Originally Posted by
Rainboe
Well the guy doing the simulator replication used large amounts, not 1.2". I'm inclined to believe what the simulator did, not what the FAA report stated, as all jets I know of work pretty similar. I do not believe the A300 uses 1.2" rudder pedal deflection to produce large rudder response at low climb speed. If the report insinuates this, it is written wrongly. That AA pilot on film was using large foot movements. Small or large anyway, there is no argument- the fin came off through overstressing because of large rudder deflections, not through any defect and not because it collected water. The only productive discussion is why was this technique used and are the implications of it understood by those who professed at the time to not understand the hazards involved. If anybody is still in doubt about the point, they should stop passenger flying forthwith until they are trained up.
Well first, it wasn't an "FAA report," it was an NTSB report - second, the simulator is going to do whatever it is programmed to do - nothing more ... nothing less. With proper programming you can make any simulator fly just like the space shuttle. And as you should know, the FAA evaluates simulators to make sure they perform and handle as much like the airplane as can be determined. The data they use for comparison purposes is data gathered during flight testing of the airplane. If you were watching someone in the simulator flailing around on the rudder and the pedal deflections were more than the 1.2 inches described, then I can promise you the airspeed was significantly less than 250 knots and I can promise you that the deflection was more on the order of 4 inches than it was 6 inches. (Sometimes pilots have a problem discerning the difference between those measurements, but that's a debate for another forum!)
No one has said that "the A300 uses 1.2 inches of rudder pedal deflection to produce large rudder response at low climb speed." The accident report specifically describes maximum rudder pedal deflection at 135 KCAS (note-calibrated airspeed) as being 4 inches using 65 pounds of force, and at that maximum pedal deflection, the rudder should be deflected 30 degrees. The same chart (and I'm referring to the chart on page 23 of the report - but, the chart on page 27, cited by
RatherbeFlying, is quite eye popping in the relationships it shows!) describes maximum rudder pedal deflection at 250 KCAS as being 1.2 inches using 32 pounds of force (there is a note, stating that this 1.2 inches
may change slightly because of the response of the yaw damper), and at that maximum rudder pedal deflection, the rudder should be deflected 9.3 degrees.
So the comparison between the A300-600 and the B-767 (similar sized airplanes) goes like this (same info as supplied by
RatherbeFlying, but perhaps a little easier to read:
At 135 knots:
A300-600
breakout force = 22.0 pounds
pedal force at maximum deflection = 65 pounds
pedal travel at maximum deflection = 4.0 inches
rudder deflection at this point = 30.0 degrees
B-767
breakout force = 17.0 pounds
pedal force at maximum deflection = 80 pounds
pedal travel at maximum deflection = 3.6 inches
rudder deflection at this point = 26.0 degrees
At 250 knots
A300-600
pedal force at maximum deflection = 32 pounds
pedal travel at maximum deflection = 1.2 inches
rudder deflection at this point = 9.3 degrees
B-767
pedal force at maximum deflection = 80 pounds
pedal travel at maximum deflection = 3.6 inches
rudder deflection at this point = 8.0 degrees