NTSB and Rudders
Stator Vane,
AA 587 was not a pilot reaction to turbulence, it was strictly the
aircraft's mechanical reaction to the rotating vortices force against the large surface area of the fin & rudder. The pilots had no effective control of the aircraft.
When you ask about the B737 events (United 585 at Colorado Springs and USAir 427 at Pitt.) here we are in a completely different situation. United encountered mountain wave turbulence which affected the flight instrument indications. The pilot reaction to an attitude transition (nose up) and erroneous flight instrument readings triggered pilot flight control inputs and the aircraft pitched over into a dive. Co-pilots exclamation, "Oh God (Flip)"! Note, she did not say Roll!
The NTSB removed the final controllers sworn statements from the official report! The controller said, "The aircraft never rolled it went straight in"!
In the USAir accident the NTSB claimed the wake turbulence from the B727 just minutes ahead had no effect on 427! They do not understand that the flight instruments can be affected! The pilot reacted to erroneous flight instrument indications! Pilots have been injstructed throughout their careers to believe their instruments and have not been told about the possibility of erroneous indications from wind shear forces in turbulence.
There never was any problems with the B737 rudder! As you know, even after they modified the rudder they continued to have problems.
The numerous reports of rudder malfunctions is, in most cases, actually aircraft wake turbulence. Dr. AA Wray of NASA affirms that in smooth air aircraft wake turbulence can persist for extended periods of time. I had a severe wake turbulence encounter 45 miles behind another 707, in smooth air!
The 'Industry' has so sensitized the pilots to this supposed rudder problem that recently a crew returned to land because the aircraft 'shuddered'!
You are correct more instruction in unusual attitude recovery is imperative. The present, Aircraft Upset Recovery Training Aid, is not only misnamed but in one reccomended procedure can almost guarranty an aircraft upset accident. It should be named Aircraft Unusual Attitude Recovery Training Aid. Once an aircraft is upset into a steep dive attitude the acceleration of G is so rapid that the possible recovery velocity is exceeded and the aircraft breaks apart in the air. e.g. NWA705, COPA 185, EgyptAir 990, etc.
The 'Industry' still insists that an aircraft will pitch down in an updraft! In my 'pitchup' in a B707, (in the clear above strong thunderstorm activity), from a weather induced updraft, the aircraft pitched up, instantaneously, to an attitude of 20-25 degrees! There was no zoom in climb just some mechanical lifting with the updraft. The aircraft's momentum carried it along, in this attitude, on its projected flight path.
Due to the vertical component of the relative wind there was no zoom in climb as you would expect in this nose attitude transition. No zoom, no increase in aircraft load factor, 'G'! No increase in G, no loss of aircraft's kinetic energy! No loss of kinetic energy no iminent stall threat! No stall threat no need for a radical pitch control input! Ease the nose down to the actual horizon, as in my case, or artificial horizon if on instruments! NOW THE BIG PROBLEM! Your flight instruments will show a rapid climb and slowing airspeed! The pilot's natural reaction will be to shove the nose down. With this radical control input and the vertical component of the relative wind, the aircraft will pitch over into a vertical dive. In the NWA 705 pitchup accident the pilot trimmed the horizontal stabilizer nose down but the aircraft did not respond as expected so he further trimmed to the nose down stop. Now he exited the updraft and normal relative wind conditions took affect and the full nose down trim pitched the aircraft over into a steep dive attitude. The aircraft came apart in the air during the attempted recovery! In the investigation both gyros exhibited severe impact damage on the nose down stops!
In turbulence the aircraft must be controlled with reference to the artificial horizon only! The erroneous flight instrument indications that trigger pilots' instinctive reactions must be shielded from the pilots' field of view! A 'heads up' presentation of the artificial horizon on the windshield?
Regards,
wsherif1