Discussion in 'Other Aspects of Aviation Security' started by THawk996, Sep 29, 2011.
From the CBS News web site:
Cockpit error sent 737 into Pacific nose dive
Ok, I'm not the sharpest hoe in the shed but I think I could tell rudder pedals from a door knob.
Oops... Hope that doesn't happen on my ANA flight in January!
That co-pilot must be a door knob.
I think the news agency (ANA) got some wires crossed. Rudder controls are only useful at low speeds, usually on the runway. The copilot must have done something much dumber. The actual report should be interesting.
Here is a second source of the video
It's in Japanese and I don't understand a word, so for all I know it could just be a simulation of someone playing a game.
While I don't understand Japanese I certainly could understand the graphics and all I can say is holy & throw a little :vomit:in there for good measure.
I think they said "the 737 is not certified for aerobatics".
Tell me that's not true! I want to see them in an air show.
Sadly, even my fertile imagination cannot stretch so far as seeing the red arrows aerobatic team performing in 737's
But if I hear of such an event, you will be the first to know.
Tex Johnson might have been up for it but he got smacked down in "training".
If you click on the photo of the cockpit at the link below, one can see that the door lock and the rudder control are not that far apart:
I believe the knob on the left marked rudder is the rudder trim control.
Hmm, you might be right on that, I guess that the word RUDDER is a clue.
When I first looked at the control I thought it might be rudder control for the autopilot but looking at the other nearby controls I believe it is Rudder Trim which is entirely different than direct rudder control.
Don't know what you know about aircraft but trim tabs are used to take force off of the controls so the pilot feels a more balanced weight on the yoke. It would take a lot of trim tab movement to make the aircraft behave as reported so I think something is missing in the report. In fact direct rudder input by the pilot would overcome the trim setting although the pilot would experience a very heavy control feel.
I am unfamiliar with a cockpit layout, but above the knob labeled "RUDDER" is a gauge that appears to be labeled "RUDDER TRIM" (though the "RU" is cropped out of the photo). Presumably turning the knob would produce some change in the gauge.
Based on the proximity of the two knobs, I can see how an inattentive or distracted co-pilot could turn the wrong knob. As to whether this would cause the plane to do a near barrel roll, I have no idea.
Rudder trim is used normally to compensate for other malfunctions that cause the plane not to fly in a straight line, e.g. engine shutdown, defective flap dragging. If he just snapped it over as though it were the door lock knob, he immediately set it to a very high degree of rudder trip for an airplane in flight at 500+ MPH.
By itself that should not cause the plane to roll if the plane were otherwise perfectly trimmed and level, but think of the aerodynamic forces at 500+ MPG once your wing is out of trim (up or down) and the tail is trying to move to one side. Suppose the wing dips -- you now have the wing being pushed down & the rudder trying to pull the rear end of the plane up & over the wing.
Mike, I don't know how much stick time you have but flight control trims are used to neutralize the stick and rudder forces so the control force is reduced to near zero. You can liken it to holding pressure to keep the aircraft from moving in a certain direction, trim is introduced to balance out that force.
I agree that all airplanes are not perfectly in trim, especially at different air speeds and control configuration. Example, some aircraft after the gear is extended take a fairly large elevator trim correction to re-balance the stick, otherwise the pilot is having to use a fair amount of force to hold the nose of the aircraft at the desired pitch. Small aircraft usually only have elevator trim while larger aircraft will have trim tabs on all three flight axis controls.
On multi-engine aircraft, rudder trim is negligible under normal operating conditions. You accomplish the same thing by adjusting engine thrust without increasing drag & fuel consumption.
Aviation Herald Online now has an article on this -- definitely the sudden application of rudder trim:
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