Maneuvering airspeed for Airliners
I was reading an article on an airliner crash in the May 2003 issue of the US magazine FLYING. The article by author Les Abend was called Beyond the Rubble; The crash of AA Flight 587. That crash of an Airbus A300-600 occurred at New York in November 2001.
The aircraft had taken off behind a JAL Boeing 747 and a few minutes later the tail of the Airbus separated from the fuselage causing the crew to lose control and crash. The NTSB determined that the copilot was the pilot handling when the tail separation occurred.
From the digital flight data recorder (DFDR) it was determined that the rudder may have moved to its full limits, back and forth in quick succession, in a very brief period of time. The writer of the article stated that Maneuvering speed, if that is the true definition, is not published in airline operating operating manuals. Operation Manual sections publish never-exceed speeds (Mmo) but not maneuvering speed.. Flight 587 never even came close to a limitation speed. So why did the tail exceed its ultimate load?
The Airbus 300-600 requires very little pedal movement to affect large movements of the rudder compared to other hydraulically powered transport-category aircraft. For example, only 1.5 inches of pedal travel will move the rudder to full deflection at an airspeed of 250 knots.. That is very close to the airspeed that Flight 587 attained while it encountered the wake turbulence of the preceding Boing 747. At that airspeed, rudder pedal movements requires only 37.5 pounds of applied force. At an airspeed of 330 knots, rudder pedal movement of merely one inch and a force of 30 pounds is all that is required for full deflection. The writer postulates that if the copilot of Flight 587 actually overcontrolled the rudder, do you think he would have done so if he knew there was a possibility that the tail could depart the aircraft?
The figures for full rudder travel quote above are for the A300-600. I wonder if the same figures could be valid for todays Boeing 737 or fly by wire types? Either way, it is doubtful if type rating engineering courses even mention rudder travel versus rudder pedal travel. It certainly was never covered on the Boeing 737 type rating course I did many years ago and probably not covered in current simulator training. Maybe it should be?