[fingpilot]

Originally posted by Tom Z.
This is almost certainly a floating flight spoiler.

SNIP.....

The term 'floating' is at stake here. If it was 'floating', it would not be spoiling lift. It would be freely floating, partly extended by flow of air lifting it from perfect stowed trail, but also perfectly opposed by the flow itself. FLOATING.

Different from extended (powered extended). How do we know? The autopilot had to counteract the powered extend (and the resulting spoiled lift) by compensating with aileron.


Since the spoiler panel is raised, a loss of lift occurs, which requires a counter input to keep the wing level.

You got it right that time, but did not use the term floating.

The amount of aileron deflection appears to be a lot, but remember that it's an inboard aileron without much roll-inducing horsepower. The opposite inboard aileron wouldn't show nearly this much deflection due to the assymetrical travel of ailerons... the downward aileron always travels further than the upward aileron.

The term adverse yaw. It means rigging ailerons so that the upward deflecting alieron ALWAYS deflects more than a downward deflecting one. Always. The drag from the downward one is so onerous (and causes adverse yaw), that it is much easier spoilng lift by deflecting the opposite aileron upwards instead. No adverse yaw that way. So how do we explain this pic? Hmmmmm. Somethings' not right.


Chances are that the upward-travelling aileron still appeared faired. This plane is going to burn a lot of extra fuel in this condition, especially on a long flight!

VERY true

This is almost certainly NOT an example of a misrigged flight control because of the onerous double and triple-checking and inspecting that accompanies rigging procedures.

SNIP

Hmmmmm. Dismissing the photographic fact that there clearly is something wrong by saying it didn't happen here in maintenance is frightening.

My $.02 worth from an Boeing-qualified airline maintenance instructor, although not a 747 instructor.

Nonetheless. I would bet .38 cents that it has been fixed correctly the first time back to the home base.