PPRuNe Forums - View Single Post - NTSB Recommendation re Airbus Rudder Travel Limits
Old 10th Aug 2010, 17:01
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Mad (Flt) Scientist
 
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Originally Posted by PJ2
We don't even know if the rudder pedal position "parameter" was merely derived from the rudder position, (such derivation is not unusual but is in my view a waste of time and calculating capacity), and not an independent parameter. I have been unable to locate any DFDR readings and none is provided in the NTSB report.
I agree with the use of an animation as an analytical tool; animations are great for explaining, not so great for initial understanding...

Rev the rudder parameter - footnote 84 on page 49 of the NTSB report indicates that the control positions WERE instrumented, not derived from control surface positions:

During the initial readout of the FDR, the conversion equation for the rudder pedal parameter was found to be incorrect. Thus, the FDR data had to be examined to obtain reference data to establish the proper equation for the rudder pedal position parameter. In addition, revised equations for the control wheel and control column positions were established based on the FDR data. (The airplane was not initially configured with the rudder pedal position, control wheel position, and control column position parameters because they were not mandatory when the airplane was manufactured.) American Airlines added flight control input sensors and the associated hardware to the airplane to comply with 14 CFR 121.344, which required that, no later than August 20, 2001, all transport-category airplanes be equipped with FDRs that record control input positions.
(my emphasis)

I haven't found any plots of that data yet though...
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