Thread: 737 MAX future
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Old 11th May 2019, 07:43
  #55 (permalink)  
Bend alot
Join Date: Oct 2017
Location: Tent
Posts: 364
Originally Posted by wiedehopf View Post
If it failed on 737 NG or Classic then you might have had continuous stick shaker which means you lose stall warning because it's already going off and no longer reliable.

That's not the "certified" state either and you haven't expressed concerns about it.
Having a third AoA sensor to fail functional with one failure is a feature the regulator could require from all transport aircraft built after date XYZ.
Would that improve safety? Maybe.

Still arguing that it's a non certified state is bogus.
When a system fails, some degradation can be declared acceptable.
The aircraft is certified if an AoA fails the stick shaker goes off, possible a requirement to get certification - the aircraft still operates the same regardless of where you are in the envelope.

The difference is in the MAX you get more than the stick shaker with an AoA failure you get a change of aircraft characteristics in certain areas. That change is "unknown in quantity" close to a stall and that change is known to be outside certifiable limits.

I expect it is very easy to get certification with a MCAS U/S, but I very much doubt it can be done without detailed training best done in the simulator - so there is a reduced startle factor with less experienced pilots.

Keep in mind where MCAS is actually required is in a small window of variable conditions and to NEED to be there, it is probably not a walk in the park day. So best not to have more surprises and start learning along the way when workload is already high.

Example - above 1,000 ft flaps up AP on - Birds! pull up, AP disengages miss birds, Another flock of birds again pull up in MCAS area now and it trims. You then trim to level as birds seem gone (MCAS deactivated) yet another flock of birds - pull back, this time the coulomb just comes right back aft into your crouch just like a cable has broken. Startle factor for more than a fraction of a second and it is in a stall, at best a few thousand feet AGL.

So you have just done two avoidance's in a B737, then third was in a fighter jet. Best to have some fighter jet training if that is what can happen.
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