Originally Posted by
Lord Farringdon
All good George and seems sensible and expressed by numerous other 737 drivers in this long thread. Especially the 80 percent and 10 degrees. I mean that's just physics isn't it. On a dark night (terrain allowing) you can keep the blessed thing flying while the rest is sorted out. But one thing I wonder about. Is that power and pitch based on any given percent MAC being inside the authorised Cof G envelope? I mean, if you are unknowingly heavier than MAXTOW and with a C of G outside the envelope, in a hot and high airfield with V2 calculated to occur a little closer to the end than you would normally like, is that checklist going to help you stay airborne while you establish why your airspeed has gone to crap and the stick is shaking? Not saying that was the case in this event (especially with in daylight and CAVOK) but seriously just wondering how quick you need to decide that UAS checklist may not be your first and best port of call when the stick is shaking and your decaying airspeed is actually reliable! I suppose a wing drop like Cubana de Aviación Flight 972 might be the teller but I imagine it's all a bit late by then. An agressive pitch up immediatley after take off might also be a clue. Serious question, not trying to be smart a*** . (Ex Mil Loadmaster C130/B727).
Good questions.
I’m seeing quite a few posts of “should have done this”, “should have done that” and "I would have immediately xyz”.
When you get a stick shake during/after rotation or early in the climb out, which may or may not be associated with UAS symptoms, what are you going to do? Well, before you do anything, you need to have some idea if it is genuine or not.
How do you ascertain that? The traditional answer is performance attitudes (which we see a lot of in postings) but an aeroplane can be approaching a stall in a normal takeoff/climb attitude for many reasons, such as: strong adverse wind gradient, temperature inversion (often combined with the item before), incorrect loading, wrong flap setting, incorrect performance data and/or incorrect FMC weight/speed entries. If you leap straight into the UAS checklist at that moment, what will happen if you really *are* on the stick shake? I never tried this in the 737 sim but my gut feeling is that isn't a good place to be: on the back of the drag curve, keeping the nose high and likely take a bit of power off... Hmmm.
Remember, this is at 7,600’ASL, density altitude of nearly 9,500’ at the airport with MSAs of 14-16,000’, so close to the edge of the envelope in many respects. Some thought required before rushing into actions that may make the situation worse and that’s before MCAS rears its ugly head. Will flying the UAS pitch and power give enough of a climb gradient for terrain separation here? I can quite understand any reluctance to reduce power in this scenario, although it’s quite possible the workload was such that it didn’t get actively examined.
TL;DR If you have multiple scenarios with different required actions but similar symptoms, if you don’t do a bit of analysis first you are relying on luck...