I was thinking Boeing and the FAA had been a bit slack here, but I am starting to change my mind. Clean stall, the back stick is supposed to increase all the way to the break. It doesn't in this airplane apparently because of nacelle lift. So they put a mouse in the system to drive the stab L.E. up at Vs plus a few knots to start to fly the airplane nose down so we have to pull that little bit harder. Fine. All this at low speeds - stick forces light and any runaway a non-event. Also they put it the FTM.
Now we have a situation where a dozy alpha vane sends spurious information to the mouse when hand flying it clean at say 240 knots. The airplane tends nose down in response, the pilot holds attitude in the normal fashion and trims the load out with the pickle switches. Back where we started. Five seconds later it does it again. At some stage the flying pilot or the support pilot or both are going to notice the trim wheel is running while the pilot is not trimming and follow the drill. Oppose the runaway, stop the wheel, and / or operate the stab trim cut-outs. (Is that right? - it is many years since I have been in a 737)
I don't see how it got away from them. There has to be more to it. I gather in both cases the stab trim jack has been found full scale stabilizer nose up. Unfortunately post-crash mechanical evidence is rarely relevant because everything changes during the break-up.
Be that as it may, we have two brand new, on the evidence to date perfectly flyable airplanes planted face first into the planet in broad daylight.
Either there is something the matter with the way Boeing and the FAA are doing things, or there is something the matter out here in the rest of the world. Something serious. MCL for instance raises it's hand immediately. Simulators are great training tools but you can't get hurt in one and those basic piloting defensive thought processes don't grow. The FAA is right to call for 1500 hours pre requisite for getting into an airliner cockpit. The rest of the world must follow that lead. We are going to have to toughen up. It has been made too easy. It is an airplane, not a sago pudding. It is not just a computer game, although many are selling that line. High time, I think for the regulators and operators world-wide to have a hard look at the way they are going about things.
It is them going to get the midnight phone calls.
I rather agree with you TFX, a previous LionAir crew recognised the root-cause of their problem and selected STAB TRIM CUTOFF switches to CUTOFF so the problem is far from dififcult to identify. Indeed they later took several other NNC measures that seem, on the face of it, to be rational and sensible. Thus they identified the threat, if not the cause which in this case is largely irrelevent. But what scares the crap out of me they soon selected the electric trim back on! That isn't the way of a professional crew. They soon selected it back off again, thank God, when the trim runaway re-occurred but then inexplicably
continued the flight in manual control(no a/p) and manual trim with the stick shaker running continuously! These are fundamental aberrations of simply unbelieveable proportion in an ATPL and something no normal Professional pilot would consider doing for a moment. Lion Air's crew attitude and operating standards must surely take a massive hit from these shocking errors. It isn't good enough to hide behind the company's shameful, disgraceful shoulder-sloping repetition of the wet excuse that "nowhere in these checks did they say to land at the nearest suitable airport." As if an ATPL needs to be told that! That is a disgraceful way for a company with sloppy procedures to try to shift blame onto an implied fault in Boeing's manuals and demonstrates a company culture of either blissful unawareness or wilful disregard of normal Professional procedures, airm*****ip (Oh bugger! I nearly swore again!) I mean cheesy excuses for blind unthinking magenta-line following and no apparent command presence at all.
One has to wonder whether LionAir should have been let off the EU banned list so soon...
Boeing may have made errors in their systems design but the more I read the more I see how appallingly badly LionAir crews (and maintenance?) mishandled the accident flight and those that preceeded it whilst having all the means at hand to prevent the disaster.
The Ethiopan report, should it be open and transparent, will go a long way to corroborate or refute these remarks but I'm not holding my breath on either count.