One of the more interesting aspects of the NTSB’s letter is EASA’s response on pilot training (page 4).
It appears that NTSB, FAA, and EASA are agreed on the need for regulation change and the need to review aircraft for compliance (the actual applicability to individual aircraft types remains open), but apparently only EASA has considered the training issue.
The rudder design requirements are sufficient for the static and the single-input dynamic cases, but insufficient for reversals, particularly for a ‘high geared’ designs. Thus the argument for change rests on the aircraft’s susceptibility to a pilot induced oscillation, triggered by an inappropriate response to an external influence (old style human error).
The case against the A300 has been proven and apparently accepted by Airbus. For the A320 and other aircraft, the NTSB makes the strong inference of similarity, but apparently without conclusive proof.
EASA’s reconsideration of their “position on the pilot training-out as being an efficient and sufficient measure to avoid any new hazardous situation … ” and “that crew use of rudder pedal inputs in upset encounters cannot be ‘trained out’ ” points towards a system change as being the only viable solution for a range of aircraft.
Essentially EASA has changed its view of the pilot’s contribution towards safety in situations involving aircraft with deficient systems, where the pilot through erroneous behaviour, contributes to an accident. This is a major advancement in safety thinking, but could have very wide ranging implications.
Consider the MD-80 take-off configuration warning system. A recent accident involved pilot erroneous behaviour and a weak system (modern regulations already require a more reliable configuration warning system). Arguably problems of configuration warning failure have caused more accidents than the rudder problem in turbulence encounters, thus these systems should also be considered as unacceptable.
This line of thought (the change in the assumed capability of the pilot), could question many other aspects of weak designs which continue in service due to ‘grandfather rights’, or even industry lobbying, e.g. contaminated runway operations FAR vs CS 25.
The next move by the regulatory authorities could be interesting, particularly the FAA who appear to ‘believe’ in training as a solution for many safety aspects.