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Old 28th Nov 2018, 13:10
  #1740 (permalink)  
bsieker
 
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Originally Posted by phil gollin
That confuses me. When the PIC transferred control to the SIC SURELY the runaway trim should have stopped as the SIC's controls would be using the input from the correct AoA sensor ?

Why did it continue ?

.
This confuses me. The 737 (all versions) has direct mechanical flight controls (hydraulically assisted). They have no provision for "using" air data of any kind, except for the strength of the artificial feel system, which depends on airspeed (measured by an independent system.)

Even in the fly-by-wire A320 the flight control computers don't really care who makes the inputs. All computers evaluate inputs from both sticks and air data from all available sensors (indirectly via the ADIRUs).

The MCAS is also completely independent of pilot inputs (except trim inputs, but that only inhibits it for 5 seconds), and no system (except possibly force sensors at the control columns themselves) "knows" which pilot is making inputs. Sometimes both do, especially in cases of a badly mis-trimmed aircraft.

Bernd
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