MD-8Xs elevator

[B767PL]

Everyday I see MD-8Xs takeoff. As they are rolling onto the runway, or taxing the right elevator is always higher then the left. It seems to go down as they are positioning on the runway. What is the reason for this?? I didnt know they can move independantly of one another.

Its just something thats bugging me because I cant figure out what purpose this serves.

heres a pic :
http://www.!!!!!!!!!!!!!!/open.file/616777/M/
http://www.!!!!!!!!!!!!!!/open.file/383390/M/
http://www.!!!!!!!!!!!!!!/open.file/382601/M/

Those show what im talking about pretty well.

[woderick]

A quick search would have found This
Sorry can't be bothered typing it out again

[B767PL]

Thank you, I guess I missed that one.

[PatagoniK]

MD 80īs elevators

The elevator control system on the MD80īs is a pair of elevators attached to the horizontal stabilizer. The elevator control is, for normal flying, an aerodynamic boost system that operates a single control tab on each elevator. Each tab is driven by its corresponding control column, both of them attached by a torque tube.
This is a short resume of the MD-80 Flight Crew Operating Manual.

I hope I was clear enough.

[B767PL]

http://www.geocities.com/roger_forgues/Boost-tabs.html

So it works something like that basiclly? Is that about right?

Thank you for your reply!