Various experts at American Airlines told the Board that they had always believed that VA provided absolute structural protection. American had, furthermore, incorporated into its "Advanced Aircraft Maneuvering Program," which was intended to teach pilots how to recover from upsets and unusual attitudes, the advice that rudder rather than ailerons/spoilers should be used in certain circumstances, together with the implication that unusual attitudes were most likely to occur as a result of wake encounters; but there was no guidance on the possible effects of rapid rudder reversals. Evidence existed that this program had had an influence on the accident's first officer's flying technique. Another document, the Airplane Upset Recovery Training Aid, prepared cooperatively by airframe manufacturers and a number of airlines, had also emphasized the use of rudder in unusual-attitude recoveries. Airbus had criticized it, not on structural grounds, however, but because unwary use of the rudder could lead to spins. Incidentally, Airbus also expressed doubts about the realism of simulators-another issue that would later play a part in this accident investigation.