Originally Posted by
Musician
Yeas, but the NTSB tested the materials and found they were still exceeding design strength. The National Transportation Safety Board determines that the probable cause of this accident was the in-flight separation of the vertical stabilizer as a result of the loads beyond ultimate design that were created by the first officer’s unnecessary and excessive rudder pedal inputs. --- NASA-Langley’s and Airbus’ FEA models showed that the stress and strain profiles of the right rear lug at the time of vertical stabilizer separation were equivalent to those of the full-scale certification test at failure, and NASA’s PFA results showed that the failure load, failure mode, and location of failure initiation for the accident condition were equivalent to those of the full-scale certification test. --- The stresses developed exceeded the strength values for the CFRP material used in the manufacturing of the lugs; thus, the accident lug and the tested lugs fractured because of a tensile static overload. The accident reports has the full details on that in sections 1.16.3 and 1.16.4.
Going on memory here but I remember that the rudder travel limiter ended up being a big contributor to that accident and another close call event in AA903. In the A300 system at higher speeds, the breakout force for the rudder is high enough so that once achieved it is extremely difficult to pull back before full travel is commanded.
NTSB Recommendation re Airbus Rudder Travel Limits [Archive] - PPRuNe Forums
Of course Airbus went no no.... don't look at the man behind the curtain, look at the awful training and that FO with suspect history, and unfortunately the NTSB bought it for the final report.
I do wonder if the A380 is like the A300 in which the FDR is not recording the actual pilot inputs but the actual rudder travel.
In the AA587 data, it leaves permanent doubt since we will never really know what the FO's rudder inputs were.
Of course, even if the PF wasn't totally at fault for that goofy landing, like if the flight control system put him in a place that needed correction, I doubt that defense will mean much to EK. Just going popular opinion around here... even if he wasn't at fault at all it still wouldn't matter as it's all about public perception. I do wonder about if punitive action will be taken against the PNF as well...