PPRuNe Forums - View Single Post - Indonesian aircraft missing off Jakarta
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Old 7th Nov 2018, 11:19
  #716 (permalink)  
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Join Date: Dec 2001
Location: what U.S. calls Žold EuropeŽ
Posts: 934
Boeing warns that the stabilizer system can reach its full downward position if not counteracted by pilot trimming the aircraft and disconnecting the stabilizer trim system.
So is it time to re-introduce all the deleted posts regarding stabilizer trim and elevator efficiency and early jet aircraft design (which the 737 still is over wide areas) ?

Otherwise I am still confused about the different messeges you receive....
- "UAS", which mainly means a pitot issue
- "Faulty speed and altitude indications", which more points to a static pressure issue
and now finally
- "angle of attack sensor subject", which is a totally different system altogether

If we are confused, the pilots probably have been as well...

Now i do understand a malfunctioning AoA sensor sensing high AoA would make the red/black band come up on the speed tape (and activate the stick shaker)
But the IAS being displayed should still be correct? Which would technically not be UAS or IAS disagree at all?
Well, whether the red/black band comes up on the speed tape or the speed goes down (due to UAS), both would reduce the margin between indicated airspeed and calculated stall speed, which may then trigger the stick shaker and the nose-down auto-trim, if the algorithm is made this way...
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