pilot crew into an aircraft that had serious problems documented on the three previous flights. This without a thorough assessment of the problem(s) on ground, corrective action and then some test flights by crews prepared for dealing with such problems. That is the real killer in this instance, and not missing pilot knowhow or design/certification flaws. Airworthiness is not only about stamps and signatures on some forms. As a lowly aircraft owner and pilot I will not take along passengers for a ride if my aircraft is plagued by unresolved troubles or untested repairs of such. And I hope the airline I buy my next ticket as a passenger will not do so either. Then I will embark with confidence, be it a Boeing, Airbus, Embraer et altera.
Unlike earlier versions of B737, the 737 MAX has an extensive and powerful troubleshooting data generated in each and are available to engineers on ground. See the link below for some of the information and screen shots. This is not for the layman of course. These pages are similar to B777 on which I have trained and worked for nearly 2 decades. Each new aircraft comes with new and additional tools for engineers. A380 is far more advanced than B777 in this area. I am sure when B777X comes out in 2020 it will go further forward.
It is one thing to have these advanced systems, but if engineers troubleshoot like older aircraft, it will be hit and miss. (As you and some others have pointed out). There lies the danger.
It is too early to say what went wrong in this case other than the fact that several holes in the cheese aligned perfectly.
Though it is harsh to comment on maintenance performed with little available info, I am compelled to say that what LION air engineers did, I would have never done. This aircraft had repeated airspeed and AoA faults. The aircraft was certified by replacing one component (ADM). The nature of this defect demand engineers to test the pitot/static system with what is called an Air-data tester, which takes the instruments through full range of a flight profile and readings are compared with a calibrated source instruments. It is commonly used in all airlines and is as old as aviation. But we are not sure if Lion air used this tester, as the tech log write-up does NOT mention it, and it means they have not used it. Similarly AoA sensor has a tester. These have to be used to confirm primary instruments on which pilots depend.
The repeat nature of defects in a vital system affecting flight controls, has to treated and dealt with differently. This was a fit case for pulling the machine from service for a thorough check and probably even a test flight before releasing to line flying. Test flights are usually done by a senior pilot qualified for it and he will be trained to expect the unexpected.You can see even in this airline, some pilots managed to assess, correct and carry-on flying. But unfortunately the last one did not succeed.
Hope what I said above makes sense. Let us wait for the complete report, it is one of those intriguing accidents on a brand new aircraft, which should never have happened.
Boeing 737 MAX Onboard Maintenance Function